Pest Management

Information About Pesticides

A pesticide can be referred to by : 1) a common name (active ingredient) or 2) a trade or brand name.  In most of the tables in this guide, trade names are used as they are more easily recognized and are what you will look for when buying pesticide materials.

Labeled Formulations: The recommendations within this publication list only one formulation. Growers should be aware of other formulations. The rates to be applied are on the label. Note: There may be several products registered with the same active ingredient. Each label is different, and some crops may be listed on some labels but not on others. It is the responsibility of the user to read the label and be sure that the material selected is labeled for the proposed use.  Ask your supplier for clarification if you are not sure if the formulation or product is exactly what you are looking for.

Labels are for your protection and information: Look for the percentage (by weight) or amount of material in the formulation. Compare costs of two similar products on the basis of effectiveness, the amount of actual pesticide contained and the quantity of the formulations needed/acre.  Follow all safety precautions. Some pesticides are extremely dangerous to handle. Protect yourself and your employees.

Control of pests not on the label: Always be certain the crop is on the label before using a pesticide on that crop. Pests that are not listed on the label may not be effectively controlled by that product.

To avoid illegal residues: Adhere strictly to pre-harvest interval (PHI). Accurately calibrate your equipment; never exceed label recommendations. Prevent drift to adjacent properties or crops, or contamination of bodies of water. The applicator is held responsible for problems caused by drift or contamination. High-volume, low-pressure, ground applications cause less drift than low-volume, high-pressure, air-blast, ground applications, aerial applications or dust.

Emulsifiable concentrates (EC) are less troublesome to spray equipment than wettable powders (WP). The water-based flowable concentrates and wettable powders are less likely to cause plant injury than oil-based concentrates of similar materials.

Wettable powders/suspendable powders (WP) are less likely than ECs to cause injury to sensitive plants or to cause trouble when mixed with fungicides or other pesticides.

Dry flowables (DF) are similar to wettable powders in their formulation but are pelletized to minimize dust.

Flowables (F) are liquid formulations with similar properties to latex paint. Clean equipment immediately after use.

Tank mixture and aerial application: Check the label and consult your state pesticide regulatory agency.

Disposal of pesticides: Read label. Contact your state pesticide regulatory agency for instructions on disposal of chemicals.

Restricted-Use Pesticides

In accordance with federal and state pesticide regulations, those pesticides that are highly toxic and those that persist and accumulate in the environment are placed on a restricted-use list and shall be sold and used only by certified applicators.  For information about training for certified applicators contact your Extension Specialist.  In some instances, states may require additional permits for certain pesticide users.

Poisoning Information

Make sure your doctor has a copy of the Note to Physicians that is placed on the labels of dangerous pesticides. Treatment for pesticide poisoning is very precise. The antidotes can vary for the different pesticides. In an emergency, call your doctor and provide specific information on the trade name and common name of the pesticide exposed to. Your doctor will then consult the center if necessary.

Pesticide Storage

Any restricted pesticide or container contaminated by restricted pesticides must be stored in a secure, locked enclosure while unattended. That enclosure must bear a “pesticide storage” warning sign readable at a distance of 20’. If any pesticide has to be stored in other than its original container, that container must be labeled with the name and concentration of the active ingredient and the signal word and warning statements for the pesticide along with a copy of the label. Keep an inventory of all pesticides stored in an area away from the storage site, so that it may be referred to in case of an emergency at the storage site.

Make available to personnel at all times: a respirator with chemical cartridge, gas mask with canister, goggles, rubber gloves and aprons, fire extinguisher and a detoxicant for spilled materials suggested by your local fire department. Instruct all personnel on proper use of the above equipment and on what to do in case of emergency. A shower stall with plenty of soap should be made available on the premises. Prompt washing in case of accidental spillage may be a matter of life and death.

Keep your local fire department informed of the location of all pesticide storage areas. Fighting a fire that includes smoke from burning pesticides can be extremely hazardous. Firefighters should be cautioned to avoid breathing any smoke from such a fire. A fire with smoke from burning pesticides may endanger people in the immediate area or community. They may have to be evacuated if the smoke from a pesticide fire drifts in their direction.

Storage Guidelines

  • Store pesticides in a cool (between 40° and 80°F), dry, well-ventilated area that is not accessible to children and others who do not know or understand the safe and proper use of pesticides.
  • Pesticides should always be stored in their original containers and kept tightly closed. For the protection of others, especially firefighters, the storage area should be posted as Pesticide Storage and kept securely locked.
  • Herbicides, especially hormone-like weed killers such as 2,4-D, should not be stored with other pesticides (primarily insecticides and fungicides) as they can volatize and be absorbed by other pesticides.
  • Plan pesticide purchases so that supplies are used by the end of the growing season. When pesticides are stored for the winter, keep them at temperatures above freezing, under dry conditions and out of direct sunlight. 
  • If pesticides have frozen, place pesticides in warm storage (50° to 80°F, or 10° to 26.7°C). Shake or roll container every few hours to mix product or eliminate layering. If layering persists or if all crystals do not completely dissolve, do not use product. If in doubt, call the manufacturer.
  • Read the label. Special storage recommendations or restrictions will be printed on the label.
  • Write the purchase or delivery date of the product on the label with waterproof ink. Products may lose their effectiveness over several years.
  • Monitor pesticides for signs of quality deterioration (See Table 7)
Table 7. Signs of pesticide deterioration
FORMULATION GENERAL SIGNS OF DETERIORATION
EC Evidence of separation of components such as sludge or sediment. Milky appearance does not occur when water is added.
Oils Milky appearance does not occur when water is added.
WP, SP Excessive lumping; powder does not suspend in water.
D, G Excessive lumping or caking

Diagnosing Plant Problems

Effective fruit crop production depends on the grower developing a system of crop management that is appropriate for each farm. Decisions need to be made for how to manage all of the normal cultural practices such as planting, fertility, harvesting, and pruning as well as managing the insect, disease, and weed problems that occur either regularly or sporadically. The information in this guide will address management issues related to both common, expected pest problems as well as the occasional appearance of minor pest problems.

Effective pest management depends on:

  • correct diagnosis of the problem and correct identification of the pest causing it.
  • use of techniques to prevent or delay infestations or infections as well as techniques to control them.
  • early detection of pests by frequent inspection of plants.
  • tolerance of pests at population densities that do not cause economic damage.

Diagnostics

Correct diagnosis of a problem and correct identification of the pest (insect, disease, biotic factor, nutrition, etc.) causing it are key to successful crop management and profitability. Below is a list of laboratories that offer disease diagnostics on a fee-for-service basis.  In general, virus screening is a procedure that is done outside of this region and is referred out by one of the clinics listed below. Contact your local clinic or lab for more information on virus screening.

In order to submit a sample for diagnosis, some basic preparation instructions should be followed. These include:

  1. Collect specimens that show a range of symptoms (i.e., from healthy to seriously affected), usually collected from the margin of the affected area. Avoid specimens that are completely dead or decayed as they are not diagnostically useful.
  2. Fill out case-history or sample submission form like the one at the end of this guide. This is very important. Without the information included in the form, a correct diagnosis is very difficult.
  3. Pack specimen in dry paper and place in a plastic bag (never pack with wet paper towels).
  4. Mail specimen and case-history form same-day or overnight delivery, or deliver specimen personally the same day. If this is not possible, place in a refrigerator and mail or deliver the following day. Specimens should come to the diagnostic labs early in the week to avoid problems with weekend hold-overs.
  5. Soil samples for nematode analysis.

Plant Diagnostic Clinics of New England

(D=disease ID, I=insect ID, N=nematode analysis, W=weed ID)

CONNECTICUT

The Plant Disease Information Office (D,I,W,N)
The Connecticut Agricultural Experiment Station
123 Huntington Street, P.O. Box 1106
New Haven, CT 06504
https://portal.ct.gov/CAES/PDIO/PDIO-Home/PDIO-Home
(203) 974-8601

UConn’s Home & Garden Education Center (D,I,N)
Radcliffe Hicks Bldg, Rm 4
1380 Storrs Rd., Unit 4115
Storrs, CT 06269

MAINE

Insect Pest and Disease Diagnostic Lab (D,I)
Pest Management Office
17 Godfrey Drive
Orono, ME 04473-3692
https://extension.umaine.edu/ipm/ipddl/
1-800-287-0279 (within Maine)
(207) 581-3880

MASSACHUSETTS

UMass Extension Plant Diagnostic Laboratory (D,I,N,W)
Room 3, French Hall
230 Stockbridge Road
Amherst, MA 01002
https://ag.umass.edu/services/plant-diagnostics-laboratory
(413) 545-3208

NEW HAMPSHIRE

UNH Plant Diagnostic Lab (D,I,W)
Barton Hall, 34 Sage Way

RHODE ISLAND

URI Plant Protection Clinic (D,I)
3 East Alumni Avenue
Kingston, RI 02881
http://web.uri.edu/ceoc/plantclinic/
(401) 874-2900

VERMONT

University of Vermont Plant Diagnostic Clinic (D,I,W)
Attn: Ann Hazelrigg
201 Jeffords Hall, 63 Carrigan Drive
University of Vermont
Burlington, VT 05405
https://www.uvm.edu/extension/pdc
(802) 656-0493

VIRUS TESTING

Agdia Inc. (D)
30380 County Rd. 6
Elkhart, IN 46514
www.agdia.com
(800) 622-4342

Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is the coordinated use of pest and environmental information to design and implement pest control methods that are economically, environmentally and socially sound. IPM promotes prevention over remediation and advocates integration of multiple control strategies to achieve long-term pest management solutions.

IPM consists of gathering information, interpreting data, creating a flexible management plan, making timely decisions and taking the proper action. Information gathering and decision-making techniques include: accurate pest identification, learning about the weak link in a pest's life cycle or biology, scouting and monitoring crops in fields, using action thresholds to minimize spraying, and keeping records of findings to assess the effectiveness of management decisions.

Monitoring Pests and Making Control Decisions

  • Accurate pest identification is a crucial first step on the road to a solution. Misidentification of pests is a common cause of pest control failure and crop damage. See the "Diagnostics" section for more information on identification.
  • The biology and life-cycle of a pest often reveals the key to successful control measures. Detailed, pest-specific information is available in fact sheets on IPM web sites or publications listed in the Appendices. See also specific crop listings in this guide for basic descriptions.
  • Scouting involves using systematic methods of inspecting the crops on a regular basis to quantify pest populations or crop injury/damage. Scouting techniques vary considerably depending upon the type of pests (weed, insect, disease or other) involved. Details are available in pest and crop-specific IPM fact sheets and manuals, and in crop listings in this guide.
  • Monitoring weather conditions or Trapping pests can be used to assess or predict current or future pest problems and help to prevent crop damage. Equipment and procedures vary by pest and more resources can be found in the Appendices.
  • Action thresholds are usually expressed as a fixed number for individual pests (i.e., 7 moths/week or 2 weeds/foot of row) or crop injury (i.e., 20% defoliation), or as a rating for weather conditions (i.e., 15 Disease Severity Units). Thresholds tell you when to control the pest(s) to prevent or minimize economic damage to crops. Some thresholds are given for pests in the individual crop sections in this manual and others vary by state or region. Contact your state's Extension IPM personnel for local action thresholds.
  • Record-keeping involves recording data on weather, pest populations, crop conditions and control procedures all season. Good records help determine which pest control strategies are working and where improvements should be made in the future.

Along with information gathering and decision-making techniques, a variety of preventative and curative control methods are used to construct a complete IPM management plan for each pest, crop and farm. Cultural, mechanical, physical, genetic, and biological controls help prevent severe pest problems, while pesticides are used when additional control measures are required.

  • Cultural controls are modifications of the crop production systems that suppress pest populations and occurrence. A few examples include: the use of better site selection, crop rotation, modifying planting times or plant spacing, improved water and nutrient management for better crop health or to limit weed competition, breaking up plow pans, cleaning soil from machinery between fields, and the use of cover and smother crops.
  • Mechanical and physical controls consist of using supplies, equipment, or some factor, such as temperature, humidity or light, to disrupt pest life cycles and/or suppress populations. Mechanical and physical controls function by cutting, crushing, burying or excluding pests with implements and barriers, or by heating, cooling, drying, wetting, or regulating light in some way. Some examples include: plowing, cultivation, flaming, plastic or organic mulches, row covers, greenhouse ventilation, washing, cold storage and roguing infected plants.
  • Genetic controls are generally achieved through traditional breeding programs that select crop varieties with resistance or tolerance to insects, nematodes or diseases or with plant growth characteristics which favor plant success (such as early emergence, heat or cold tolerance, canopy or leaf traits).
  • Biological control is the use of naturally occurring or introduced beneficial organisms to control or suppress pest populations. Biological control agents come in all shapes and forms including: beneficial insects, mites, spiders, nematodes, fungi, bacteria, viruses, protozoa and plants. In the broadest interpretation, they would include things like microbial pesticides and the use of trap crops. Common examples range from parasitic wasps, entomophagus and competitive fungi and bacteria, to predacious bugs, beetles and spiders. Natural enemies of pests exist everywhere in nature and should be preserved whenever possible. Many beneficials can be purchased for use in the greenhouse or for specific crops.
  • Pesticides should be used in conjunction with the control measures previously mentioned and only when pest population densities will cause economic damage, or when environmental conditions favor disease. Selective insecticides are products that primarily target the pest(s) you wish to control, with few or no detrimental effects on most beneficials. They may also have other attributes making them less harmful to the user and the environment and may be lumped into a larger category of Biorational pesticides (see Biorational Pesticide section). If the use of a pesticide is required, choose a selective product or another biorational pesticide if possible. Selective insecticides usually spare biological control agents, reduce the risk of secondary pest outbreaks, reduce the impact on the environment, improve farm safety, and minimize the number of applications needed. Broad-spectrum insecticides usually kill many different kinds of pests and beneficial organisms. The use of broad-spectrum insecticides can often lead to resurgence of primary pest populations due to a lack of natural controls, or to secondary pest outbreaks and additional applications. Broad-spectrum insecticides should only be used if no other viable options exist to manage the pest. Proper pesticide application and resistance management techniques should be used to maximize the effectiveness and preserve the useful life of the available products.

Much of the space in this publication is dedicated to lists of pesticide options for weeds, insects and diseases on specific commodities. Effective pest management involves much more than using pesticides. For detailed information on IPM, see the list of publications in the Appendices section, or visit your local Extension System's IPM web site.

Pesticide Safety and Use

Who can apply pesticides

Farmers who use pesticides may require pesticide applicator licenses or permits according to state and federal law. It is important to check with your state lead agency (SLA) for pesticide regulation to determine what is appropriate in your state.  In general:

  • Farmers who apply restricted use pesticides on their crops need to have a private applicator license or permit.
  • Workers who help someone who is licensed or certified to apply restricted-use materials may also need a license to assist. 
  • Farmers who use only general use pesticides may also require licenses or permits; these requirements vary from state to state.
  • In most states, commercial (for hire) applicators must follow rules that are more restrictive than those of private applicators. 

Please note that the requirements of the EPA Worker Protection Standards (WPS) must still be followed regardless of whether a pesticide license or certification is required.  See the section below on WPS.  As of this printing, the following are contacts who can provide information on specific requirements for pesticide licenses and certification for each state.

Connecticut: 860-424-3369, http://www.ct.gov/deep/cwp/view.asp?A=2710&Q=324260
Maine: 207-287-2731, https://www.maine.gov/dacf/php/pesticides/applicators/licensing.html
Massachusetts: 617-626-1784, http://www.mass.gov/eea/agencies/agr/pesticides/
New Hampshire: 603-271-3550, http://agriculture.nh.gov/divisions/pesticide-control/index.htm
Rhode Island:  401-222-4700, http://www.dem.ri.gov/programs/agriculture/pesticides-regulatory.php
Vermont:  802-828-2431, https://agriculture.vermont.gov/public-health-agricultural-resource-management-division/pesticide-programs

 

All pesticides are poisonous. However, some are more toxic than others. The toxicity of the pesticide is usually stated in the precaution label. For example, a skull and crossbones figure and the signal word “Danger” are always found on the label of highly toxic (Toxicity Class I) materials. Those of medium toxicity (Toxicity Class II) carry the signal word “Warning.” The least toxic materials (Toxicity Class III) have the signal word “Caution.” The toxicity of a pesticide is expressed in terms of oral and dermal LD50. LD50 is the dosage of poison that kills 50% of test animals (usually rats or rabbits) with a single application of the pure pesticide for a given weight of the animal (mg/kg of body weight). The lower the LD50 value, the more toxic the material. Oral LD50 is the measure of the toxicity of pure pesticide when administered internally to test animals. Dermal LD50 is the measure of the toxicity of pure pesticide applied to the skin of test animals. Generally, an oral application is more toxic than a dermal one.

Table 8. Toxicity Categories and Signal Words
TOXICITY
CATEGORY
SIGNAL WORDSA
REQUIRED ON LABEL
ORAL LD50
(MG/KG)
PROBABLE LETHAL ADULT
HUMAN DOSE
I Highly Toxic DANGER and POISON,
plus skull and crossbones symbol
0 to 50 A few drops to 1 tsp
II Moderately Toxic Warning 50 to 500 1 tsp to 2 tsp
III Slightly Toxic Caution 500 to 5,000 1 oz to 1 pint (1 lb)
IV Almost non-toxic Caution more than 5,000 1 pint (1 lb)
Note: certain products may use signal words which do not correlate with LD50 ratings due to some special property of the chemical. For example, chlorothalonil has a very low toxicity (LD50 10,000 mg/kg) yet has DANGER signal words on many of its formulations, due to eye toxicity/injury.

All pesticides listed in this publication are registered and cleared for suggested uses according to federal and state regulations in effect on the date of this publication. Follow current label.

Trade names are used for identification only; no product endorsement is implied, nor is discrimination intended against similar materials.

Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of reach of children, pets and livestock. Dispose of empty containers carefully and properly. Contact your State Lead Agency (SLA) for pesticide regulation located in either the state Department of Agriculture or state Department of Environmental Protection for current disposal regulations and guidelines.

Before Using Pesticides

Read and post safety rules and the list of poison control centers. See instructions on safe storage of pesticides in an earlier section of this chapter. You should become familiar with the information on storage and toxicity of pesticides listed in the appendix of this guide. Similar pesticide products may not have the same crop uses. Always be certain the crop is listed on the product label before ordering or using the product.

Do not use concentrations greater than stated on the label. Do not apply more pesticide per acre or more frequently than the fewest number of days between applications recommended by the label.

Instruct your family, co-workers and farm laborers on the safe use of pesticides, protective clothing and reentry regulations concerning pesticides. See section on worker protection standards.

Do not spray or dust when bees are active in the field. Morning or late evening is usually the best time to spray.

Precautions

  • Read and follow all directions and safety precautions on labels.
  • Store pesticides in original containers, out of reach of children, pets and livestock.
  • Dispose of empty containers immediately in a safe manner and place. Triple rinse.
  • Do not contaminate forage, watersheds or water sources.
  • Become familiar with life cycles of pests to properly time applications.
  • Keep a complete diary of applications: crop, date of planting, pests, weather conditions, materials, date of application and amounts applied.
  • Adhere to farm worker protection standards.

Emergency Information

Human Exposure

If someone has swallowed or inhaled a pesticide or gotten it in the eye or on the skin:

  • Call 911 if the person in unconscious, having trouble breathing, or having convulsions.
  • Check the label for directions on how to give first aid.
  • Call the Poison Control Center at 1-800-222-1222 for help with first aid information.

The National Pesticide Information Center (NPIC) (1-800-858-7378) can also provide information about pesticide products and their toxicity.

Spills

The National Response Center (NRC) is the sole federal point of contact for reporting oil and chemical spills. If you have a spill to report, contact NRC at 1-800-424-8802 (toll-free) or visit their website (https://www.epa.gov/emergency-response/national-response-center) for additional information on reporting requirements and procedures. The NRC can help you decide how to respond to a spill. Producers should be aware that they may be required to report spills to their state Lead Agency (SLA) for pesticide regulation or their state department of environmental protection.

The Comprehensive Environmental Response, Compensations, and Liability Act (CERCLA) requires that all releases of hazardous substances exceeding reportable quantities be reported by the responsible party to the National Response Center (NRC). Title 40 of the Code of Federal Regulations Part 302 promulgates reportable quantities and reporting criteria. All the Extremely Hazardous Chemicals (EHS) that overlap with the CERCLA listed chemicals table (40 CFR Part 302.4) should be reported to NRC as well as to the LEPC and SERC.

For small pesticide spills or for more information, call the pesticide manufacturer or the National Pesticide Information Center (NPIC) at 1-800-858-7378.

More Information

CHEMTREC maintains a large database of Material Safety Data Sheets, chemical information references, resources, and networks of chemical and hazardous material experts who can provide access to technical information regarding chemical products (Emergency call 1-800-424-9300, in the U.S. or 703-741-5500 outside the U.S.).

For more information, contact the National Pesticide Information Center (NPIC) at 1-800-858-7378.

Fumigation: Materials and Risks

The practice of soil fumigation carries significant risks. These risks include the health and safety of agricultural workers and others who can be exposed to these materials, environmental risks from misapplication or accidents and other hazards.  Another risk is treatment failure from reintroducing pathogens on transplant material or farm equipment. This can cause a phenomenon called “the boomerang effect” in which a pathogen is (re)introduced in a partially sterilized soil and proliferates rapidly because checks and balances no longer exist in that soil. In such a case, the resulting epidemic is worse than if the soil had never been fumigated. So, it is very important to take care to plant very clean transplant material and to use only clean equipment when working in a newly fumigated field.

Fumigation is also a costly practice, one which a grower must carefully consider before using. The cost must be justified by the anticipated benefits. The benefits must be reliable and predictable. Moreover, availability of fumigants may decline in the future due to EPA restrictions and voluntary withdrawal by manufacturers. With this in mind, it is advisable to implement effective crop rotation plans and other soil management practices in anticipation of reduced availability of fumigants.

New Regulations Concerning Fumigation

Fumigants are very biologically active and produce gases that can readily move off site, so they can also be very dangerous to people and other organisms in the surrounding environment. Labels for most soil fumigants were extensively revised in 2011 to require additional steps of fumigant applicators (called risk mitigation measures) to safeguard the general public, the applicators and handlers, and the environment. These requirements are discussed on current fumigant labels. Reading and understanding the new soil fumigant labels is critically important. Additional revisions to these new soil fumigant labels are being developed, further increasing the importance for growers to study the labels and visit EPA’s website. Key changes already in effect include the following:

  • All chemical fumigants are now “restricted use.” Previously, metam sodium, metam potassium, and dazomet were considered general use materials.
  • Soil fumigant applicators must write a fumigant management plan (FMP) that outlines how the application will be made and describes plans to address problems should any arise. Custom applicators must provide growers with a copy of the FMP, which must be maintained for a period of two years.
  • Practices previously recommended to improve efficacy and reduce off-gassing are now requirements, such as proper calibration, soil tillage before application, fumigating when soil temperature and moisture levels are within the proper ranges, etc.
  • Maximum application rates are being reduced in some instances and untarped applications for some materials can no longer be made.
  • Respiratory protection requirements for those involved with fumigant application or tarp perforation or removal have been significantly expanded and include medical evaluation and fit-testing for respirator use.
  • The 48-hour “reentry interval” following soil fumigant application has been changed into a 5-day “entry restricted period.”
  • Unless trained/licensed by their state for fumigation (fumigant category), people must now take EPA Fumigant Training.  See https://www.epa.gov/soil-fumigants/soil-fumigant-training-certified-applicators.

Additional new label requirements include the establishment and posting of restricted-entry buffer zones around application sites, among other changes.  Updates and templates of required forms are available on EPA’s website at https://www.epa.gov/soil-fumigants

Site Preparation For Chemical Fumigation and Treatment Guidelines

Fumigation must be done carefully in order to be effective. Soil fumigation treatments should be planned well in advance so that the site can be prepared properly. Several rules apply to most treatments.

  1. Prepare the soil by deep plowing followed by disking. The purpose is to loosen the soil throughout what will be the crop rooting zone and to thoroughly incorporate all plant residues. Do this at least 3 weeks in advance of fumigation so that buried plant residues begin decomposing. Remove all woody or bulky accumulations of plant residues and large rocks from the site. These will foul the chisel applicators, decrease the effectiveness of the job, increase the hazard to workers who must clear them, and can cause a custom applicator to legally withdraw from a contract job.
  2. If the soil is dry one week prior to treatment, thoroughly wet down the soil to at least 6 inches deep by sprinkler irrigation. Do not attempt to fumigate soil that is too wet or too dry. At the 6- to 8-inch level, a handful of soil should not clump tightly when squeezed, but it should have enough moisture to feel cool in the hand and remain in a loose clump when it is released. Soil that feels warm to the touch or that is crumbly and dusty is too dry. Some moisture in the soil encourages weed seed germination and is necessary for the fumigant to kill nematodes and fungi. Soil that is saturated will limit movement of fumigants through soil so that some of the soil to be treated may not be exposed to the product.
  3. Soil temperatures at the time of treatment should be above 40°F at the 5- to 6-inch depth to allow for adequate volatilization of the fumigant but below 80°F to avoid too rapid an escape of the chemical. Optimal soil temperatures vary among different fumigants. Consult the label for the fumigant you are using for its specific temperature requirements.
  4. Chisel fumigants in at least 10 to 12 inches deep with the shanks set 8 to 12 inches apart for broadcast treatments over the whole planting site. Because strip or row fumigation only treats a portion of the field, less chemical is used per field acre, and it is useful for annual strawberry production systems. However, this practice is not recommended for perennial systems where treated areas could be recolonized over time.
  5. Soil should be sealed as stated on the product label. Leave treated sites undisturbed for at least 5 to 7 days.
  6. Aerate treated sites to allow any residual fumigant and ammonia (a temporary side effect of fumigation) to escape before planting. Aeration times vary with the type of material used, soil type, temperature, and moisture level. Check the label for details. At least 14 to 21 days should pass between the application of most soil fumigants and the time a crop is planted. Details are available on the manufacturer’s label. A simple lettuce quick test can be done to determine whether planting in fumigated soil is safe. Collect a soil sample from the treated field (do not go below the treated depth). Place the sample in a glass jar with a screw-on lid. Firmly press numerous seeds of a small-seeded vegetable crop (lettuce, radish, etc.) on top of the soil (moisten if necessary) and tighten the lid securely. Repeat the process in another jar with nonfumigated soil to serve as a check. Observe the jars within 1 to 2 days. If the seeds have germinated, planting in the field is safe. If the seeds have not germinated in the fumigated sample and have germinated in the nontreated sample, then the field is not safe to plant. Wait and retest.
  7. Fumigation kills most weed seeds, but it can also stimulate the germination of some species, such as Carolina geranium, velvetleaf, and morning glory. Use of chloropicrin has been shown to stimulate yellow and purple nutsedge emergence. Treat these problem weeds with herbicides before they become established.
  8. For annual plasticulture strawberries, fumigation must be completed at least 21 days before planting. The optimal planting date varies widely within the region and also depends on plant type used. Thus, fumigation may need to be completed as early as early summer in cooler areas of New England when using dormant plants or as late as early fall for warmer areas of Virginia when using plug plants. The best timing for fumigation is early fall if planting matted-row strawberries, brambles, or blueberries in the spring, as soil conditions that satisfy the specific temperature and moisture requirements of fumigants are more likely to exist in the fall. The usually wet and often prolonged cool spring conditions in the region often cause delays in fumigation attempts in the spring. If fumigation is done in the fall prior to spring planting, a winter cover crop of small grains or a permanent between-row sod cover can be seeded after aeration.
  9. Make sure to plant disease-free crops and use good management practices to avoid reintroducing pathogens.

 

Table 9. Fumigants and spectrums of activity
Common Name Trade Name Allowable application Methods Rate as Stated on Label* (see also next column) Conditions  Under  Which  Listed  Rate  Applies For Control Of:
          Nematodes Fungi Weeds
Metam-Sodium Vapam HL Shank, chisel, etc.; drip irrigation; solid-set irrigation, others listed 37.5-75 gal per treated acre All listed application methods yes yes yes
Comments: Water-soluble liquid that decomposes to a gaseous fumigant. Efficacy affected by soil moisture, temperature, texture, and organic matter content. May be less effective on nematodes than 1,3-D and possibly iodomethane.  VAPAM HL is phytotoxic. Protect valuable, non-target plants by stopping soil applications of this product at least three feet short of the drip line of trees, shrubs and other desirable plants.
Metam-Potassium K-Pam HL Shank, chisel, etc.; drip irrigation; solid-set irrigation, others listed 30-62 gal per treated acre All listed application methods yes yes yes
Comments: Water-soluble liquid that decomposes to a gaseous fumigant. Efficacy affected by soil moisture, temperature, texture, and organic matter content. May be less effective on nematodes than 1,3-D and possibly iodomethane.  K-PAM HL is phytotoxic. Protect valuable, non-target plants by stopping soil applications of this product at least three feet short of the drip line of trees, shrubs and other desirable plants.
1,3Dichloropropene Telone II Shank, chisel, etc. May not be applied through any type of irrigation system 27-35 gal per acre (label states product may be concentrated in the row) Annual or Perennial plantings on mineral soils yes no no
Comments: Liquid that diffuses as a gas through soil. Effective against nematodes and insects. Rates vary with soil texture; efficacy strongly affected by soil moisture and temperature.  May have some suppressive effect on Symphylans and Wireworms.
1,3Dichloropropene Telone EC May be applied only through a drip system 9-24 gal per acre broadcast equivalent Annual or Perennial plantings on mineral soils yes no no
Comments: Liquid that diffuses as a gas through soil. Effective against nematodes and insects. May have some suppressive effect on Symphylans and Wireworms.  Rates vary with soil texture; efficacy strongly affected by soil moisture and temperature. If the material is applied only to beds and not row middles, rates must be reduced proportionately. This can be calculated as follows: product rate x bed width/ row spacing. Not labelled in all New England states.

Biological Controls

Biological control is taking place in fruit crops all the time, because native and naturalized populations of natural enemies overwinter on the farm and move into crops to feed on or lay their eggs into pest insects. Predators consume several insects over the course of their development. Parasites and parasitoids tend to lay eggs in their host insect, which then feed internally, develop and kill the host. Pathogens invade the body of the host insect. The impact of beneficial insects is often underestimated because it is easy to overlook and difficult to measure. It may become obvious if they are killed by broad-spectrum insecticides and pest outbreaks occur as a result. Conservation of beneficials by use of selective insecticides when pests exceed threshold levels is recommended wherever practical.

The release of lab-reared beneficials can also aid in suppressing pests. These tend to be more successful in greenhouses than in the field, but there are several instances where releases in the field have been proven to suppress or completely control key pests. For example, Neoseiulus fallacis and Phytoseiulus persimilis are tiny mite predators that feed on pest mites such as two-spotted spider mites and European red mites. N. fallacis is indigenous to the Northeast as well as available for release from reared populations in commercial insectaries. Both have been very useful tools for New England fruit growers.

Another example involves beneficial nematodes, very small roundworms that attack soil-dwelling insects. Two in particular (Steinernema and Heterorhabditis) have been mass-reared for commercial use. These seek out and penetrate their host insects, multiply within the host and kill it. They are most likely to be effective against the soil-dwelling immature stages of susceptible hosts, such as root weevils, cutworms, white grubs, wireworms, and maggots. Nematodes require moist soil conditions to survive. Consult the Resources section in the appendices of this guide for sources of further information and suppliers of beneficial organisms.

Biorational Pesticides

Pesticides vary in their toxicity and in their potential ecological impact. Pest control materials that are relatively non-toxic to people with few environmental side effects are sometimes called “biorational” pesticides. These fit well into an IPM strategy, which relies on monitoring for early detection of pests and emphasizes the use of selective products that provide control while minimizing negative effects on beneficial insects that suppress pests. The term ‘biorational’ is a qualitative term intended to help provide information and guidance for decision making. All pesticides have some toxicity; always read and follow the label regarding agricultural use requirements and personal protective equipment. All of the pesticides listed as biorationals in the tables below carry the signal word “Caution”, the least toxic classification, on the label. None are federally restricted-use products. Most have dermal and oral LD50 values over 2,000 mg/kg.

Some, but not all, biorationals are approved for use on crops that are certified organic under the National Organic Program. For a given active ingredient, some products or formulations may be approved for use in certified organic crops, while others are not. Products that are generally approved for organic production are designated "OMRI" or "OMRI listed," which indicates they are listed on the website of the Organic Materials Review Institute (https://www.omri.org/about-products-list). Growers should consult with their certifying agency to be sure which products are approved for use.

Table 10 lists biorational insecticides and biological controls for insect management. Table 11 lists biorational fungicides and biological controls for disease management. The major categories of biorationals include botanicals, microbials, minerals, and synthetics.

Botanicals are plant-derived materials and include pyrethrin, azadiractin and neem oil, garlic, capsaicin, and vegetable oil. Botanicals are generally short-lived in the environment, as they are broken down rapidly in the presence of light and air. In general, these products require thorough coverage, application at the first signs of disease, and frequent repeated dosages to be effective. Products derived from the seeds of the Neem tree, including azadiractin and neem oil, are selective and have low mammalian toxicity. Garlic and capsaicin act primarily as repellents and thus need to be reapplied as long as pests are present. They are registered for use on a wide range of crops and pests. However, none are listed in this Guide for commercial use unless they carry the proper agricultural use requirements on the label. Vegetable oil may be derived from soybean, corn or other plants; the only labeled product for commercial use is produced from soybean oil. 

Microbial pesticides are formulated microorganisms or their by-products. They tend to be selective, so specific pests may be controlled with little or no effect on non-target organisms. Microbial insecticides include bacteria (Bacillus thuringiensis and spinosad) and fungi (Beauvaria bassiana). While these active ingredients are generally approved for organic crops because of their natural origin, certain formulated products are prohibited because the inert ingredients or procedures used to make the product may be prohibited. Microbial pesticides are often living organisms that require specialized storage and application procedures. These include beneficial fungi and bacteria (Streptomyces, Gliocladium, Trichoderma harzianum) that compete with plant pathogenic fungi, produce toxic metabolites, or actively parasitize pathogens. Their effectiveness in University research trials has been inconsistent because of variations in environmental conditions and disease pressure. Microbial fungicides perform best in a greenhouse environment where they can establish and flourish. Control of plant pathogenic organisms on the leaf surface is especially problematic, as the competing organisms may have difficulty becoming established due to dessication and exposure to sunlight. These materials have a limited shelf life, must be protected from temperature extremes, and must be applied correctly (with plenty of water and under the correct environmental conditions) to be effective.

Minerals and synthetics. Some biorational pesticides are minerals, mined from the earth and minimally processed. Kaolin clay, insecticidal soap, and iron phosphate are examples. Minerals that are heated, chemically reacted, or mixed with surfactants may be considered synthetics. Synthetics include growth inhibitors or insect growth regulators (IGR), materials that interrupt or inhibit the life cycle of a pest.

Table 10. Biorational Insect and Mite Control Materials.
Active Ingredient Trade Name(s) Target Pests Comments
azadiractin Aza-Direct, Azatin XL,
Neemix
Aphids, leafminers, thrips, whitefly, leafhopper, flies, true bugs, some beetles and caterpillars Insect growth regulator, repellent, antifeedant. Disrupts growth of immature stages. Use preventatively before outbreaks. Repeat applications may be needed. Efficacy varies.
Beauvaria bassiana
strain GHA
Mycotrol O,
BotaniGard 22WP
Aphids, whiteflies, thrips This fungus penetrates the insect cuticle, proliferates and eventually releases new spores. Best applied in evening. Use preventatively based on monitoring before pest populations are high.
Bacillus thuringiensis
subsp. kurstaki

Biobit,
Deliver,
Dipel,
Javelin
Caterpillars, including cranberry/cherry fruitworm, blueberry sawfly, winter moth, grape berry moth, leafrollers, etc. Acts as stomach poison, must be ingested to be effective. Not all products are OMRI listed; check the label.
Bacillus thuringiensis
subsp. aizawai
Agree WG Caterpillars, including armyworms, grapeleaf skeletonizer Acts as stomach poison, must be ingested to be effective. OMRI listed.
bifenazate Acramite 50WS,
Floramite SC
Mites A long residual selective nerve poison for mite control.

Burkholderia spp.
strain A396
Venerate Caterpillars, scale insects Highly active against grape berry moth.  Make two applications 7-days apart for each generation when needed.
Grandevo and Venerate can be rotated but do not tank-mix the two products together.

Chromobacterium subtsugae
strain PRAA4-1
Grandevo Grape berry moth, mites, spotted wing drosophila suppression Early application is important for Grandevo against any of the sucking pests as the primary MOA is reduction in reproduction and typically a 7-day application interval or shorter is needed. 
Highly active against grape berry moth.  Make 2 applications 7 days apart for each generation when needed.
Grandevo WDG at 3 lb/acre + adjuvant for spotted wing drosophila.
extract of neem oil Trilogy Primarily labeled for (but not limited to) mite control Can be used to control mites. For best results use when population levels are low to prevent build-up. Repeat applications are needed. Do use on table grapes after bloom or on wine grapes after bunch closure.
potassium salts of fatty acids (insecticidal soaps) M-Pede, Des-X Aphids, leafminers, mites, thrips, whiteflies Works on contact. Can be phytotoxic to some crops, test on small plot first. Avoid treatment when plants are stressed or air temperatures are above 85˚F. May also harm some beneficials. Also active against powdery mildew. Do not use on table grapes onces they become 6-7 mm or use at lowest recommended rate (75 gal/A)
iron phosphate Sluggo Snails, slugs Bait which causes feeding to cease. Death occurs over 3-5 days. Exempt from tolerance and has a zero hour reentry interval due to low mamalian toxicity.
methoxyfenozide Intrepid Many species of caterpillar Insect Growth Regulator. Mimics molting hormone; causes premature molt and death. Labeled for Grape Berry Moth.
pyrethrin Pyganic EC,
Pyrenone Crop Spray
Many pests of fruit crops; see label. Botanical insecticide with broad-spectrum activity. Contact toxin with rapid knockdown bur short residual. Highly toxic to fish. Derived from chrysanthemum. Some formulations OMRI listed.
spinosad Entrust 2SC Caterpillars, leafminers, thrips Acts both as a contact and stomach poison. Somewhat toxic to some beneficials. Rotate with other selective biorationals to prevent the development of resistance.
spiromesifen Oberon Whiteflies and some mites Contact insecticide and miticide.
Steinernema and Heterohabditis
parasitic nematode species
Beneficial Nematodes White grubs, weevil larvae, wireworms Predatory nematodes seek out and penetrate host insects, multiply within the host and kill it. They are most likely to be effective against soil-dwelling immature stages of susceptible host insects. They require moist soil conditions to survive.
Table 11. Biorational Disease Control Materials
Active Ingredient Trade Name(s) Target Pests Comments
Acibenzolar-S-methyl Actigard 50 WG Downy mildew, Xanthomonas Plant defense activator.
Bacillus amyloliquefaciens Triathlon, Double Nickel Botrytis, Alternaria, fungal leaf spots and blights, Powdery mildew Most recommendations are to mix Double Nickel with Cueva.
Bacillus pumilus strain QST 2808 Sonata Powdery mildew, rust, leaf spots  
Bacillus subtilis QST Serenade Max Botrytis, leaf spot, Anthracnose, Powdery mildew  
Calcium polysulfide Lime-Sulfur (various manufacturers) Cane and spur blights, Phomopsis, Fusicocum, overwintering inoculum of Monolinia This is a caustic compound that must be thoroughly cleaned from spray equipment to avoid damage. Some formulations are OMRI listed.
Copper hydroxide Champion WP, Champ, Nu-Cop, Kocide Botrytis, Downy mildew, Powdery mildew, Anthracnose, Phomopsis Be careful of potential phytotoxicity in some crops or cultivars; do not apply in close succession with Captan; read label carefully for cautions and restrictions.
Copper octanoate Cueva Powdery mildew, leaf spots, Anthracnose, Botrytis
Copper sulfate Cuprofix-Ultra 40 Disperss Powdery mildew, leaf spots, Anthracnose  
Harpin protein Messenger Bacterial diseases, adverse environmental conditions Plant defense activator; variable efficacy
Hydrogen dioxide Oxidate Alternaria, Phytophthora, Pythium, Rhizoctonia, Anthracnose, Botrytis, Powdery mildew Kills on contact by oxidation. Will also kill beneficial organisms. Requires repeated applications.
Kaolin clay Surround WP Powdery mildew, heat stress, sunscald Creates a thin film of clay particles on the surface of treated plants. Must be rinsed off of harvested fruit if residue persists.
Laminaria digitata plant extract Vacciplant Botrytis, Anthracnose, mummyberry Plant defense activator. Start applications preventatively or when conditions for disease development become favorable. Reapply every 7 – 14 days. Under moderate to heavy disease pressure, tank mix this product with another registered fungicide.
Neem oil Trilogy
Agroneem
Azatrol
Aza-Direct
Neemix
Anthracnose, Botrytis, Downy and Powdery mildew Also effective for insect and mite control. Repeat applications needed for good control.
Potassium bicarbonate Kaligreen
Armicarb
MilStop
Alternaria, Botrytis, Downy and Powdery mildew  
Potassium phosphite ProPhyt, Phostrol Downy mildew, Phytophthora Systemic material
Mono- and dibasic sodium, potassium, and ammonium phosphites Phostrol Downy mildew, Pythium, Phytophthora Systemic material, see label for tank mix cautions
Pseudomonas fluorescens BlightBan A506 Strawberry frost protection and grape bunch rot protection
For strawberry frost protection, start application when first bloom initials emerging from crown. Repeat treatments as necessary, with a total of 2-3 applications.
As an aid to control bunch rot caused by species of Acetobacter bacteria (sour rot) in combination with Aspergillus niger and Botrytis cinerea. Apply at bloom and again prior to bunch closure.
 
Reynoutria sachaliensis (giant knotweed) Extract Regalia Botrytis, Anthracnose, mummyberry Plant extract to boost plants’ defense mechanisms to protect against certain fungal and bacterial diseases, and to improve plant health.
Applications need to start early.
Regalia + NuFilm P for control of mummyberry and anthracnose fruit rot.
 
Streptomyces lydicus Actinovate AG Powdery mildew, Botrytis  
Sulfur

Kumulus

Microthiol
 

Powdery mildew Be careful of potential phytotoxicity in some crops or cultivars; do not apply in close succession with Captan; read label carefully for cautions and restrictions.

Protecting Honeybees & Native Pollinators

Honeybees and native pollinators visit fruit crops during flowering and pollen shed. In crops such as blueberries, their activity is crucial to the success of the crop. In other crops such as grapes, bees are among many beneficial insects who seek out pollen or nectar resources as a food source, but crop yield does not depend upon their activity.  Strawberries and brambles benefit from the presence of pollinators but are also achieve some level of pollination from wind blown pollen.  Populations of honeybees and native pollinators have declined worldwide in recent years. A wide range of factors have contributed to their decline; pesticides applied to crops is one of these.

Pesticides applied to protect fruit crops can affect pollinators through multiple routes of exposure: direct contact with sprays, contact with treated surfaces, pesticide-contaminated dust or pollen particles that are collected or adhere to the body of the insect (and may be taken back to hive), and ingestion of pesticide-contaminated nectar. Decisions made by the farmer make a difference in the exposure of bees and other beneficials to lethal or sublethal levels of pesticides. While pesticides applied to crops are only one among many factors that threaten pollinators, this is one factor that growers can do something about. Taking precautions to minimize pesticide poisoning of pollinators in all crops is an important responsibility of all pesticide applicators.

Reducing pesticide injury to honey bees requires communication and cooperation between beekeepers, farmers and applicators. It is important that beekeepers understand cropping practices and pest management practices used by farmers in the vicinity of their apiaries. Likewise, insecticide applicators should be sensitive to locations of apiaries, obtain a basic understanding of honey bee behavior, and learn which materials and application practices are the most hazardous to bees. While it is unlikely that all poisonings can be avoided, a balance must be struck between the effective use of insecticides, the preservation of pollinators and the rights of all--the beekeeper, farmer and applicator. In most cases, bee poisonings can be avoided by observing the following practices.

Steps that can reduce pesticide exposure of pollinators

Timing.  Avoid applications when crop or weeds are in bloom. In crops that bloom over long periods, make applications late in the day or at night when pollinators are not foraging, and so that there is sufficient drying time before foraging begins.  Control weeds within the planting but allow for some blooming native plants in field edges and hedgerows as forage habitat when crops are not in bloom.  Take care to avoid spray drift in areas where pollinators are foraging when spraying.

Formulation. Wettable powders, dusts and microencapsulated products have a greater toxic hazard than emulsifiable concentrates (or other liquid formulation with active ingredient in solution). Products that do not have acute toxicity but could cause injury to immature bees if carried back to the hive should not be applied in particulate form; this includes insect growth regulators.

Drying time before exposure. Some products are highly toxic when wet, but much less so after the pesticide is dried. Spinosyns have this characteristic. Apply when there will be adequate drying time (usually 2-3 hours, depending on weather conditions and crop canopy) before pollinator activity. Applying these materials in the evening can help achieve good drying before pollinators become active again the following day. If temperatures following treatment are unusually low, insecticide residues can remain toxic longer than if higher temperatures prevail.

Drift. Avoid drift on non-target areas near the field where blooming plants may be located. Windspeed and application equipment both influence drift. In general, sprays should not be applied if wind speed exceeds 10 mph.

Mode of application. Soil applications reduce exposure compared to foliar applications, unless plant uptake of the active ingredient produces residues in pollen or nectar. In the case of neonicotinoids, there is evidence that foraging bees may receive sublethal doses in pollen and nectar when crops were treated with a systemic at early growth stages. This effect appears to be reduced by using lower rates and applying as early as possible, but may not be entirely eliminated by these methods. A sublethal dose may make bees more vulnerable to other stressors, or may combine with doses from contact with other treated plant material.

Acute toxicity. EPA registration includes an acute, single-dose laboratory study designed to determine the quantity of pesticide that will cause 50% mortality (LD50) in a test population of bees.

Read the label for bee hazard rating. If a pesticide is used outdoors as a foliar application, and is toxic to pollinating insects, a “Bee Hazard” warning and easily identified Bee icon is required on the label. In addition a standardized information box is also required. 

The EPA bee toxicity groupings and label statements are as follows:

High (H) Bee acute toxicity rating: LD50 = 2 micrograms/bee or less. The label has the following statement: "This product is highly toxic to bees and other pollinating insects exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees or other pollinating insects are visiting the treatment area."  If the residues phrase is not present, this indicates that the pesticide does not show extended residual toxicity.
Moderate (M) Product contains any active ingredient(s) with acute LD50 of greater than 2 micrograms/bee,  but less than 11 micrograms/bee. Statement: "This product is moderately toxic to bees and other pollinating insects exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product if bees or other pollinating insects are visiting the treatment area."
Low (L) All others. No bee or pollinating insect caution required.

For an easy to use, sortable list of materials, their EPA bee toxicity ratings and synergistic effects with other materials see: https://www2.ipm.ucanr.edu/beeprecaution/ 

See below, Tables 12a and 12b, for information about the hazards posed to non-target organisms by several common small fruit pesticides. 

Table 12A. Poisoning hazard to honey bees of common small fruit pesticides.
Active Ingredient
(common product names)**
DURATION OF HAZARD TO HONEYBEES (Residual Toxicity) Active Ingredient
(common product names)**
DURATION OF HAZARD TO HONEYBEES (Residual Toxicity)
EXTREMELY to Highly TOXIC: DO NOT APPLY ON BLOOMING CROPS OR WEEDS
*Beta-cyfluthrin
(*Baythroid, *Leverage, *Tempo)

1 day RT§
> 1 day ERT§§
 

Lambda-cyhalothrin
(Warrior, Voliam)
> day ERT
> day ERT for encapsulated formulation
*Bifenthrin
(*Brigade, *Sniper)
< 1 day RT
> 1 day ERT
Malathion
(Malathion, Cythion)
2-6 hrs RT
2-5 days ERT
Carbaryl
(Sevin)
< 1 day RT
2-14 day ERT
*Methomyl
(*Lannate, *Nudrin)
2 hrs RT
1.5 days ERT
*Chlorpyrifos
(*Dursban, *Lorsban)
2 hrs RT
4-6 days ERT
*Naled
(*Dibrom)
2 hrs RT
1-1.5 days ERT
Clothianidin
(Belay, Clutch)
? RT
> 5 days ERT
Phosmet
(Imidan)
3-5 days ERT
Copper Sulfate + Lime
(Bordeaux Mixture)
? Pyrethrin
(Azera, Pyganic, Pyrenone)
< 2 hrs RT
*Cyfluthrin
(*Baythroid, *Tombstone, *Tempo)
? RT
> 1 day ERT
Pyridaben
(Nexter, Pyramite, Sanmite)
< 2 hours RT
> 8 hrs ERT
*Diazinon
(*Diazinon)
? RT
2 days ERT
Sabadilla
(Veratran-D)
1 day ERT
Dinotefuran
(Venom, Scorpion)
? RT
39 hrs ERT
Sulfoxaflor
(Closer)
3 hrs RT
*Esfenvalerate
(*Asana)
< 1 day RT
1 day ERT
Thiamethoxam
(Actara, Platinum, Voliam)
7-14 days ERT
*Fenpropathrin
(*Danitol)
< 1 day RT
1 day ERT
*Zeta-cypermethrin
(*Mustang, *Hero, *Mustang Max)
> 1 day ERT
Imidacloprid
(Admire, Brigadier, Merit, Pasada, Provado)
8 hrs RT
> 1 day ERT

 

 

Indoxacarb
(Avaunt)

     
MODERATELY TOXICA: APPLY ONLY DURING LATE EVENING, NIGHT, OR EARLY MORNING IF BLOOMING PLANTS ARE PRESENT.
Acetamiprid
(Assail)
2 day ERT Copper Hydroxide
(Badge, Champ, Kocide, Nu-Cop)
?
Azadirachtin
(Neemix, Aza-Direct, Azera)
2 hr RT Horticultural Oil
(Superior, Dormant, Summer)
< 3 hr RT
Beauvaria bassiana
(Mycotrol, Botaniguard)
? Novaluron
(Rimon)
?
Bifenzate
(Acramite)
? Oxydemetonmethyl
(Metasystox-R)
< 2 hours RT
Capsacin
(Hot pepper wax)
? Petroleum/Paraffinic Oil
(JMS Stylet Oil)
< 3 hours RT
Chlorfenapyr
(Phantom, Pylon)
< 4 hr RT
> 2 day ERT
Spinetoram
(Delegate, Radiant)
3 hour RT
Spinosad
(Entrust, Success)
?
Chromobacterium subtsugae
(Grandevo)
? Spirotetramat
(Movento)
?
SLIGHTLY TOXIC OR NONTOXIC: CAN BE APPLIED AT ANY TIME WITH REASONABLE SAFETY TO BEES.
Acequinocyl
(Kanemite)
  Lime Sulfur
(Lime Sulfur)
 
Aluminum tris O-ethyl phosphonate
(Alliette, Fosetyl-Al)
  Mancozeb
(Dithane, Gavel, Manzate, Penncozeb, Ridomil Gold MZ)
 
Azoxystrobin
(Abound, Quadris)
  Mefenoxam
(Maxim, Ridomil)

 

Bacillus subtilis
(Rhapsody, Serenade, Cease)
Laboratory tests suggest potential effects on bumble bees. Metaldehyde bait
(Deadline)
 
Bacillus thuringiensis
(BT, Agree, Javelin, Thurcide)
  Metconazole
(Quash)
 
Boscalid
(Endura, Pristine)
  Methoxyfenozide
(Intrepid)
 
Calcium Polysulfide
(Lime Sulfur, Sulforix)
  Metrafenone
(Vivando)
 
Captan
(Captan, Captec, Captevate)
Up to 7  day ERT for mason bees. Effects on honey bee brood in laboratory, but not in field tests. Myclobutanil
(Rally, Sonoma)
No impact on bumble bees.
Chlorantraniliprole
(Altacore, Coragen, Grubex)
No impact on bumble bees. Neem oil
(Trilogy)
Must be ingested to be toxic.
Chlorothalonil
(Bravo, Echo)

Tentatively associated with “entombed pollen”. Common contaminant of beeswax.

Oils: Cottonseed, Clove, Garlic
(Pest Out, GC-mite)
 
Clofentezine
(Apollo)
  *Paraquat
(*Paraquat)
Although no PS on label, laboratory studies suggest effects on honey bee larvae, and paraquat has been associated with colony losses.
Cyflufenamid
(Miltrex, Torino)
  Penthiopyrad
(Fontelis)
 
Cymoxanil
(Tanos)
  Phosphorous acid, mono and di-potassium salts
(Fosphite, Prophyt)

 

Cyprodinil
(Switch, Vanguard)
No impact on bumble bees. Polyoxin D zinc salts
(Oso, Ph-D, Tavano)
 
Dicofol
(Dicofol)
Mixing with insecticides increases hazard to bees. Potassium bicarbonate
(MilStop, Greencure, Kaligreen)
No impact on bumble bees.
Difenoconazole
(Inspire, Quadrus, Revus)
 
Progargite
(Omite)

Mixing with insecticides increases hazard to bees

Dodine
(Syllit)
  Propiconazole
(Propicure, Quilt, Tilt)
Mason bees more sensitive than honey bees. If mixed with lambda- cyhalothrin, may increase toxicity.
Etoxazole
(Zeal)
3 days ERT for bumble bees Pyraclostrobin
(Cabrio, Pristine)
 
Famoxadone
(Tanos)
  Pyrimethanil
(Luna, Scala)
 
Fenarimol
(Rubigan, Vintage)
 

Pyriproxyfen
(Esteem)

≺2 hours RT for alfalfa leafcutting and alkali bees. May be toxic to bumble bee larvae. Avoid direct application or spray drift to honey bee hives (per label).

No PS on label, other sources suggest ERT to bees.

Fenbuconazole
(Indar)
  Quinoxyfen
(Quintec)
 
Fenbutatin-oxide
(Vendex)
 

Reynoutria sachaliensis
(Regalia)

 
Fenhexamid
(Elevate)
  Spiromesifen
(Oberon)
Structure and mechanism of action similar to spirodiclofen and spirotetramat, which are potentially toxic to honey bee larvae.
Fenpyroximate
(Fujimite, Akari)
  Streptomyces lydicus
(Actinovate)
 
Flonicamid
(Beleaf)

Possible effects on honey bees, further research needed. Short RT for alfalfa leafcutting bees and alkali bees. Short RT for bumble bees.

Sulfur
(various products OMRI classification varies by product)

See also lime sulfur. While most sources say sulfur poses little risk for bees, other sources suggest sulfur may cause toxicity for bees for up to a day and a half.

Flubendiamide
(Belt, Tourismo, Vetica)
Possible effects on honey bee larval development, further research needed. Tebuconazole
(Adament, Luna, Orius)
2 days ERT for bumble bees.
Fludioxonil
(Switch)
No impact on bumble bees. Tebufenozide
(Confirm)
 
Fluopicolide
(Presidio)
 

Tetraconazole
(Mettle)

1 day ERT for bumble bees
Fluopyram
(Luna)
  Thiacloprid
(Calypso)
Less toxic to bees than most other neonicotinoids. 1-2 days ERT for bumble bees.
Hexythiazox
(Onager, Savey)
≻2 hours RT for alfalfa leafcutting and alkali bees Thiophanate-methyl
(Topsin-M)
 
Iprodione
(Rovral)
Laboratory studies suggest effects on honey bee larval development, field studies needed. Triflumizole
(Procure)
May increase toxicity of certain neonicotinoids.
Kaolin Clay
(Surround)
  Ziram
(Ziram)
Laboratory studies suggest effects on honey bee larval development, field studies needed.
Kresoxim methyl
(Sovran)
     

Sources: 2010 New England Apple Pest Management Guide and Oregon State University Bulleting PNW591 ‘How to Reduce Bee Poisoning from Pesticides’.
§ Residual Toxicity - The length of time the residues of the product remain toxic to bees after application.
§§ Extended Residual Toxicity - Residues D are expected to cause at least 25 percent EC mortality for longer than 8 hours after F application.
a Late evening means after 6-8 PM and assumes that evening temperatures are not unusually high and that bees have stopped foraging. Late evening, night or early mornings means after 6-8 PM, and before 4-7 AM, depending on temperature. Shift time if abnormally high temperatures cause bees to start foraging earlier or continue later than ususal (5:30 AM to 8:00 PM). Few honeybees forage when springtime temperature is below 51˚F. Maximum foraging activity occurs at temperatures above 63˚F. Evening applications are generally less hazardous to bees than early morning applications.
**Where trade names are used, no discrimination is intended and no endorsement by Cooperative Extension is implied. Not a complete list.
*Restricted use pesticide; pesticide applicators license required. OMRI certified for organic production

Table 12B. Toxicity of pesticides to birds, fish, bees, and beneficials.
(SOURCE: 2010 THE MID-ATLANTIC BERRY GUIDE FOR COMMERCIAL GROWERS)
  TOXICITY TO:
    MITE PREDATORS APHID PREDATORS
PESTICIDE BIRDS FISH BEES N. FALLACIS Z. MALI
INSECTICIDES
Actara Na N H N N H
Admire M M H M S S-M
Asana N H H H M H
Aza-Direct -- H N -- -- S
Brigade/Capture M H H H M H
Confirm S H M N N N
Danitol H H H H M H
Diazinon H H H M S M
*Dibrom -- -- M -- -- --
Dipel (B.t.) N N N N N N
Entrust/Spintor H -- H S N N
Esteem -- -- N S N N
Imidan S H H S S S
Lannate H H H H M H
*Lorsban M H H M M H
Malathion M H H S -- M
M-Pede N N N S S --
Mustang Max -- H H H M H
Platinum -- M -- -- -- --
Provado M M H S S M
Sevin XLR S N H M M M
*Thionex H H S S N M
MITICIDES
Acramite -- -- H M M S
AgriMek N N H H M --
Kanemite -- Hb -- S S S
Kelthane/Dicofolc M H N H S S
Oberon -- H -- -- -- --
Savey -- H N S S N
Vendex M M N M M H
Zeal -- -- N M S M

a N = reasonably safe (for bees, apply anytime); S = slightly toxic (for bees, apply in evening after bees have stopped foraging until early morning before they start foraging); M = moderately toxic (for bees, apply in evening after bees have stopped foraging); H = highly toxic (for bees, do not apply to blooming plants); — = insufficient data
b Toxic to invertebrate aquatic organisms such as oysters.
c Kelthane use is being discontinued. Growers may continue to use existing stocks for strawberries. VA’s 24C label for Kelthane on brambles is no longer in effect.

*Restricted use pesticide; pesticide applicators license required. OMRI certified for organic production

Weed Management General Notice

The primary goal of weed management is to optimize yield by minimizing weed competition. Weeds can reduce yields by competing with the crop for space, water, light, and nutrients. Weeds also promote pest injury by acting as alternate hosts for plant pathogens and insects, inhibiting spray penetration, and maintaining a high humidity in the crop canopy. Timely cultivation, wise use of herbicides and mulches, and not allowing weeds to go to seed are integral parts of a good weed management system. Many of the weeds found in small fruit plantings are difficult-to-control perennials that are not common in other crops. Do not expect chemicals to completely control weeds. Every herbicide does not control every weed species and the selection of a given herbicide should be made on the basis of specific weed species present in the field.

Herbicide rates listed on the product label are for broadcast applications. Reduce rates proportionally for banded or strip applications. For best results with herbicides, follow the manufacturer’s application directions regarding rates, additives, soil type, soil moisture conditions, time of year, crop age, stage of weed growth, environmental conditions, and product limitations.

It is unlawful to use any pesticide for other than the registered use. ALWAYS READ AND FOLLOW ALL LABEL DIRECTIONS. The user assumes all responsibilities for use inconsistent with the label on the product container.

Trade names are used for identification. No product endorsement is implied, nor is discrimination intended against similar materials not mentioned. Cooperative Extension and the participating universities make no warranty or guarantee of any kind, expressed or implied, concerning the use of these products.

Certain herbicides listed in this publication may be discontinued by the manufacturer and thus no longer available. Use of remaining stocks on dealers' shelves or farm storage is encouraged and legal provided the label directions are followed.

Herbicides - General

Herbicides are chemicals designed to control weeds. Proper rate selection, timing of application, activation, and observance of all precautions on the label must be followed to obtain optimum performance. Each herbicide controls certain weeds or families of weeds. Therefore, knowledge of the type of weed species present in the field is essential for good weed control (see the “Weeds of the Northeast” reference in the Resource Materials section). Once the weed problem is known, select the proper herbicide.

When selecting herbicides, take into account the following:

  • Restrictions on rates, timing and crops for which the herbicide is approved.
  • Degree of susceptibility of each weed to a specific herbicide.
  • Limitations and special requirements of the herbicide.

General principles for safe use:

  • Know the herbicide. Read the label.
  • Check the output of sprayer frequently.
  • Replace worn nozzles. It may be necessary to replace them several times a season if the sprayer is used constantly.
  • Avoid skips and overlapping.
  • Rinse spray equipment immediately after use. If possible, use one sprayer for herbicides and another for insecticides and fungicides.
  • Follow the Worker Protection Standards information printed on the label.

Herbicide Rate Selection

Always check the label to determine the proper rate to apply. For most soil-applied herbicides, knowledge of the type of soil and the percentage organic matter usually determines the rate. Generally, the more clay and/or organic matter present in the soil, the higher the herbicide rate necessary for good weed control. When applying herbicides to fresh mulch, use the lowest labeled rate. For postemergence herbicides, the type of weed as well as its size will usually determine the rate.

Incorporation of Herbicides

Some herbicides must be incorporated into the soil to be effective. Herbicides are incorporated because they are volatile and evaporate into the air if left on the soil surface or they will decompose when exposed to sunlight. Herbicides differ in their incorporation requirements; check the product label for the manufacturer’s requirements.

Weed Sprayer Systems

  • Select a sprayer and pump that can deliver a volume of 20 to 50 gallons per acre. Most herbicides are applied at rates of 20 to 40 gallons of water per acre. Pressures of 20 to 40 p.s.i. at the nozzle are recommended for most herbicides. Higher pressures result in finer droplets and increase the chance for more drift. Lower pressures sometimes cause uneven spray patterns.
  • Use 50-mesh screened filters for nozzles and suction lines.
  • Select 80˚ or 110˚ flat fan nozzles. Because of wear, brass tips used exclusively for applying wettable powders should not be used on more than 30 acres before being replaced. Use stainless steel or hardened stainless steel tips for longer wear. Stainless steel nozzle tips are more than twice the cost of brass tips but last about 20 times longer. Hardened stainless steel tips are only slightly more expensive than stainless steel tips but last three times longer. Ceramic nozzles are the most durable.
  • Calibrate sprayers frequently and check for wear, especially when wettable powders have been used.

Mechanical Weed Control

Cultivation is an important component of weed control in small fruits, particularly when the use of herbicides and/or mulches is to be minimized or eliminated. The timing of cultivation should be based on the stage of weed growth that your equipment is best suited to control, as well as to the stage of crop development that is most sensitive to weed pressure. In general, weeds are most effectively cultivated shortly after they germinate, and crops are most sensitive to weed pressure during their early stages of growth. Thus, cultivation is most critical early in the growing season. To get good weed control with cultivation requires use of the proper machinery, driven by a competent operator, in a timely fashion.

A variety of cultivation equipment is used by small fruit growers. These include rotovators, multivators, rolling cultivators, rotary hoes, sweep cultivators and discs, S-tine or Danish S-tine cultivators, basket weeders, finger weeders, spring-hoe and spyder weeders, and spring-tine weeders. For a full description of these cultivators, see references in resource materials section.

Stale Bed Technique

In many cases, choice of herbicides for use in newly planted small fruit crops is limited. Even when a herbicide is registered for use in the crop, certain weed species may be present which the herbicide cannot control. In many cases, it may be possible to use a method which utilizes Gramoxone, Roundup, Touchdown, Scythe or flaming. Except for cool early spring conditions, when weeds may be slow to germinate, this method, termed the stale bed technique, can mean the difference between good weed control and poor or no weed control. Here are the steps:

  • Prepare the soil for transplanting. If a soil-incorporated herbicide is used, it must be applied and incorporated at this time. The soil should have good moisture (irrigate with 1/4” of water if necessary).
  • Wait as long as possible so that weeds will germinate and emerge. Allow weed seedlings to grow to the third leaf stage, or at least to the first true leaf.
  • Flame the soil or make an application of Gramoxone, Scythe, Touchdown or Roundup (if registered for the crop) to the soil surface before transplanting. Transplant the crop and then apply any preemergence herbicide, which you would normally use, to the soil surface.

The main idea with this technique is that most of the weeds that have the potential to germinate, because of their placement in the upper 1” to 2” of the soil, will usually do so within two weeks after the soil is prepared. Adequate soil moisture and temperature (at least 50 ̊ F at a depth of 2”) must be present. Gramoxone, Roundup, Touchdown, Scythe or flaming will kill these weeds. By not redisturbing the soil any more than is absolutely necessary during the transplanting process, no new weed seeds will be brought close to the soil surface. This technique, because it reduces the number of viable weed seeds near the soil surface will also help the residual herbicide, if any, to perform better than it normally would. Finally, any cultivation which is performed should be kept extremely shallow (3/4” to 1” maximum) so as not to reposition any additional weed seeds. Note: Check the current herbicide recommendations by crop to determine if Gramoxone, Scythe, Touchdown or Roundup is registered for use in that crop.

Finally, Roundup or Touchdown can be used for control of perennial weeds, such as quackgrass and dock, during the summer or fall prior to planting. For best results, the soil should be tilled about 2 weeks after application. Rates vary considerably so check the label for directions. Control of perennial weeds in the spring will be poor. Contact herbicides, including Gramoxone, Scythe and flaming will have minimal long-term effect on perennial weeds.

Flame Weeding

Flame weeding is the killing of weeds with intense, directed heat produced by a propane burning device, either hand-held or tractor-mounted. Flaming can be used as an alternative to non-selective herbicides for stale seedbeds. This involves preparing the soil as if for planting, without actually planting the crop. Instead, weeds are allowed, even encouraged (with irrigation or row covers), to grow. Weeds are then killed. Because, like with contact herbicides, flaming kills weeds without soil disturbance, it is ideal for stale seedbeds. Some growers use hand-held units to flame just in the row, relying on cultivation for between-row weed control.

Prepared fields or beds may be flamed one or more times, depending on when weeds appear and when the crop is to be planted. Once broadleaf weeds reach the 1-3-leaf stage, they should be flamed to prevent them from growing too large. For the longest weed control effect, it is important that the final flaming be applied as late as possible or just prior to transplanting. Digging in the soil to check crop seeds for sprouting, or using a small piece of glass or row cover as an early warning system is one way to optimize the timing of flaming after direct seeding.

Flaming does not burn the weeds but “blanches” them. They will not collapse and die for several hours. There are exceptions. The growing points of grasses are usually below ground for some time and will not be affected by flaming. Purslane can take high temperatures without dying. These weeds require subsequent cultivation or hotter temperatures. When weeds are moist from rain or dew, more heat (a slower tractor or walking speed) will be necessary. Safety is a big issue with flaming. Consult with a gas professional if constructing your own flaming unit. Do not mount propane tanks intended for stationary use onto tractors. Flame against the breeze and avoid areas with dry residues or dry hedgerows. Liability concerns may hinder the use of flaming.

Soil Solarization

(Based on information in Univ. of California Pest Notes Publication 74145)

Soil solarization is a nonchemical method for controlling soilborne pests using high temperatures produced by capturing radiant energy from the sun.  The method involves heating the soil by covering it with a clear plastic tarp for 4 to 6 weeks during a hot period of the year when the soil will receive the most direct sunlight. When properly done, the top 6 inches of the soil will heat up to as high as 140°F, depending on the location. The plastic sheets allow the sun’s radiant energy to be trapped in the soil, heating the top 12 to 18 inches and killing a wide range of soilborne pests, such as weeds, pathogens, nematodes, and insects.

The effect of solarization is greatest at the surface of the soil and decreases at deeper soil depths. The maximum temperature of soil solarized in the field is usually 108° to 131°F at a depth of 2 inches and 90° to 99°F at 18 inches. Control of soil pests is usually best for organisms found in the upper 6 inches of earth. 

Soil solarization controls many of the annual and perennial weeds present in New England. However, some weed species seeds or plant parts are very sensitive to soil solarization, others are moderately resistant and require optimum conditions for control (good soil moisture, tight-fitting plastic, and high solar radiation). Solarization generally does not control perennial weeds as well as annual weeds because perennials often have deeply buried underground vegetative structures such as roots and rhizomes that may resprout. Rhizomes of bermudagrass and johnsongrass may be controlled by solarization if they are not deeply buried. Solarization alone is not effective for the control of the rhizomes of field bindweed. Control of purple and yellow nutsedge, as well as field bindweed arising from rhizomes and some clovers, can be inconsistent, even under favorable conditions.