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 (also called 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. 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.

Biorational Disease Control

Biorational disease control products (fungicides, bactericides, and nematicides) fall into the same classes as the insecticides, botanicals, minerals, and synthetics. Sulfur, potassium bicarbonate, phosphites and copper compounds are examples of minerals or synthetics that can control fungal and bacterial diseases. Organic growers should be sure to check with their certifying authority for more information on these materials. Botanicals such as rosemary oil, soybean oil, or garlic extracts appear in this table and are generally approved for use in organic production. These products require thorough coverage, application at the first signs of disease, and frequent repeated dosages to be effective.

Microbial products are all living organisms that require specialized storage and application procedures. These include beneficial fungi and bacteria (Streptomyces, Gliocladium, Trichoderma harizanum) 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 phylloplane (leaf surface) is especially problematic, as the competing organisms must establish themselves and can fail due to dessication and exposure to sunlight. These materials have a limited shelf life, must be protected from temperature extremes, and correctly applied (plenty of water and under the correct environmental conditions) to be effective.

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.
bifenzate 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.

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 integrated pest management strategy, which relies on monitoring for early detection of pests and emphasizes the use of selective products that provide control while preserving the ecological health of the farm and 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 insecticide products 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 (http://www.omri.org/omri-lists). 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. 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 in producing the product may be prohibited.

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.

Beneficial Insects

Biological control is taking place in fruit crops whenever the existing populations of natural enemies are conserved. The impact of natural enemies is often underestimated but may become obvious if they are killed by broad-spectrum insecticides. However, they are not always sufficient to bring pests under economic control. The release of mass-reared beneficials can also aid in suppressing pests. This tends to be more successful in greenhouses than in the field, but there are now several instances where releases in the field have been proven to suppress, if not completely control, key pests.

For example, beneficial nematodes are very small roundworms 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.