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Characteristics of turf insecticides

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Some turf insecticides act very quickly while others take much longer to kill the target insect. In addition, some materials persist for several weeks and remain active, while others break down in a matter of a few days. Of the insecticides listed in these guidelines, a few work quite quickly (within one to three days) and break down within one to two weeks. These materials, often used for ‘curative’ applications, include: acephate (Orthene), and trichlorfon (Dylox). Some of the synthetic pyrethroids, like cyfluthrin (Tempo) and bifenthrin (Talstar) begin to act quickly but will persist longer if they penetrate the thatch and/or are applied to the soil.

Very few of the turf insecticides currently available for use in Massachusetts are intermediate in their “speed of efficacy” and persistence. These materials will often take three to seven days to begin to affect the target insects, but normally will remain active for three to five weeks, and sometimes even longer. Several “intermediate” materials have been taken off the market in the last few years, one that remains is carbaryl (Sevin).

Some insecticides, such as imidacloprid (Merit) or chlorantraniliprole (Acelepryn), are used for preventive insect control in areas that have a history of damage.  This use pattern is common for white grub management, but care must be taken to ensure that the material is in place and fully active when the grubs are in the most susceptible stage. These materials vary in how quickly they become active, but then normally remain active for several weeks or even months.
Please note that some listed materials have been somewhat inconsistent in their performance while others have provided similar levels of control through the years. Be sure to obtain current label information before using any insecticide.

Using insecticides preventively in an IPM program

Insecticides usually have either preventive or curative action against the pest for which they are used. Preventive materials are applied before a noticeable pest population develops. Curative materials are typically applied after populations reach a damaging level.

There are many components to an IPM program, including monitoring for pest activity, establishing tolerance levels, and considering cultural and biological management strategies whenever possible. One of the key tenets of IPM is to apply pesticides when a pest population exceeds a threshold level and only when all other avenues of control have been exhausted. In certain instances, however, preventive pesticide applications may be preferred to the alternative of waiting until a problem develops.  Part of the process in selecting and applying pesticides in an IPM program is to use application methods and materials that minimize the potential for environmental disruption.

For example, several turf insecticides [including the neonicotinoids and chlorantraniliprole (Acelepryn)] provide preventive protection against white grubs and are much less toxic than the older organophosphate materials that were used for many years. There are few cultural practices or effective biological control agents available that provide reliable control of white grub populations. Furthermore, in Massachusetts the use of the most effective curative material, trichlorfon (Dylox), is not allowed on school properties as specified in the Children and Families Protection Act (see the Pesticide Regulations section of this guide for more information). The only option for effective management of high populations of white grubs in this circumstance is preventive application with a neonicotinoid or chlorantraniliprole.

To be justified in an IPM plan, preventive insecticide applications must be based on scouting or other documentation of the potential for damaging populations from the previous season or seasons.

Insecticide resistance


There are several chemical classes of insecticides available to turf managers. Recently some turf insects (most notably, the annual bluegrass weevil) have developed resistance to certain chemical classes (in the case of the weevil, resistance to pyrethroids). This means that applications of certain products made now at rates that were effective several years ago do not kill as many insects. One of the most effective ways to delay the development of resistance is to avoid using insecticides in the same chemical class repeatedly. In most cases, you must also avoid using chemicals with the same mode of action. The Insecticide Resistance Action Committee (www.irac-online.org) has assigned “IRAC” numbers for each chemical class, and many chemical companies are putting these numbers on labels to make it easier for turf managers to incorporate this information into their decisions on chemical inventories. For example, any insecticide in the neonicotinoid class (e.g., Merit or Meridian or Arena) will have a black box with a white “4A” indicating the IRAC chemical subgroup. Carbamates (class 1A) and organophosphates (class 1B) are in the same group but listed separately because while the chemistry of the two classes of insecticides is different, the mode of action (cholinesterase inhibition) is the same.

The following information on insecticide characteristics will help turf managers avoid using the same chemical class repeatedly. Trade names referenced here are the first trade name under which the product was available in turf. Note that for some chemicals, there are many additional trade names not listed here.

Table 15. Characteristics of turf insecticides registered for use in Massachusetts.

ABW = annual bluegrass weevil; BTA = black turfgrass ataenius; ECF = European crane fly

Chemical class: ORGANOPHOSPHATE OR CARBAMATE IRAC class: carbamate – 1A; organophosphate – 1B
Most are “older” chemicals and, as cholinesterase inhibitors, tend to be more acutely toxic to vertebrates than some of the newer compounds. There is a lot of variation in field characteristics: Some are soluble in water while others are not; some are systemic while some are not; some are quite persistent while some are not. For example, trichlorfon (Dylox) and acephate (Orthene) are very soluble in water and can break down quickly when water pH is above 7.5. Neither is very persistent in field conditions. Most other insecticides in these classes are being phased out of the turf market.
Common name Trade name Partial list of insects on label Notes
acephate Orthene caterpillars, chinchbugs  
carbaryl Sevin caterpillars, many beetle adults, chinchbugs, ECF Very toxic to honeybees and other bees
chlorpyrifos Dursban billbug adults, caterpillars, chinchbugs, ECF Golf course only. Actively being phased out of the market and available only as generic formulations.
trichlorfon Dylox white grubs Works quickly, breaks down quickly. Susceptible to rapid breakdown with water pH above 7.0-7.2
 
Chemical class: PYRETHROID IRAC class: 3
Every pyrethroid available for use on turf is virtually insoluble in water and is bound quickly to organic matter. As a result, pyrethroids are effective against insects that are active in the thatch (e.g., annual bluegrass weevil adults, black turfgrass ataenius adults, bluegrass billbug adults, caterpillars, chinchbugs, European crane fly). ABW has developed resistance to pyrethroids in some locations, particularly between Hartford, CT and metropolitan NY. Most pyrethroids begin working three to five days after application (sometimes more quickly) and remain active for three to five weeks (sometimes longer). Labels on pyrethroids sometimes change, and there may be additional products labeled for turf that are not listed here. Most pyrethroids are toxic to fish and aquatic invertebrates, and some are also toxic to bees that are exposed to direct treatments on flowering crops and weeds. Some of the pyrethroids that are used in New England are listed below. Many pyrethroids have gone “off patent” so there are many other products available with different trade names.
Common name Trade name Partial list of insects on label Notes
bifenthrin Talstar ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF  
cyfluthrin Tempo ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF  
lambda-cyhalothrin Scimitar ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF  
deltamethrin Deltagard ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF  
 
Chemical class: NEONICOTINOID IRAC class: 4A
There are four neonicotinoids currently available in turf, and all of them are systemic through the roots.  Imidacloprid works much more slowly than most of the other insecticides available for turf. However, it appears to remain active for several weeks, and even a few months in some cases. Two of the neonicotinoids (chlothianidin and thiamethoxam) are also absorbed directly into leaf tissue to some degree. As a result they tend to work a little more quickly than imidacloprid and appear to be active on a slightly wider range of turf insects. None of the neonicotinoids are effective against Asiatic garden beetles. Neonicotinoids often take several days to start working, but remain active for several weeks or months (depending on the time of year they are applied). Even though imidacloprid has been on the turf market for more than 10 years, there have been no reports of resistance in any turf insects yet. There have been some implications that use of imidacloprid might be a contributing factor to colony collapse disorder in honeybees, but there are also many other possible explanations for that disorder. Care should be taken when using any neonicotinoid to avoid applications when honeybees are foraging, such as when clover or ground ivy is in bloom. In addition, some labels indicate products are toxic to aquatic invertebrates.
Common name Trade name Partial list of insects on label Notes
chlothianidin Arena ABW, BTA, caterpillars, billbugs, white grubs  
dinotefuran Zylam   More soluble than the others, optimum use patterns still being identified. Dinotefuran is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.
imidacloprid Merit ABW, BTA, billbugs, white grubs Merit went “off patent” in 2007
thiamethoxam Meridian ABW, BTA, caterpillars, billbugs, white grubs Thiamethoxam is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.
 
Chemical class: COMBINATION PRODUCTS IRAC class: neonicotinoid, 4A; pyrethroid, 3
Three products are now available for commercial applicators that combine a neonicotinoid and a pyrethroid. The combination provides protection against soil insects (neonicotinoid) and surface feeders (pyrethroid). Optimal timing of application depends on what the primary insect target is at a given site. (For example, if white grubs are the primary target, applications should be made just as adults become active and start laying eggs. If billbugs are the primary target, applications could be made in late May or early June to target adults as they become active.)
Trade name Contents Partial list of insects on label Notes
Allectus Merit and Talstar ABW, BTA, billbugs, caterpillars, chinchbugs, ECF, European chafer, Japanese beetle, and oriental beetle. available only to commercial applicators
Aloft Proprietary blend of chlothianidin and bifenthrin ABW, BTA, billbugs, caterpillars, chinchbugs, ECF, European chafer, Japanese beetle, and oriental beetle. available only to commercial applicators
Maxide Meridian and Scimitar ABW, BTA, billbugs, caterpillars, chinchbugs, ECF, European chafer, Japanese beetle, and oriental beetle. available for general use
Other generic combination products are also available.
 
Chemical class: OXADIAZINE IRAC class: 22
There is only one product currently available in turf that is in the oxadiazine class: indoxacarb. This class has a very low mammalian toxicity and a new mode of action. It works by blocking the movement of sodium ions into nerve cells. Product labels have the same precautionary language as pyrethroids regarding toxicity to fish and aquatic invertebrates, as well as foraging honeybees. Indoxacarb is particularly effective against caterpillars and is most effective when applications are made targeting eggs and small caterpillars.
Common name Trade name Partial list of insects on label Notes
indoxacarb Provaunt ABW larvae, caterpillars  
indoxacarb Advion turfgrass ants (bait formulation)  
 
Chemical class: ANTHRANILIC DIAMIDE IRAC class: 28
This new chemical class has a totally new mode of action and has such low mammalian toxicity, the EPA did not require the registrant to include a signal word on the label. It received federal registration in April 2008 and at least one formulation has been registered in each of the New England states. The label describes chlorantraniliprole as toxic to aquatic invertebrates, but it is relatively insoluble so it is less likely to move to surface water than some other products. It is not toxic to bees, ants, or wasps. It is extremely effective against all the white grub species we encounter in New England, but should be applied before early to mid June to achieve maximum effectiveness against grubs. Spring applications of chlorantraniliprole will not affect grubs that are present in the spring.
Common Name Trade name Partial list of insects on label Notes
chlorantraniliprole Acelepryn ABW, BTA, billbugs, caterpillars, white grubs  
 
Chemical class: SPINOSYN IRAC class: 5
This group is represented by spinosad (Conserve), which is derived from a soil actinomycete. The label describes it as highly toxic to bees and to mollusks. Effective against many caterpillars, including sod webworms, cutworms, and armyworms (as well as caterpillars in the landscape). Also a good larvacide for annual bluegrass weevil.
Common name Trade name Partial list of insects on label Notes
spinosad Conserve ABW larvae, caterpillars Apply against ABW larvae when larvae have just begun to emerge from the stem