Selectivity of Insecticides and Miticides

17 Aug.,2022

 

Thiamethoxam 30%SC

Some pesticides are less toxic than others to natural enemies such as green lacewings, lady beetles, parasitic wasps, beneficial mites, and predatory bugs. When an insecticide causes less harm to the natural enemies than the pests, it is a selective insecticide. Insecticides that kill a wide range of insects, including natural enemies, are called broad-spectrum. Examples of broad-spectrum pesticides include most organophosphate (malathion, dimethoate), carbamate (Sevin, Lannate), pyrethroid (Baythroid, Danitol), and neonicotinoid (Admire, Assail) insecticides. To reduce the detrimental effects on natural enemies, use broad-spectrum insecticides in a selective manner (e.g., in baits, spot treatments, at times of the year when natural enemies are not active, or applied systemically through irrigation water).

Within each of the major groups of pests in citrus, there are selective and broad-spectrum pesticides that can be used to control them. For instance, lepidopterous pests, such as fruittree leafroller and citrus cutworm, can be controlled with broad-spectrum carbamate insecticides (Lannate), with selective Bacillus thuringiensis microbial insecticides (Dipel), or the stomach poison cryolite (Prokil Cryolite). Armored scale can be controlled with broad-spectrum carbamate insecticides (Sevin), selective narrow range oils, selective insect growth regulators such as pyriproxyfen (Esteem) and buprofezin (Centaur), spirotetramat (Movento), or by releases of Aphytis parasites. Botanical, microbial, and oil insecticides are not disruptive to most natural enemies because of their limited persistence. In addition, some broad-spectrum pesticides can be relatively selective when used infrequently, with outside coverage, or at low rates. For example, a low rate of a highly broad-spectrum pyrethroid applied as outside coverage can easily kill katydids without disrupting natural enemies needed for scale control.

Some insecticides are selective or safe for one group of natural enemies but not another. For example, lacewings are naturally tolerant of pyrethroids, but parasitic wasps, predatory mites, and beetles are very susceptible to this group of pesticides. Insect growth regulators such as pyriproxyfen (Esteem) and buprofezin (Centaur) are safe for parasitic wasps but are very toxic to beetles such as the vedalia beetle needed for cottony cushion scale control. The miticide and insecticide spirotetramat (Movento) is safe for predatory and parasitic insects but is quite toxic to predatory mites.

Both selective and broad-spectrum pesticides can be quite persistent, or residues may degrade quickly. For example, both sabadilla (Veratran D) and pyriproxyfen (Esteem) are relatively selective, but sabadilla persists only for a short period of time (several days), whereas residues of pyriproxyfen are quite persistent (can harm predatory beetles for 2 to 3 months or more). If a persistent, broad-spectrum pesticide has been applied, residues on the plant may be harmful to natural enemies for weeks or months. For example, if adult Aphytis wasps are placed in a jar with leaves that were sprayed in the field with the dilute rate needed to control California red scale, carbaryl (Sevin) affects adults for 5 months after the pesticide application. In the case of the predatory mite Euseius tularensis, some San Joaquin Valley populations have developed resistance to organophosphates and their populations are largely unaffected by this group of pesticides. Occasional, single applications of broad-spectrum pesticides are much less harmful to natural enemies than multiple selective pesticides.

It is important to carefully consider the selectivity of a pesticide when making a treatment decision. This includes the effect the pesticide has on nontarget species, its persistence in the environment, and whether or not resistance to the pesticide has developed. These factors are listed in the table below and under each recommendation in the guideline.

  • Range of Activity is listed first and denotes the degree of selectivity each pesticide recommendation has, along with the group of organisms primarily affected by the application. For example, the range of activity for dimethoate is listed as "broad (insects)." This means dimethoate affects most groups of insects. It also harms beneficial mites as noted in the next column. On the other hand, Bacillus thuringiensis is listed as "narrow (caterpillars)" because it only affects caterpillars.
  • Persistence, or the length of time a pesticide remains effective or toxic, is listed next and is categorized as short (days), intermediate (up to 6 weeks), or long (months).
  • Resistance information is included in instances where it has been observed in either the pest or natural enemy.

Factors Affecting the Selectivity of Treatment Materials for Citrus Pest Management

  Range of Activity Common name (Example trade name) Pests targeted Persistence against pest Natural enemies affected Persistence against natural enemies Resistance abamectin (Agri-Mek) intermediate (citrus thrips, mites, leafminers) intermediate predatory mites & thrips intermediate no abamectin (Clinch Ant Bait) narrow (fire ants) intermediate other ants intermediate no acequinocyl (Kanemite) narrow (mites) intermediate predatory mites intermediate no acetamiprid (Assail) broad (many insects) intermediate most natural enemies intermediate no afidopyropen (Sefina Inscalis) narrow (aphids, psyllids) intermediate parasitic wasps short no Aphytis melinus narrow (armored scales) long, unless broad-spectrum pesticide used none none no azadirachtin (Neemix) narrow (whiteflies, aphids, leafminers, caterpillars) short few short no Bacillus thuringiensis (Dipel) narrow (caterpillars) short none none no beta-cyfluthrin (Baythroid) broad (many insects) intermediate most natural enemies low rates-intermediate
high rates-long resistance in some San Joaquin Valley citrus thrips populations bifenazate (Acramite) narrow (mites) intermediate predatory mites intermediate no bifenthrin, trunk spray (Brigade) broad (insects and mites) long unknown (likely few) unknown no buprofezin (Centaur WDG) narrow (scales, mealybugs, whiteflies) intermediate predatory beetles intermediate no carbaryl, bait narrow (earwigs, grasshoppers, cutworms) intermediate none none no carbaryl (Sevin XLR Plus) broad (many insects) long most natural enemies long aggravates mites; resistance in some armored scale populations; resistance in some Euseius tularensis populations chlorantraniliprole (Altacor) narrow (psyllids, caterpillars) intermediate parasitic wasps intermediate no chlorpyrifos (Lorsban 15G) broad (many insects) intermediate most natural enemies intermediate none for target pests Chromobacterium subterfugae (Grandevo) narrow (Asian citrus psyllid) short few short no copper bands narrow (brown garden snail only) long none none no copper sulfate narrow (snails) long, unless washed off few, if any none to short no cryolite (Prokil Cryolite) intermediate (foliage feeders such as worms, katydids, and Fuller rose beetle) long, unless washed off by rain few, if any none to short no Cryptolaemus montrouzieri narrow (mealybugs) intermediate, does not survive winters well none none no cyflumetofen (Nealta) narrow (mites) intermediate predatory mites short no cyfluthrin (Tombstone) broad (many insects and mites) intermediate most long resistance in some San Joaquin Valley citrus thrips populations cyantraniliprole, foliar (Exirel) narrow (aphids, leafminer, Asian citrus psyllid, sharpshooters, thrips) intermediate none none no cyantraniliprole, systemic (Verimark) narrow (citrus leafminer, Asian citrus psyllid, aphids) intermediate none none no cyantraniliprole/abamectin (Minecto Pro) intermediate (Asian citrus psyllid, bud mite, broad mite, citrus thrips, cotton aphid, twospotted spider mite, citrus leafminer and rust mite) intermediate predatory mites and thrips intermediate no diflubenzuron (Micromite) intermediate (katydids, Asian citrus psyllid, peelminer, leafminer, grasshoppers) intermediate predatory beetles intermediate no dimethoate (Dimethoate) broad (many insects) intermediate most natural enemies intermediate resistance in some citrus thrips populations fenbutatin oxide (Vendex) narrow (mites) short predatory mites short no fenpropathrin (Danitol) broad (many insects and mites) intermediate most natural enemies long resistance in some San Joaquin Valley citrus thrips populations fenpyroximate (Fujimite) narrow (mites, Asian citrus psyllid) intermediate predatory mites intermediate no flonicamid (Beleaf) narrow (aphids, Asian citrus psyllid) short predatory thrips short no flupyradifurone (Sivanto) narrow (soft scales, aphids, Asian citrus psyllid, sharpshooters) short parasitic wasps short no formetanate hydrochloride (Carzol) broad (many insects) intermediate most natural enemies long, unless washed off resistance in some citrus thrips populations hexythiazox (Onager) narrow (mites) intermediate predatory mites short to intermediate no hydrated lime narrow (leafhoppers) long interferes with searching ability of many natural enemies long no imidacloprid, foliar
(Admire Pro) narrow (citricola scale, aphids, Asian citrus psyllid, glassy-winged sharpshooters, whiteflies) intermediate most natural enemies intermediate resistance in some glassy-winged sharpshooter populations imidacloprid, systemic (Admire Pro and generics) narrow (aphids, glassy-winged sharpshooters, Asian citrus psyllid, citrus leafminer, weevils, whiteflies) long predatory beetles and parasites intermediate resistance in some glassy-winged sharpshooter populations imidacloprid/beta-cyfluthrin (Leverage) broad (many insects) intermediate most natural enemies long resistance to the beta-cyfluthrin in some citrus thrips populations iron phosphate (Sluggo) narrow (snails) short beneficial snails short no malathion broad (many insects) intermediate most natural enemies intermediate no mating disruption (Checkmate CRS) narrow (California red scale) long none none no metaflumizone (Altrevin) narrow (ants) intermediate other ants intermediate no metaldehyde (Deadline) narrow (snails) short beneficial snails short no Metaphycus helvolus narrow (soft scales) long, unless broad-spectrum pesticides used none none no methomyl (Lannate) broad (many insects) short most natural enemies intermediate no methoxyfenozide (Intrepid) narrow (caterpillars) intermediate few short no micronized sulfur broad (mites, citrus thrips) intermediate most natural enemies intermediate no naled (Dibrom) broad (many insects) short most natural enemies intermediate no neem oil (Trilogy) broad (softbodied insects) short few short no oil (dilute application) broad (unprotected stages of insects and mites) short most natural enemies short no oil (low-volume) narrow (citrus red mite) short predatory mites short no phosmet (Imidan) broad (many insects, mites) intermediate most natural enemies short no pyrethrin (PyGanic) broad (insects) short most short no pyrethrins/piperonyl butoxide (Pyrenone Crop Spray) broad (many insects) short most natural enemies short no pyridaben (Nexter) narrow (mites) intermediate predatory mites intermediate no, but stimulates citrus thrips pyriproxyfen (Esteem) narrow (armored scale insects) long predatory beetles long some California red scale populations pyriproxyfen, bait (Esteem Ant Bait) narrow (fire ants) intermediate none none no rosemary oil/peppermint oil (Ecotrol) broad (unprotected stages of insects and mites) short most short no Rumina decollata narrow (brown garden snail) long, unless snail bait used none none no sabadilla (Veratran-D) narrow (citrus thrips) short predatory thrips short no smethoprene (Tango) narrow (sugar-feeding ants) as long as the bait station is filled none none no spinetoram (Delegate) narrow (thrips, Asian citrus psyllid, katydids) intermediate predatory thrips intermediate resistance in some citrus thrips populations spinosad (Success, Entrust) narrow (thrips, Asian citrus psyllid, orangeworms, katydids) intermediate predatory thrips intermediate resistance in some citrus thrips populations spirodiclofen (Envidor) narrow (mites) intermediate predatory mites intermediate no spirotetramat (Movento) broad (mites, thrips, Asian citrus psyllid, leafminer, aphids, armored scales) long predatory mites short no sodium ferric edta (Ferroxx) narrow (snails) short predatory snails short no sticky materials narrow (trunk climbers) long few, if any long no thiamethoxam, foliar (Actara) broad (many insects) long most long no thiamethoxam, systemic (Platinum) narrow (sucking insects) long predatory beetles and parasitic wasps intermediate no thiamethoxam/abamectin (Agri-flex) broad (many insects) long most long no thiamethoxam/chlorantraniliprole (Voliam flexi) broad (many insects) long most long no vedalia beetle narrow (cottony cushion scale) long none none no wettable sulfur narrow (mites and citrus thrips) intermediate most natural enemies intermediate no zeta-cypermethrin (Mustang Maxx) broad (many insects and mites) intermediate most natural enemies intermediate no