How to Manage Pests

UC Pest Management Guidelines


Citrus

Selectivity of Insecticides and Miticides

(Reviewed 9/08, updated 6/13)

In this Guideline:


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 some insects than others, it is a selective insecticide. For example, some selective insecticides cause less harm to many natural enemies than to the target pest. Insecticides that are not selective, or kill a wide range of insects including natural enemies, are called broad-spectrum. Examples of broad-spectrum pesticides include most organophosphate (e.g., malathion, dimethoate), carbamate (e.g., carbaryl–Sevin, methomyl–Lannate), pyrethroid (e.g., beta-cyfluthrin–Baythroid, fenpropathrin–Danitol), and foliar-applied neonicotinoid (imidacloprid–Provado, acetamiprid–Assail) insecticides. If broad-spectrum insecticides are used in a selective manner, such as in baits, spot treatments, or applied systemically through irrigation water, some of the detrimental effects on natural enemies can be avoided.

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, citrus thrips can be controlled with the broad-spectrum organophosphate dimethoate and the carbamate insecticide formetanate hydrochloride (Carzol) or with selective insecticides such as sabadilla (Veratran), abamectin (Agri-Mek, etc.), or spinetoram (Delegate). Lepidopterous pests, such as fruittree leafroller and citrus cutworm, can be controlled with broad-spectrum organophosphate and carbamate insecticides (chlorpyrifos–Lorsban and methomyl–Lannate) or with selective Bacillus thuringiensis microbial insecticides (Javelin, Dipel, etc.) or the stomach poison cryolite (Prokil Cryolite and Kryocide). Finally, armored scale can be controlled with broad-spectrum organophosphate and carbamate insecticides (chlorpyrifos–Lorsban, methidathion–Supracide, and carbaryl–Sevin), by selective narrow range oil treatments, or by releases of Aphytis parasites. Botanical, microbial, and oil insecticides are not disruptive to most natural enemies. Oil can reduce natural enemies present at the time of treatment but is fairly selective because of its limited persistence. In addition, some broad-spectrum pesticides can be relatively selective when used infrequently and at very low rates: for example, 0.5 pint per acre of chlorpyrifos (Lorsban) for katydids, compared to high rates (6 to 12 pints per acre) used for California red scale.

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, and predatory mites, and beetles are very susceptible to this group of pesticides. Insect growth regulators such as pyriproxyfen (Esteem) and buprofezin (Applaud) are safe for parasitic wasps but are very toxic to beetles such as the vedalia beetle needed for cottony cushion scale control. The miticide dicofol (Dicofol) 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 (2 to 3 months or more with detrimental impacts on beetles). 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, chlorpyrifos (Lorsban) residues are toxic to adult Aphytis for 3 to 6 weeks, methidathion (Supracide) affects adults for 9 weeks, and carbaryl (Sevin) affects adults for 5 months after the treatment. In the case of the predatory mite Euseius tularensis, some San Joaquin Valley populations have developed resistance to chlorpyrifos (Lorsban) and their populations are unaffected by this pesticide, but they are easily killed for several months by the carbamate formetanate hydrochloride (Carzol). Occasional, single treatments of broad-spectrum pesticides are much less harmful to natural enemies than multiple selective treatments.

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 treatment. For example, the range of activity for dimethoate is listed as "Broad (insects)." This means dimethoate affects most groups of insects. It also has an impact on 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). And finally, in instances where resistance has been observed in either the pest or natural enemy, this information is included.

Factors Affecting the Selectivity of Treatment Materials for Citrus Pest Management
Treatment material Range of Activity Resistance
Pests targeted Persistence against pest Natural enemies affected Persistence against natural enemies
abamectin (Agri-Mek, etc.) intermediate (citrus thrips, mites, leafminers) intermediate predatory mites & thrips intermediate no
(Clinch) 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 long 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 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 (Brigade) trunk spray broad (insects and mites) long unknown (likely few) unknown no
buprofezin (Applaud) narrow (scales, whiteflies) intermediate predatory beetles intermediate no
carbaryl bait narrow (earwigs, grasshoppers, cutworms) intermediate none none no
carbaryl (Sevin XLR Plus) broad (manyinsects) long most natural enemies long aggravates mites; resistance in some armored scale populations; resistance in some Euseius tularensis populations
chlorantraniliprole (Altacor) narrow (aphids, psyllids, caterpillars) intermediate parasitic wasps intermediate no
chlorpyrifos (Lorsban) broad (many insects) low rates-short

high rates-intermediate

most natural enemies low rates-short

high rates-intermediate

resistance in some armored scale and citricola scale populations; resistance in some Euseius tularensis populations and Aphytis melinus populations
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 (Kryocide, 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
cyfluthrin (Tombstone) broad (many insects and mites) intermediate most long resistance in some San Joaquin Valley citrus thrips populations
Treatment material Range of Activity Resistance
Pests targeted Persistence against pest Natural enemies affected Persistence against natural enemies
dicofol (Dicofol) narrow (mites) intermediate predatory mites intermediate resistance in some citrus red mite and twospotted spider mite populations
diflubenzuron (Micromite) intermediate (katydids, peelminer, leafminer, grasshoppers) intermediate predatory beetles intermediate no
dimethoate (Dimethoate) broad (many insects) intermediate most natural enemies long resistance in some citrus thrips populations
disodium tetraborate narrow (sugar-feeding ants) as long as the bait station is filled none none no
etoxazole (Zeal) narrow (mites) intermediate predatory mites intermediate no
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
fenproximate (Fujimite) narrow (mites) intermediate predatory mites intermediate 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
(Provado)
narrow (citricola scale, aphids) intermediate mostnatural enemies intermediate no
imidacloprid, systemic (Admire, Nuprid) narrow (aphids, glassy-winged sharpshooters) long predatory beetles and parasites intermediate no
imidacloprid (Vitis Liquid Ant Bait) narrow (sugar-feeding ants) as long as the bait station is filled none none no
iron phosphate (Sluggo) narrow (snails) intermediate beneficial snails intermediate no
malathion broad (many insects) intermediate most natural enemies 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
methidathion (Supracide) broad (many insects) long most natural enemies long resistance in some armored scale and vedalia beetle populations
methomyl (Lannate) broad (many insects) short most natural enemies intermediate no
methoxyfenozide (Intrepid) narrow (caterpillars) intermediate few intermediate 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
propargite (Omite) narrow (mites) intermediate predatory mites intermediate resistance in some twospotted mite populations
pyrethrin (PyGanic) broad (insects) short most short no
pyrethrin + piperonyl butoxide (Pyrenone Crop Spray, etc.) broad (many insects) very short most natural enemies very short no
Treatment material Range of Activity Resistance
Pests targeted Persistence against pest Natural enemies affected Persistence against natural enemies
pyriproxyfen (Esteem) narrow (armored scale insects) long predatory beetles long no
(Esteem Ant Bait) narrow (fire ants) as long as the bait station isfilled none none no
pyridaben (Nexter) narrow (mites) intermediate predatory mites intermediate no, but stimulates citrus thrips
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) very short predatory thrips very short no
s–methoprene (Tango) narrow (sugar-feeding ants) as long as the bait station is filled none none no
spinetoram (Delegate) narrow (thrips, katydids) intermediate predatory thrips intermediate resistance in some citrus thrips populations
spinosad (Success, Entrust) narrow (thrips, 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, leafminer, aphids, armored scales) long predatory mites short no
sticky materials narrow (trunk climbers) long few, if any long no
thiamethoxam (Actara) – foliar broad (many insects) long most long no
thiamethoxam (Platinum) – systemic narrow (sucking insects) long predatory beetles and parasitic wasps intermediate 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 broad (many insects and mites) intermediate most natural enemies long no

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441
General Pesticide Information

  • E. E. Grafton-Cardwell, Entomology, UC Riverside and Kearney Agricultural Center, Parlier
  • J. G. Morse, Entomology, UC Riverside
  • N. V. O'Connell, UC Cooperative Extension, Tulare County
  • P. A. Phillips (emeritus), UC IPM Program, UC Cooperative Extension, Ventura County
  • C. E. Kallsen, UC Cooperative Extension, Kern County
  • D. R. Haviland, UC Cooperative Extension, Kern County

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