Agriculture: Walnut Pest Management Guidelines

Relative Toxicities of Pesticides Used in Walnuts to Natural Enemies and Honey Bees

Common name
(Example trade name)
Mode of Action1 Selectivity2 (affected groups) Predatory Mites3 General Predators4 Parasites4 Honey Bees5 Duration of impact to natural enemies6
abamectin (Agri-Mek) 6 moderate (mites, leafminers) H L M/H I long to predatory mites and affected insects
acequinocyl (Kanemite) 20B narrow (mites) L III
acetamiprid (Assail) 4A moderate (sucking insects, larvae) 7 II moderate
Bacillus thuringiensis ssp. kurstaki 11A narrow (caterpillars) L L L III short
bifenazate (Acramite) 20D narrow (mites) L L L II short
bifenthrin (Brigade) 3A broad (insects, mites) H H H I long
buprofezin (Centaur) 16 narrow (sucking insects, beetles) L H8 L II long
carbaryl (Sevin) 1A broad (insects, mites) L/H H H I long
chlorantraniliprole (Altacor) 28 narrow (primarily caterpillars) L L L/M III short
clofentezine (Apollo) 10A narrow (mites) L L L III short
Cydia pomonella granulovirus (Cyd-X) narrow (codling moth) none none none III none
cyfluthrin (Baythroid) 3A broad (insects, mites) H H H I moderate
dicofol (Dicofol) un narrow (pest mites and mites) H M M III long to beneficial mites
diflubenzuron (Dimilin) 15 L H9 L II
emamectin benzoate (Proclaim) 6 narrow (caterpillars) I
esfenvalerate (Asana) 3A broad (insects, mites) H M H I moderate
etoxazole (Zeal) 10B narrow (mites) 10 II short
fenbutatin oxide (Vendex) 12B narrow (pest mites) L L L III short
fenpropathrin (Danitol) 3A broad (insects, mites) H H H I
hexythiazox (Onager) 10A narrow (mites) L L L II short to moderate
imidacloprid (Admire Pro) 4A narrow (sucking insects) H I short to moderate
lambda cyhalothrin (Warrior) 3A broad (plant bugs, beetles, caterpillars) H H H I moderate
malathion 1B broad (insects, mites) H H H I moderate
metaflumizone (Altrevin bait) 22B narrow (ants) III
methoxyfenozide (Intrepid) 18 narrow (caterpillars) L L L II none
methyl parathion (Penncap-M) 1B broad (insects) M M M I
permethrin (Ambush, Pounce) 3A broad (insects, mites) L H H I long
petroleum oils broad (exposed insects, mites) L L L II short to none
phosmet (Imidan) 1B broad (insects, mites) H H H I moderate to long
propargite (Omite) 12C narrow (pest mites) M8 L L III short
pyriproxyfen (Seize) 7C narrow (scale, beetles) L H11 L II long
rosemary oil/peppermint oil (Ecotrol) broad (exposed insects, mites) L L L III
s-methoprene (Extinguish) 7A narrow (ants) III
spinetoram (Delegate) 5 narrow (caterpillars, aphids, scales) L/H M12 L/M II moderate13
spinosad (Entrust, Success) 5 narrow (caterpillars, aphids, scales) L/H M12 L/M II short to moderate
spinosad (GF-120) 5 narrow (husk fly) II
spirodiclofen (Envidor) 23 narrow (mites) II
H = high    M = moderate    L = low    — = no information    un = unknown or uncertain mode of action
1 Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance.For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee).
2 Selectivity: broad means it affects most groups of insects and mites; narrow means it affects only a few specific groups.
3 Generally, toxicities are to western predatory mite, Galendromus occidentalis. Where differences have been measured in toxicity of the pesticide-resistant strain versus the native strain, these are listed as pesticide-resistant strain or native strain.
4 Toxicities are averages of reported effects and should be used only as a general guide. Actual toxicity of a specific chemical depends on the species of predator or parasite, environmental conditions, and application rate.
5 Ratings are as follows: I-Do not apply or allow to drift to plants that are flowering; II-Do not apply or allow to drift to plants that are flowering, except when the application is made between sunset and midnight if allowed by the label and regulations; III-No bee precaution, except when required by the label or regulations. For more information about pesticide synergistic effects, see Bee Precaution Pesticide Ratings.
6 Duration: short means hours to days; moderate means days to 2 weeks; and long means many weeks or months.
7 May cause an increase in spider mite numbers.
8 Use lowest rates for best management of western predatory mite/spider mite ratio (propargite).
9 High toxicity to juvenile stages of predators and reduces fertility of adult green lacewings.
10 Acute toxicity low but reproductive capacity is impacted.
11 Kills lady beetles.
12 Toxic against some natural enemies (predatory thrips, syrphid fly larvae) when sprayed and shortly thereafter (8-24 hours).
13 Residual is moderate if solution is between pH of 7 to 8.

Acknowledgements: This table was compiled based on research data and experience of University of California scientists who work on a variety of crops and contribute to the Pest Management Guideline database, and from Flint, M. L. and S. H. Dreistadt. 1998. Natural Enemies Handbook: An Illustrated Guide to Biological Pest Control, ANR Publication 3386.

Text Updated: 07/17
Treatment Table Updated: 07/17