How to Manage Pests

UC Pest Management Guidelines

Cucurbits

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

(Reviewed 12/09, updated 6/12, pesticides updated 5/16)

In this Guideline:


Cucurbits depend on bees for successful pollination. In addition, beneficial insects and mites play a key role in maintaining populations of aphids, leafminers, and spider mites below economically damaging levels. They also are instrumental in controlling populations of whiteflies, armyworms, and loopers. Some insecticides and miticides used in cucurbits are toxic to these beneficials and must be used with extreme care to minimize destruction of natural enemy populations. To ensure survival of natural enemies, use Bacillus thuringiensis (Dipel, Javelin, Biobit, etc.) or soft contact chemicals such as soaps and oils in the early plant stages, if needed, rather than harsh disruptive materials (pyrethroids, organophosphates, and carbamates). To protect honey bees, do not use moderate-to-highly toxic materials when the crop is in bloom and bees are in the field. The following table outlines the general toxicity of cucurbit pesticides to beneficial organisms.

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 SC) 6 moderate (mites, leafminers) M L M/H I moderate to predatory mites and affected insects
acetamiprid (Assail) 4A moderate (sucking insects, larvae) 7 II moderate
Bacillus thuringiensis ssp. aizawai 11A narrow (caterpillars) L L L II short
Bacillus thuringiensis ssp. kurstaki 11A narrow (caterpillars) L L L III short
bifenazate (Acramite) un narrow (spider mites) L L L II short
bifenthrin (Capture) 3A broad (insects, mites) H H H I long
buprofezin (Courier) 16 narrow (sucking insects, beetles) L H8 L II long
carbaryl (Sevin) bait 1A narrow (cutworms, army-worms, grasshoppers, etc.) L L L III short
carbaryl (Sevin 4F) 1A broad (insects, mites) M/H H H I long
carbaryl (Sevin XLR Plus) 1A broad (insects, mites) L H H I long
chlorantraniliprole (Coragen) 28 narrow (primarily caterpillars) L L L/M III short
chlorantraniliprole / lambda-cyhalothrin (Voliam Xpress) 28 / 3A broad (plant bugs, beetles, caterpillars) H H H moderate
clothianidin (Belay) 4A M/H M/H I long
cryolite (Kryocide) un narrow (foliage chewing insects) L L L III short
cyantraniliprole (Exirel,Verimark) 28 narrow (whiteflies, worms, cabbage loopers) short
cyromazine (Trigard) 17 narrow (leafminers) L L L II short
diazinon (WP, EC) 1B broad (insects, mites) L H H I moderate to long
dimethoate 1B broad (insects, mites) H H H I long
dinotefuran (Venom) 4A narrow (sucking insects) L L I short
esfenvalerate (Asana) 3A broad (insects, mites) H M H I moderate
fenpropathrin (Danitol) 3A broad (insects, mites)       I  
flubendiamide (Belt SC) 29 L L L/M II short
imidacloprid (Admire) 4A narrow (sucking insects, beet armyworm, cutworms) L III
indoxacarb (Avaunt) 22A narrow (caterpillars) L L L I moderate
insecticidal soaps broad (exposed insects, mites) M M M III short
lambda-cyhalothrin (Warrior) 3A broad (plant bugs, beetles, caterpillars) H H H I moderate
malathion (EC) 1B broad (insects, mites) M H H I moderate
methomyl (Lannate) 1A broad (insects, mites) H H H I moderate
methoxyfenozide (Intrepid) 18 narrow (caterpillars) L L L II short
oxamyl (Vydate) 1A broad (insects, mites) H H H I moderate
paraffinic oil (JMS Stylet Oil) broad (exposed insects, mites) L L L II short
pyrethrin (PyGanic) 3A broad (insects) M M I short
petroleum oil broad (exposed insects, mites) L8 L L II short
pymetrozine (Fulfill) 9B narrow (aphids, whiteflies) L L L II short
pyriproxifen (Knack) 7C narrow (aphids, whiteflies) L H9 L II short
rosemary oil (Hexacide) broad (exposed insects, mites) L L L III
insecticidal soaps broad (exposed insects, mites) M M M II short
spinetoram (Radiant) 5 narrow (caterpillars, thrips, whiteflies, aphids, leafminers) L/M M10 L/M III moderate11
spinosad (Entrust, Success) 5 narrow (caterpillars, thrips, whiteflies, aphids, leafminers) L/H M10 L/M II short to moderate
spiromesifen (Oberon SC) 23 narrow (whiteflies) II
sulfur narrow (mites, thrips) L/H M/L H III short
thiamethoxam (Actara) 4A narrow (sucking insects) 12 M I moderate
H = high     M = moderate     L = low     — = no information
1 Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number morethan twice per season to help prevent 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 (un = unknown or uncertain mode of action) 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/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 Rating.
6 Duration: short means hours to days; moderate means days to 2 weeks; and long means many weeks or months.
7 May cause flare-ups of spider mite populations.
8 Rating depends on rate used.
9 Kills lady beetles.
10 Toxic against some natural enemies (predatory thrips, syrphid fly and lacewing larvae, beetles) when sprayed and up to 5-7 days after, especially for syrphid fly larvae.
11 Residual is moderate if solution is between pH of 7 to 8.
12 May cause increase in spider mite populations.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cucurbits
UC ANR Publication 3445

General Information

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.

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