Agriculture: Onion and Garlic Pest Management Guidelines

Relative Toxicities of Insecticides and Miticides Used in Onion and Garlic 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 (leafminers, mites, thrips) M L M/H I moderate to predatory mites and affected insects
azadirachtin (AzaGuard) un broad (insects, mites) M L/M L/M II short
Beauveria bassiana (Mycotrol) broad (insects) L L/M L II
chlorpyrifos (Lorsban) 1B broad (insects, mites) M H H I moderate
clothianidin/imidacloprid (Sepresto) 4A broad (insects) L/M L/M I
cyromazine (Trigard) 17 narrow (leafminers) L L L II none
methomyl (Lannate) 1A broad (insects, mites) H H H I moderate
spinetoram (Radiant) 5 narrow (aphids, caterpillars, leafminers, scales, thrips, whiteflies) M M8 L/M II moderate7
spinosad (Entrust, Success) 5 narrow (leafminers, thrips) M M8 L/M II short to moderate
5/4A broad (insects)
spirotetramat (Movento) 23 narrow (aphids, psyllids, scales, whiteflies) L L L II short
H = high      M = moderate      L = low      — = no information      un = unknown or uncertain mode of action
1 Rotate insecticides 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 development of resistance. For example, the organophosphates have a group number of 1B; insecticides with a 1B group number should be alternated with insecticides 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.
4 Toxicities are averages of reported effects and should be used only as a general guide. Actual toxicity of a specific insecticide depends on factors including the application rate, environmental conditions, and life stage and species of the parasite or predator.
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 pesticide label and regulations; III–No bee precaution, except when required by the pesticide 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 Residual is moderate if solution is between pH of 7 to 8.
8 Toxic against some natural enemies (predatory beetles, lacewing larvae, syrphid fly larvae, and predatory thrips) when sprayed and up to 5 to 7 days after, especially for syrphid fly larvae.

Acknowledgments: 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: 10/18