Agriculture: Alfalfa Pest Management Guidelines

Relative Toxicities of Insecticides and Miticides Used in Alfalfa 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
Bacillus thuringiensis ssp. Aizawai (XenTari) 11A narrow (caterpillars) L L L II short
Bacillus thuringiensis ssp. Kurstaki (Javelin) 11A narrow (caterpillars) L L L III short
beta-cyfluthrin (Baythroid) 3A broad (insects, mites) H H H I moderate
chlorantraniliprole ( Vantacor) 28 narrow (primarily caterpillars) L L L/M III short
Dimethoate (Dimethoate 400 EC) 1B broad (insects, mites) H H H I long
flonicamid (Beleaf) 29 narrow (aphids, lygus bugs) L L L III short
flupyradifurone (Sivanto) 4D narrow (aphids, leafhoppers) I
hexythiazox (Onager) 10A narrow (mites) M L L II short to moderate
indoxacarb (Steward) 22A narrow (caterpillars, lygus bugs) L L I moderate
lambda-cyhalothrin (Warrior II) 3A broad (plant bugs, beetles, caterpillars) H H H I moderate
Malathion (Malathion 8-E) 1B broad (insects, mites) H H H I moderate
methomyl (Lannate LV) 1A broad (insects, mites) H H H I moderate
methoxyfenozide (Intrepid) 18 narrow (caterpillars) L L L II short
neem oil (Trilogy) broad (soft-bodied insects) L L L II short
permethrin (Pounce ) 3A broad (insects, mites) L H H I long
spinosad (Entrust) 5 narrow (weevils) M M7 L/M II short to moderate
zeta-cypermethrin (Mustang) 3A broad (insects, mites) H M 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 more than 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 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 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 Toxic against some natural enemies (predatory thrips, syrphid fly and lacewing larvae, and beetles) when sprayed and up to 5 to 7 days after, especially for syrphid fly larvae.
Text Updated: 04/24