Table of Insecticides and Miticides

Table¹ of common insecticides and miticides and their relative risk to honey bees. Never spray during bloom periods unless it is absolutely necessary. If treatment is unavoidable, choose a product with a high LD₅₀ and short residual. If a more toxic chemical is required, choose a residual under 8 hours and spray at night.

Active Ingredient	Trade Names	Risk Class²	LD₅₀³	Residual⁴
acephate	Orthene	I	1.2	1 day to >3 days
aldicarb	Temik	I	0.35	>1 day to >2 days
azinphos methyl	Guthion	I	0.43	2 days to >5 days
Bacillus thuringiensis	Biobit, Cutlass, Dipel, Javelin, Thuricide	III	NA	<2 hours
carbaryl	Sevin	I	1.5 to 26.5	<2 hours to 12 days
chlorpyrifos	Dursban, Lorsban	I	0.11	5 hours to 6 days
cyhexatin	Plictran	III	NA	<2 hours
cypermethrin	Ammo, Cymbush	III	NA	<2 hours to >3 days
diazinon	Diazinon	I	0.37	<1 day to 2 days
dicofol	Kelthane	III	NA	<2 hours
dicrotophos	Bidrin	I	0.3	1 day to 1 days
diflubenzuron	Dimilin	III	NA	<2 hours to 6 hours
dimethoate	Cygon, De-fend, Rebelate	I	0.19	<2 hours to >3 days
disulfoton	Di-syston	II	6.12	<2 hours to 7 hours
endosulfan	Thiodan	II	7.8	<2 hours to 1 day
ethion	Ethion oil	III	NA	<2 hours
fluvalinate	Mavrik	III	65.8	<2 hours
fonofos	Dyfonate	II	8.68	<2 hours to 6 hours
formetanate hydrochloride	Carzol	II	9.2	<2 hours to 2 hours
lindane	Lindane	I	NA	>2 days
malathion	Cythion, Malathion	I	0.73	<2 hours to 5 days
methamidophos	Monitor	I	1.37	4 hours to 1 day
methidathion	Supracide	I	0.24	day to 3 days
methomyl	Lannate	I	1.29	<2 hours to >1 day
methoxychlor	Marlate, Methoxychlor	III	NA	<2 hours
methyl parathion	Penncap-M	I	0.11 to 0.24	<1 day to >7 days
mevinphos	Phosdrin	I	0.3	<2 hours to <5 hours
naled	Dibrom	I	0.49	2 hours to >1 day
oxamyl	Vydate	II	10.3	<2 hours to 12 hours
oxythioquniox	Morestan	III	NA	<2 hours
parathion	Parathion	I	0.18	10 hours to >1 day
permethrin	Ambush, Permethrin, Pounce	I	0.16	12 hours to >3 days
phorate	Thimet	II	10.25	<2 hours to 5 hours
phosmet	Imidan	I	1.13	8 hours to >3 days
profenofos	Curacron	II	3.46	<2 hours to 9 hours
propargite	Omite, Ornamite	III	NA	<2 hours
sulprofos	Bolstar	II	7.22	<2 hours to >1 day
thiodicarb	Larvin	II	7.08	<2 hours
trichlorfon	Dylox, Proxol	III	NA	<2 hours to 6 hours

Table modified from Johansen & Mayer (1990) and Delaplane (1993).
Risk classes: I = highly toxic to honey bees, II = moderately toxic to honey bees, III = relatively nontoxic to honey bees. The risk class is closely associated with the LD₅₀.
LD₅₀ = the Lethal Dose required to kill 50% of the test honey bees, expressed in micrograms per bee. The smaller the LD₅₀, the more toxic the product.
Period of residual toxicity to honey bees after application. Evening applications of products with residuals of 8 hours or less generally cause only moderate harm to bees, even if the LD₅₀ is small. For example, mevinphos is very toxic to bees, but because it has a short residual, it is fairly safe for early evening applications.

top