Question

1. Not all neonicotinoid insecticides are hazardous to bees owing to a combination of comparatively high LD50s and also use of low field rates. Which insecticide in the following list would be the least toxic to honey bees.

a.imidacloprid

b.clothianidin

c.sulfoxaflor

d.acetamiprid

e.2,4-D

f.diuron

g.chlorpyrifos

2. Given the route of exposure scenarios for bees developed by the EPA for pesticides in its conceptual model for systemic foliar applied pesticides, what is the single most effective method (or practice) for ensuring minimal bee toxicity when a field or orchard must be sprayed to control insect pests. State your prescription in one sentence, starting with the phrase, “Never spray insecticides when….” [______________________________________________]

3.The DT90% for Cry3Bb1 protein ranges from 9.2 to 50 days that is dependent on which two of the following scenarios.

a.Soil temperatures are above 80 deg F

b.Moisture content of soil exceeds 50% of maximum saturation

c.Bt corn stalks are incorporated into the soil

d.Purified proteins is added to the soil

e. Corn rootworms are present to degrade the insecticide

Answer 1

1. All insecticides kill insects none have been invented that are harmless to bees, though some are more harmful than others. Acetamiprid are much less toxic to bees than the other neonics, so it is less toxic & they are safe for bees.

2. Never spray insecticides directly over colonies of bees.

3. The DT90% for Cry3Bb1 protein ranges from 9.2 to 50 days that is dependent on two of the following scenarios.

• Bt corn stalks are incorporated into the soil
• Moisture content of soil exceeds 50% of maximum saturation