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Not as easy as you might think. Insects can be devastating to crops, and even with pesticides losses are still high, in many cases as much as 1/3rd. To make matters worse, insects take a relative “horse dose” of insecticide to kill them, and distribution on plants is never even, so some plants get a lot, as some plants very little if any.

One of the pesticides used for a long time are the organophosphates, which are essentially akin to military nerve agents, but weaker. Parathion, one of these popular with crops, has a Lethal Dose for 50% (LD/50, a standard measure) of a group of *humans* of only 6,000 ppm. The military chemical weapon phosgene has an LD/50 of about 9,000 ppm, so it is actually weaker than this pesticide. Crop duster pilots who use Parathion have to wear whole body space suits with a filtered air supply.

The pesticide sprayed on the public in California, to combat the Medfly was a weaker type of organophosphate called Malathion, which still has an LD/50 of about 30,000 ppm.

Insect resistance to pesticide also increases over time, so between that and the relentless federal effort to stop the use of any effective pesticides, farmers are fighting a losing battle.

There is now growing reliance on trying to combat insects in different ways, such as breeding and releasing radiation sterilized insects that will mate with wild insects but not produce offspring, and also to create and cultivate insect diseases that will wipe out vast numbers of insects in epidemics.

Yet so far these have only worked on a limited basis and for single species of insects. Thus we have no choice but to continue to use pesticides, some of which kills bees.