Does the DEA use substances like "Agent Green"?

After sucessfully outdoor gardening in California for many years, a military helicopter hovered near my garden. Every since that it's been difficult to grow anything. The plants grow completely different and the bud is incredibly sparce and light.

I've tried everything from clearing out/disinfecting and starting new crops from known seeds to aquiring new clones, but it's been 4 years and many crops now and nothing seems to work. What ever the problem is it seems to be effecting a broad variety of species in the area, but seems most devistating to cannabis and vegetable crops.

I've done extensive testing both on my soils and water to no avail. As a last ditch effort I hired a professional pathologist to perform a site evaluation but I still haven't been able to find anyone who can identify the problem.

I suspect the chopper may have introduced something to the area that is effecting my crops. I've heard the DEA developed a cannabis destroying fungus called Agent Green, but I've never heard of it being used in California. Has anybody ever heard of anything like this?