CNN this morning was running a segment on “green” lifestyles and during it they made the comment that “cotton accounts for 2% of the crops grown in the world but 25% of world pesticide use”.
This number sounds completely wrong to me. I would have assumed that food crops would naturally have more pests than a non-food crop like cotton (and before anyone points it out to me, I do know what a boll wevil is) and would therefore account for a higher percentage of pesticides. I’ve tried checking Google but I’m getting way too many pages to be useful and my Google-fu is failing me today. So, does cotton farming really use that much insecticide?
Well, i remember reading a couple of books on sustainable agriculture a few years ago, and they both made the claim that cotton uses a drastically disproportionate amount of the world’s herbicides and insecticides. I can’t remember the numbers in those books, but i remember being staggered at how high they were.
Regarding your point about food crops, remember that insect pests don’t necessarily consume the same parts of the plants as humans do, and that there are plenty of insects (not just the boll weevil) that can have a detrimental effect on cotton crops. Also, remember that the more general term pesticide can include herbicides and fungicides, so it’s not just insects that they’re trying to drive away.
It’s mostly because of insects. Weeds aren’t that much more of a problem for cotton than they are for any other crop. But it’s not a problem of hybridization. insects have always eaten cotton.
Cotton growers don’t want to spray insecticides that have any kind of "persistence) (a long period of effectiveness) – the same poisons that kill the bugs can also kill you if you go back into the field before they’ve broken down. And nothing kills 100% of the pests the first time.
So you constantly have bugs that are not only eating the crop, they’re also laying eggs which hatch into more bugs that eat the crop. As a result, you have to keep spraying the same field over and over again, sometimes 6 times in two months during the height of bug season.
The growers rotate treatments, so they don’t overuse a single type of insecticide, and yes, they use what they call “botanicals” (ladybugs and other natural predators.) But there’s still a lot of spraying during the typical growing season.
For the past several years, as I drive past the cotton fields in West Texas, I’ve been seeing these little green plastic bottles on fence posts, every few hundred yards. Finally a year or so ago, I looked up what they are. They’re part of the Boll Weevil Eradication Program (which you can Google). The goal of this program is, of course, eradication of the boll weevil, with the side benefit that much less pesticide is required. These green bottles have some pheremone so some such chemical that’s attractive to boll weevils (the males I think), and are monitored frequently. If a field is found to have boll weevils, the farmer nukes the hell out of the field with pesticides. Otherwise, they don’t use pesticide. The program has apparently wiped out the boll weevil in several Southeastern states, and Texas is next.