Pink cotton bollworms on cotton boll. Image credit:excerpted from image onWikipedia
Mass release of sterile crop pests can be a practical control strategy (presumably even for organic farmers). As reported by SciDevNet, 'release of sterile insects has successfully lowered populations of the Mediterranean fruit fly in Guatemala, Mexico and the United States; screw-worms in Central America, Libya and the United States; and tsetse flies in Zanzibar.'
US cotton farmers - the ones raising GM cotton with the Bt gene inserted - have asked permission of USEPA to release sterile pink bollworm moths into their Bt cotton fields. This tactic would be in lieu of having to plant contiguous acres of non-Bt inserted cotton as a means of preventing Bt resistance development: a substitute for the so-called "refuge" planting typically required of those who use Bt cotton.
To prevent the spread of resistance to Bt among the bollworm, farmers are required to plant refuges of conventional cotton nearby. These harbour moths that will mate with any resistant moths that emerge among the Bt plants to prevent resistance developing.
However, farmers have started to resent the refuges because they also allow the bollworm to persist -- costing them millions of dollars annually in crop losses and insecticide sprays.
They therefore asked the US Environmental Protection Agency for permission to dispense with the refuges and instead begin releasing sterile moths, which then conducted mathematical modeling that showed such a strategy could indeed work.
No freaking out!
If I were a cotton farmer I'd ask for the same permission - regardless of whether I grew Bt cotton or a traditional, non-Bt variety. It's a strategy that makes both ecological and economic sense. After all, the pink boll worm is another one of those Asian invaders no ecosystem in America needs.
Let's suppose the sterile moth releases are shown to be capable of eliminating the pink boll worm moth from US cropland. For Monsanto, that could be a market destroyer. There may be no alternative, however, but for Monsanto to go along with the release programs if, as indicated a Wikipedia entry on the bollworm, "Monsanto has admitted that this [Bt cotton} variety is ineffective against the pink bollworm pest in parts of Gujarat, India." and if the resistance spreads around the world.
Side-benefit of climate change mitigation.
I'm not gong to pass up another good chance to stir the pot. Like the irony of tea drinkin' Republican Governor opposed to biomass fuel, this sterilization tactic is rich with possibilities.
One of the methods an organic cotton farmer might use to minimize moth populations next year is to burn this year's cotton plants, post-harvest. There are a few environmental problems with that approach:
- air quality problem for neighbors, check.
- increased carbon footprint of organic cotton, check.
- increased soil erosion, check.
So...what do you say? Release sterile bugs or not?
More posts on Bt resistance.
Genetically Modified Cotton Associated With Increased Plant Bug ...
Cotton Bollworm Shown To Resist Bt Produced By Transgenic Cotton ...
Organic Exchange Responds to GMO/Organic Cotton Controversy ...