First doc­u­mented case of pest resis­tance to biotech cot­tonNature is wicked awe­some. Let me show you.

This story is about three organ­isms. First, we have cot­ton plants. Tasty, yummy cot­ton plants. Secondly, we have the boll­worm, aka Helicoverpa zea. Finally, we have a lit­tle bac­terium called Bacillus thuringien­sis which pro­duces a toxin that kills insects. We call that toxin Bt for short.

In 1996, some smart biol­o­gists decided to take the genes from B. thuringeien­sis that pro­duce those toxin pro­teins and insert them into the genome of the cot­ton plant (and pota­toes and corn too). This served to make the cot­ton plants not so tasty to the boll­worm. Tasty cot­ton plants become “ack-ack, plant of death!” to them. This was good because the cot­ton crop is worth $4.5 bil­lion annu­ally, and 70% of the dam­age caused to the crop is caused by cat­ter­pil­lars like the lowly bollworm.

All was well in the land of cot­ton for a while. But then in 2003, boll­worms were found eat­ing Bt-cotton plants! What gives? Evolution, baby!

Here are a few cool things about this. Places where bt-cotton is grown as a huge mono­cul­ture resulted in faster evo­lu­tion of bt-resistance in the boll­worm. Basically, the only boll­worms that could be found to mate with had a ten­dency to be resis­tant, and so you got really fast resis­tance in the over­all pop­u­la­tion. In places where boll­worms could end up on non bt-resistant plants, the resis­tance devel­oped much more slowly.

Now, of course the gengi­neers at Monsanto have upped the ante and pro­duced a cot­ton vari­ety that pro­duces two vari­eties of Bt-toxin. For now, the boll­worms are resis­tant to only one of those two. Soon, the sci­en­tists will develop another vari­ant that kills the resis­tant boll­worms and reset the clock.

So I looked it up, and the boll­worms have a life­cy­cle of 30 days. BT cot­ton went out in 1996, and in 2003, we have lev­els of resis­tance large enough that we see it. That means in roughly 72 gen­er­a­tions, H zea pop­u­la­tions devel­oped wide­spread resis­tance to the toxin.

There are two morals to this story. One: insects evolve really fast. Two: insects evolve resis­tance even faster when their envi­ron­ment is uni­formly poi­so­nous. Plant some nor­mal plants here and there to pro­vide refuges so that evolved resis­tance devel­ops slower.

Think about the above the next time you spray every­thing you own with antibac­te­r­ial soap.