Spent a fascinating evening learning about pesticides on Wednesday.
It was a programme of talks at Rothamsted Research (www.rothamsted.ac.uk) about how pests evolve resistance to pesticides (insecticides, fungicides and herbicides). It was really interesting set of talks, and there were around 150 people there to hear them.
One of the things that struck me is that natural selection – which we’re used to think of as a really gradual process – can be incredibly fast.
Think about a new herbicide which is fantastic at killing a particular weed. It’s so good that it kills 99% of the weed – with 1% having a slightly different genetic composition which for some reason makes it resistant. In season one the herbicide will be tremendous. But for season two the only seeds hanging around are going to be the ones from the 1% resistant variety, and they’ll have the field to themselves, more or less.
Natural natural selection may be slow and subtle, because minor advantages take some time to show their advantageous nature, but the fundamental principle can be seen from one year to the next, if you’re looking.
Well I thought it was interesting, anyway.