I have long been fascinated by the way greenfly will populate one type of chilli plant but not another, and while chilli plants are generally a tasty target, greenfly are happy to dig into one variety while another variety next door goes unscathed, at least for a while.
Some years I get very little in the way of greenfly, other years, like this one they are more of a challenge but even though they are pest, I still find them strangely fascinating. Their breeding cycle is weird, some are born with wings, some without, and some are even born pregnant.
So I have been observing their progress recently. A few weeks ago i noticed a few on my Chilhuacle negro plants, but not any of the others. Now they have spread a bit, firstly to bhut jolokias, but not Carolina reapers, then to some cajun belles, then to some aji, and yet the pimiento de Padron in-between remain untouched.
An entomologist once told me that that they tend to stick to one variety if they can and so in my greenhouse I dispensed with keeping plants of the same variety next to each other, now I alternate them, so that if one plant is infected with greenfly then they are less likely to jump onto the neighbours. Apparently they just get used to the sap of one plant, and their young will prefer to stay there. They still managed to spread from one chilhuacle to another, but it took a while, the fact that they were spread out bought me some time to squash them.
Anyone done any serious experimentation on this?