Lead researcher Dr Ben Raymond at Royal Holloway University of London said: "We found that our strain, ST8, is the most common in the environment already and it also seems to be best at getting onto the leaves where it can infect the moths. We think that the ST8 that exists naturally in the farm environment might well be colonising the plant as growing seedlings so it gets the earliest possible opportunity to infect the moths, which of course it needs to do to survive.
"This makes sense given that we also found that when there are extra insects in the environment the bacteria actually do much better and can be found in larger numbers. It also shows why spraying the plants, especially young ones, rather than the soil is the best way of using Bt to control insect pests."
The research team are also looking at factors that affect the chances of insects becoming resistant to Bt. In particular they are looking at the way the toxin that kills the insect and an antibiotic that Bt produces to get rid of competing strains of bacteria in the insect's gut both impact the evolution of resistance in the insect.
Professor Douglas Kell, BBSRC Chief Executive said: "Sustainable solutions to future food security will rely on a thorough understanding of how ecosystems operate. This is a good example where the interactions between different parts of such a system have a significant impact on how we can control pests using biological rather than chemical methods. It is also vital that our ongoing practices with Bt present minimal risk of insects becoming resistant and so work to understand the fundamental biology that happens within this system is extremely important."
|Contact: Nancy Mendoza|
Biotechnology and Biological Sciences Research Council