The conventional pesticides applied to control them can lead to detectable residues, which growers are under pressure to reduce. This Defra Horticulture LINK project (TF 194) is investigating new biocontrol methods that researchers hope will fit in with existing non-chemical methods as part of an integrated pest and disease management programme.
Many samples of brown rot have been collected from four commercial orchards and their DNA compared to help scientists understand the sources of infection. About 200 yeast and bacterial strains, obtained from mummified fruit, are being tested for potential as biocontrol agents against brown rot. So far, five of these look promising.
The common black ant defends aphids against attack by natural predators, such as ladybirds, hoverfly larvae, earwigs, predatory bugs and spiders. If ants can be kept off fruit trees, aphids become less of a problem because these natural enemies control them. The project is looking at how to manipulate ant behaviour to control aphids - by distracting ants away from orchard trees to increase natural enemies there or by using ants to transport fungi that will attack aphids.
Other work in the project is investigating a sex-pheromone-based system for controlling plum fruit moth and light-brown apple moth. Biocontrol nematodes to control plum fruit moth are also being investigated.
Horticultural Development Company
For details on all HDC activity, visit www.hdc.org.uk