Plants produce a range of volatiles during their normal growth; these chemicals are used by plant feeding insects to locate suitable sites for feeding and reproduction. Recent work has focussed on identifying suites of plant volatiles which attract mated female gall midges to their host plants
for egg laying. Work focussed on three species – the raspberry cane midge, the blackcurrant leaf midge and the apple leaf midge. Suites of volatiles produced by all three host plants at the appropriate development stage and conditions for midge oviposition, were identified. Laboratory bioassays, wind tunnel and field work were used to assess the attractiveness of these chemicals to mated female midges with a view to producing lures which will be attractive to mated females in the field and thereby reducing midge populations.
Herbivore induced plant volatiles (synomones) have been shown to be attractive to some beneficial insects. Experiments were conducted to assess the attractiveness of synthesised plant volatile chemicals, to beneficial insects in pear orchards. Results indicated that syrphid flies were the main group of beneficial insects caught, particularly when using dispensers that included methyl salicylate or phenyl ethanol as volatile components. As generalist predators, syrphid larvae are likely to consume both aphids and pear psyllid nymphs and eggs, two of the most destructive pests in pear orchards, which would be valuable in an IPM programme.