Industry representative: John Evans, JA Colthup & Partners
HDC project cost: £34,088
Apple aphids are an ongoing pest problem, and biological control can help to reduce the severity of attack or eliminate the pest problem. Hoverfly larvae are voracious predators of aphids and if adults can be attracted into the orchard early in the season, and/or encouraged to overwinter in or close to orchards, this increase in predators would be an important component of an IPM strategy. Hoverflies overwinter either as adults or pupae depending on the species. Biocontrol is particularly effective where ants are discouraged from protecting the aphids. Hoverfly adults respond to plant produced volatiles and to components specific to aphid feeding. Therefore, dispensers containing synthesised plant volatiles will be assessed in replicated field experiments in apple orchards to assess the potential attractiveness of these chemicals to hoverflies. If successful these will be combined with visual cues which are also known to attract hoverflies.
Aims and objectives:
2) To determine whether increasing populations of adult hoverflies in the autumn will lead to increases in hoverfly populations in the orchard in the spring
3) To determine the degree to which increases in hoverfly populations reduce aphid populations in the orchard
• The use of plant volatiles to attract beneficial species is compatible with IPM and organic control programmes in apple orchards
• If successful we will be able to manipulate beneficial species numbers in orchards with the aim of ultimately reducing pest numbers
• Attraction of hoverflies into orchards would also be economically favourable as they are important pollinators and are reported to be the most important pollinator group after wild bees.