Development of sex pheromone trap and evaluation of insecticides for control of blackcurrant leaf midge

Objective 1
• Red delta traps (not commercially available) with excluder grids at their entrances and held at a height of 3 cm above the ground on integral legs were optimal for trapping blackcurrant leaf midge using sex pheromone lures.
Objective 2
• For non-cut down bushes pheromone trap calibration showed weak positive relationships between numbers of gall per shoot and the total and peak catches of midge for the corresponding generation.
• For cut down bushes there was no relationship for either total or peak catches.
• More data is required.
Objective 3
• Five of the plant protection products tested gave at least some curative activity against existing infestations of larvae in galls (Dynamec, Gazelle, Equity, Brigade and Bayer product).
• Only the Bayer coded product and Brigade gave consistently reliable results.
• None of the products produced any visual symptoms of phytotoxicity.
Objective 4
• Timing of pesticide applications was critical in the control of blackcurrant leaf gall midge.  To be effective insecticides needed to be applied early in the generation of the midge (oviposition or early stage larvae).
• The Bayer coded product seemed to offer the best protection against the midge as it was equally as effect as Brigade in reducing the numbers of larvae, but also seemed to have a larger window of opportunity to apply the treatment.
• None of the treatments had any effect when applied at the end of the generation, probably because the larvae had completed development and left the gall, but also because the gall had become tough and necrotic, limiting any trans-laminar effects of the insecticides.
• None of the products produced any visual symptoms of phytotoxicity.

1. Field test the efficacy of the red delta trap prototype with and without excluder grids in comparison to a standard white delta tr
2. Examine the relationship between trap catches and numbers of galls formed in different commercial crops to establish a trap threshold
3.  Identify alternative chemical treatments to Brigade for the control of blackcurrant leaf midge. Seven alternative chemicals (mostly applied as foliar sprays) were compared to Brigade and an untreated control including abamectin (Dynamec), thiacloprid (Claypso), acetamiprid (Gazelle), spinosad (Tracer), Bayer novel product and chlorpyrifos (Equity as a foliar or soil treatment).
4.  Evaluate the efficacy of different timings of application of a novel Bayer product, Brigade and Equity for control of blackcurrant leaf midge utilising the sex pheromone trap. A single or double spray programme was compared to an untreated control.