Industry Representative: James Wright, Whittern Farms
AHDB Horticulture Cost: £80, 740
Summary: Blackcurrant sawfly, Nematus olfaciens (Diptera: Tenthredinidae), is a common and frequently damaging pest of blackcurrant, present to varying degrees in all UK blackcurrant plantations. Infestation is sporadic and localised, and damage can occur rapidly. No practical systematic sampling methods or attendant crop damage thresholds have been developed and it is believed that there is widespread unnecessary treatment with insecticides leading to the risk of residues remaining in the crop. Adequate crop scouting is time-consuming and expensive, and a more sensitive and rapid monitoring method is needed. Pheromone traps could provide such a tool.
• Calibrate catches in the pheromone trap with field populations of blackcurrant sawfly in two generations (over 2 years) and determine factors (pesticides and natural predation) affecting this relationship
• Make trap commercially available with protocol for its use by growers including suggested thresholds for the two generations
Chlorpyrifos and thiacloprid are both very effective against sawfly but their future may be uncertain. Consumers’ desire for minimal, if not zero, residues of organophosphate materials is likely to limit or curtail the use of chlorpyrifos in the future.
Adequate crop scouting is time-consuming and expensive, and a more sensitive and rapid monitoring method is needed. More effective monitoring would help to make more cost-effective use of insecticides currently available with a likely reduction in their use. Monitoring will be vital for effective use of any more benign, biological approaches developed in the future. Pheromone traps could provide such a tool. Growers are generally familiar with this technology providing it is made readily available through commercial suppliers with adequate supporting information and protocols.