Soft-fruit growers should consider a wide range of measures to reduce pesticide residue on crops, according to Professor Jerry Cross, research leader at East Malling Research.
Outlining the results of two five-year Horticulture LINK studies on controlling the main pests and diseases affecting raspberries and strawberries, he said: "It was found that Botrytis can be controlled on raspberries by optimising cane density and keeping down humidity in the canopy, while rapid heat removal after picking meant there was no need to spray fungicide during flowering.
"And apart from one spraying in October, aphids could be dealt with by biological controls."
He added that strawberry beetle could be controlled effectively through the use of monitoring traps. "You only need to spray when a threshold number is found," he said, adding that other measures looked at included "bug-vacs" and pheromone controls.
Explaining the problem, he said: "There is a high incidence of residues on soft fruit. It is the spraying between flowering and fruiting that leads to residues. You can't eliminate residues, but you can greatly reduce them."
Cross added that although such residues seldom exceed legal limits, they are often at reportable levels. "It's not a food safety issue, but the supermarkets don't like it," he said. This has particularly been the case since the sources of such samples have been "named and shamed" in surveys, he added.
Last year, a Government survey of 96 retail samples found that only 11 contained no residues, while some contained traces of up to 10 separate chemicals.
"They were generally only around 10-20 per cent of the maximum, but one was at maximum residue level," Cross said.
Soft Fruit Day
East Malling Research leader Professor Jerry Cross will discuss the studies' findings at the East Malling Research Association/Horticultural Development Company (HDC) Soft Fruit Day on Wednesday 23 November in Kent.
The meeting will also look at other novel controls for pests and diseases, as well as water-use issues and recent developments in breeding.
To attend, call Kirsty Nichols at HDC on 02476 478677.