Predatory beetle may control pear suckers

Jerry Cross, an entomologist at East Malling Research, told delegates at last week's pear conference in Kent that the pear sucker could be devastating, forcing growers to rip up heavily infested orchards. But a four-year HortLink project has identified a bio-control: the predatory beetle Anthocoris nemoralis.

"Anthocorid bugs are powerful predators of pear sucker and can naturally regulate populations," he said. "But they do not overwinter in orchards in enough numbers, while spring influxes are often too late."

However, during the early season, a lot of the bugs were found in hawthorn, grey and pussy willow, hazel and nettles.

"These were the best species for conservation bio-control of pear sucker. Hawthorn is potentially excellent but could be a source of fireblight if not carefully managed."

Many pear orchards were surrounded by Italian alder windbreaks, which looked good but were "pretty useless" in managing pear sucker.

Growers often used chemical sprays but treatments were not evidence-based and their effects on anthocorids were unknown. Early lab tests suggested sulphur and magnesium sulphate had little short-term effect.

Meanwhile, East Malling Research was looking to roll out another HortLink project, on water research, to a grower site this year.

EMR irrigation expert Mark Else said 85 per cent of UK growers worked in "water-stressed areas", but careful reduction of irrigation had benefits.

"It can reduce shoot growth by 30 to 40 per cent and therefore lower pruning needs. Less foliage can mean less disease and more light penetration. There is potential for large savings through sustainable production, high water-use efficiency, targeted application and use of fertiliser. Risks include lower yields and smaller fruit."