SWDmonitoring tough for growers as search goes on for biological controlmeasures. By Judie Steeves
fforts are underway to design a bait that competes with ripening fruit for the attention of the Spotted Wing Drosophila, but at present, that is a monitoring issue frustrating for growers who find fruit infested before monitoring traps warn that they’re around.
It’s only an issue as fruit ripens, the critical time when growers need traps to alert them that the pest is on-farm. Prevention by proper sanitation remains one of the most important steps growers can take to ensure the crop is protected, but sprays are also crucial to prevent damage, advise entomologists.
Cooler spring and early summer weather the past two years has helped to reduce damage levels, and growers have been keeping it under control with a spray program.
Sheila Fitzpatrick, a researcher with the Pacific Agri-food Research Centre at Agassiz, recently attended a North American entomological society conference in Oregon and says SWD was a popular topic.
B.C. growers should be in better shape following last year’s cooler weather and late start to the insect’s reproduction cycle, she said, with lower numbers produced.
“Growers still need to be vigilant for it, though,” she added.
“We’re beginning to realize it is adapted to different growing areas and crops so one way of trapping and monitoring doesn’t necessarily work throughout B.C., Washington, Oregon and California,” she notes. Fitzpatrick believes there is some variation in how freeze-tolerant they
are, although they are found in houses and buildings over winter and probably don’t need to feed much while they overwinter. She called it a dark stage, when they don’t move around much and their metabolic rates drop. Once a crop is harvested,
JUDIE STEEVES Entomologist Sheila Fitzpatrick.
SWD appears to move to hedgerows and trees to overwinter. Dessication is an issue, and it tries to seek shelter where it can avoid drying out. Organic growers are those with the fewest tools to control the pest, she noted.
The search is on for more generalist predators that might be available and begin to prey on it, and different harvesting strategies can also be used. Entomologist Tracy Hueppelsheuser with the Plant Health Unit of the provincial agriculture ministry office in Abbotsford, says the ministry, in cooperation with the berry industry and
E.S. Cropconsult Ltd., has been trapping SWD all winter and expects the flies to be present again in 2012. She advises growers to keep track of developments on the ministry’s SWD webpage at:
For this year, she said growers should take the same approach as last year, using all tools: good sanitation, appropriately-timed insecticides and proper harvest timing and post-harvest management of fruit and fields. Emergency registrations are being requested to enable access to effective insecticides as needed, she said.
Stink bug alert continues
Fruit growers in the province are being urged to continue keeping watch for a potentially devastating insect pest.
Although the Brown Marmorated Stink Bug is not believed to be present in British Columbia, it has been confirmed in southern Washington and Oregon. Growers and homeowners are asked to bring any suspect stink bugs to the provincial agriculture ministry offices in Abbotsford or Kelowna.
Entomologist Tracy Hueppelsheuser explains that both adults and nymphs feed by inserting their needle-like mouthparts into the flesh of fruit or vegetables, causing punctures, corkiness, and death of tissues.
“Brown marmorated stink bugs can cause contamination in grapes, resulting in tainted wine. Many crops can be damaged, including berries, corn, peppers, tomatoes, apples, pears, grapes. Additionally this pest overwinters in buildings and homes in huge numbers.”
The adults are shield-shaped, 13-17 mm long. They have a brown marbled appearance, alternating brown and white markings on the outer edge of the abdomen and can be distinguished from other stink bugs by the presence of distinctive white bands on the antennae.
British Columbia Berry Grower • Summer 2012 19
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