WSU Tree Fruit Research & Extension Center

Spotted Wing Drosophila

Monday, March 25, 2019

News and Notes from the WSU Spotted Wing Drosphila Team for Tree Fruit

Program logs for 2015

Monday, June 8:

SWD trap captures continue high for this period of the year (even compensating for the early growing season and more effective lures), although lower than last week.  Pressure is evident from a number of early Drosophila finds in WSDA samples as fruit are brought to the packinghouse.  To date, WSDA has found Drosophila in commercial cherry samples from Mattawa, Zillah, Selah, and Grandview, as well north central Washington.

Also, the first western cherry fruit fly (WCFF) find has also been reported, so don’t forget about this important pest in your spray programs.  The materials that are effective on SWD are also effective on WCFF, but some materials, such as Provado and GF-102, are only effective on WCFF (they provide some suppression of SWD).

If you suspect you are in a high pressure area, keep weekly spray coverage, rotating materials between mode-of-action groups as necessary to stay on label.  This is primarily an issue for the spinosyns (Group 5) insecticides – Entrust, Success, Delegate, GF-120.  Consider a pyrethroid for this purpose.  Also, malathion and Sevin have short PHIs, but they also have a short period of residual activity.  Check the preharvest intervals before application.

Consider dimethoate as a postharvest sanitation measure.  If you don't want to damage foliage, fruit beneath the trees can be sprayed postharvest to kill developing larvae.

June 2:

Flies are active in the greater Wenatchee area as indicated by traps.  Low capture was recorded the 2nd week of May, and much higher numbers the last week of May.  These May catches were considerably higher than those caught (with the same lure) in June of 2014 – so, earlier and higher.  This is not unexpected given the extremely mild winter of 2014-2015, with only a minor cold spell last Nov/early December.

More importantly, infested fruit have also been found in the orchard at two sites on early-maturing cultivars, even though appropriate sprays had been applied.  The 2015 cherry growing season may be shaping up to have higher and earlier pressure than 2013, so plan accordingly.


North Central Washington:
Tianna DuPont

Extension Regional Specialist
1100 N Western Ave
Wenatchee, WA 98801
(509) 663-8181 x211
FAX: (509) 662-8714

Columbia Basin:
Gwen Hoheisel

Extension Educator
1121 Dudley Avenue
Prosser, WA 99350
(509) 786-5609
FAX: (509) 786-5525

Tree Fruit - statewide
Elizabeth Beers

1100 N Western Ave
Wenatchee, WA 98801
(509) 663-8181
FAX: (509) 662-8714

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Tree Fruit Research & Extension Center, 1100 N Western Ave, Washington State University, Wenatchee WA 98801, 509-663-8181, Contact Us