2012 - Washington Red Raspberry Commission

Project No.: 13C-3443-5370
Title: Chemical control of spotted wing drosophila, Drosophila suzukii (Matsumura) in western
Washington red raspberry, utilizing local monitoring and phenology between fruit ripening and
infestation levels
Year Initiated: 2009 Current Year: 2010-2011 Terminating Year: 2012
Personnel: Lynell K. Tanigoshi, Entomologist 1
Beverly S. Gerdeman, Research Associate, Entomology 1
G. Hollis Spitler, Agricultural Research Technician 1
Collaborators: Thomas Walters, Small Fruit Horticulture Program 1
1 WSU-Mount Vernon NWREC
Accomplishments: Two follow-up field residual trials design to corroborate and clarify 2011
mortality levels for SWD adults, failed to provide statistically significant results that provided
growers with general guidelines for their insecticide rotations within and between different MOA
chemistries. Results indicated 50 ± 23.3 percent adult mortality for Mustang Max at 1 DAT and
no mortality at 8 DAT is extremely problematic. Study of the ovarian development of SWD
provided new knowledge about the seasonal reproductive status of fluctuating SWD populations
in northwestern Washington. Presence of SWD in the field did not always coincide with egglaying
capacity. Topical applications of Brigade, Mustang Max, Actara and experimental
Voliam flexi and Cyazypyr provided a high level of clay colored weevil mortality/morbidity by 4
DAT. The latter new MOA chemistry is more effective when ingest by root weevils when they
encounter continued exposure to dried residues on fruit or foliage under field conditions.
Cyazypyr will be supported for an IR-4 residue project.
Results:
Field-aged residual trials for SWD control
Field aged insecticide residual studies were conducted on foliage similar to our 2011 trials to
measure adult SWD contact mortality on primocane foliage. We feel residues on foliage are
better indicators of potential mortality rates than on fruit surfaces. Canopy foliage provides
larger surface areas for high-pressure sprayer coverage that will mitigate resting and feeding sites
for adults between their egg-laying activity. Applications were applied with a Spray Systems®
CO 2 backpack sprayer equipped with a 36 inch boom equipped with 4 TeeJet® 8002VS flat fan
nozzles. This unit will deliver 96 gal/acre to run off at 40 psi. All applications included the
adjuvant MSO at 0.0025% v/v. Eleven treatment applications were applied in a 3’ x 9’ swath at
chest height on the westside of 10’x9’ plots. Treatments were made on 16 and 28 August 2012
in a 7 year-old ‘Meeker’ field at the WSU REC, Mount Vernon. Posttreatment evaluations were
made by sampling 4 random, mature primocane leaflets per plot from the spray swath. A leaflet
was placed topside up in a disposable 100x15 mm Petri dish with a moisten cotton dental wick, 5
mm 3 of diet media and 5 even-aged SWD adults from our lab colony. These replicated treatment
units were evaluated for adult mortality after 24 hr. Random leaf cohorts were taken daily out to
8 days for the multiple treatments and exposed to new SWD adults until