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WESTERN RASPBERRY FRUITWORM ON RED RASPBERRY, 2008

WESTERN RASPBERRY FRUITWORM ON RED RASPBERRY, 2008

L. K. Tanigoshi, B. S. Gerdeman and G. Hollis Spitler
Washington State University
Mount Vernon Northwestern Research and Extension Center
Mount Vernon, WA  98273-4768
360-848-6152
tanigosh@wsu.edumitehunter1@hotmail.comspitler@wsu.edu

Western raspberry fruitworm, Byturus unicolor Say.Two recommended rates for the recently registered systemic neonicotinoid Assail™ 70WP (acetamiprid) were compared with Brigade™ (bifenthrin) and BASF’s experimental BAS 320 I formulation, to control the adult western raspberry fruitworm.  Residual leaf dip bioassays were conducted using raspberry leaves whose stems were insertedtable into water-filled vials and plugged with cotton.  Individual trifoliate leaves were dipped in respective deionized water-insecticide solutions for 5 sec air dried and placed in 5-inch diameter Petri dishes.  Each treatment was replicated seven times.  B. unicolor adults were collected on 23 June from a mature ‘Totem’ field in Lynden, WA.  Three adult western raspberry fruitworm adults (Fig. 1), collected in mid-June, were each placed into five arenas and six each in the 6th arena and maintained at room temperature.  Adult mortality was to be evaluated every 24 hours (Table 1).

Within 24 hours, 100% mortality was observed for adult beetles exposed to Assail and Brigade.  All of the adults exposed to BAS 320 I leaves were in a moribund state.  They were all observed on their backs, appendages moving while unable to right themselves, exhibiting diarrhea and females involuntarily laying eggs.  We scored these adults in the mortality category because of their moribund state.  We conclude that the insecticides currently labeled for caneberries will effectively control western raspberry fruitworm.

Table 1.  Adult western raspberry fruitworm bioassay, 2008.

Percent Mortality

Treatment

lb(AI)/acre

1DAT

Assail 70WP

0.083

100a

Assail 70WP

0.10

100a

BAS 320 I

0.10

100a

Brigade WSB

0.10

100a

Untreated check

0b

Mean within columns followed by the same letter are not significantly different (Fisher’s protected LSD,P<0.05), PRC ANOVA SAS.