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Blueberry Aphid Bioassay on Blueberry, 2008

BLUEBERRY APHID BIOASSSAY ON BLUEBERRY, 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
bbA2Blueberry aphid, Ericaphis fimbriata (Richards).  A population of alate blueberry aphids was collected on 17 July from a varietal blueberry planting at the WSU Mount Vernon NWREC.  Terminal leaves were individually, placed top-side-up, between 3.5” x 7.5” cotton absorbent/lint-free pads.  The pads were folded in half with the top half containing a 1.2” diameter circle formed from a cork punch.  This unit was placed in a 5” diameter plastic Petri dish and saturated with water to form a water barrier around the arena.  Between 10-13 wingless, blueberry aphids were carefully placed in the arena with a 00 camel hair brush and allowed to settle before topically treated to wetting with a hand held atomizer with the aphicides listed below.  These arenas were held under laboratory conditions.  Compared with the untreated check, all treatments were significantly different at the 5% level througBBAh 11 days posttreatment (Table 1).  Both rates of Assail 70WP provided quick knock-down of blueberry aphid within 24 hours of their exposure.  Experimental Movento™ (spirotetramat) “2-way systemicity” and unique mode of action via ingestion provided complete population mortality by 8 DAT for both rates tested.  Movento has been shown to provide excellent residual out to 21 DAT.  Movento must be applied as aphid population begins to increase because it is not curative.  Experimental Cyazypyr (DPX-HGW86) has a ryanodine receptor activator mode of action, is translaminar via foliar application, is systemic via root uptake and induces cessation of feeding when ingested.  The latter symptom was observed with two formulations and four treatments after 1 DAT, though complete population mortality was delayed to or through 11 DAT.

Table 1.  Blueberry aphid leaf bioassay on blueberry, 2008.

Percent Mortality


Treatment

Rate/acre

1 DAT

3 DAT

5 DAT

8 DAT

11 DAT

HGW86 10SE*

13.6 fl oz

32b

24cd1

77abc

91a

97a

HGW86 10SE*

20.6 fl oz

3c

27cd

55c

67b

74b

HGW86 10SE* + MSO

13.5 fl oz

23bc

40cb

71bc

87a

100a

HGW86 OD*

13.5 fl oz

10bc

42cb

74abc

90a

91ab

Assail 70WP

1 oz

100a

Assail 70WP

2.3 oz

100a

Movento 240SC + Dyne-Amic

5 fl oz

22bc

61b

84ab

100a

Movento 240SC + Dyne-Amic

8 fl oz

8bc

39cb

81abc

100a

Untreated check

0c

3d

3d

4c

20c


Mean within columns followed by the same letter are not significantly different (Fisher’s protected LSD, P<0.05), PRC ANOVA SAS.
MSO, methylated seed oil adjuvant; SE, suspo emulsion; OD, oil dispersion.
*Buffered to a pH of 5 or lower.

1Live females may produce progeny between sampling periods <% mortality over time.