Strawberry Crown Moth Control in Strawberry

L. K. Tanigoshi and J. R. Bergen
Washington State University
Vancouver Research and Extension Unit
Vancouver, WA 98665-9752

Strawberry crown moth, Synanthedon biblionipennis, was collected on 15 and 21 July 2004 near Richfield, WA in a 4 year-old ‘Totem’ field. Adults were actively mating and eggs were found attached to leaves as well. Adults were collected with sweep nets, cups, baseball caps and persistence. Collections were taken to the lab and promptly prepared for exposure to 3 experimental compounds and compared with field rates of Brigade and Success. A leaflet was sprayed with our Precision Potter Tower, placed in a 5.5 oz. plastic cup with one strawberry crown moth. The plastic lid was perforated and mortality examined daily for 4 days. A honey and water solution was provided for each moth in saturated sections of a dental cotton wick. Fifteen moths were used for each treatment on 15 July and 10 moths each for the 21 July treatments.

Capture (bifenthrin) provided 93% mortality of adult strawberry crown moths at 24 hours posttreatment and complete mortality after 2 days (Table 1). The neonicotinoids Actara (thiamethoxam) and Assail (acetamiprid) provided significant contact activity at 3–4 days posttreatment to this clear winged moth (Tables 1, Table 2). The performance for Success (spinosad) in the 21 July bioassay was comparable to the results observed for Capture. However, the poor results obtained for the 15 July bioassay were not expected given its known activity against Lepidoptera. Avaunt’s (indoxacarb) activity was somewhat intermediate to the other known insecticides in this preliminary lab bioassay (Table 1). We will lab and field trials these excellent compounds next season. This insect has become a significant problem in the Richfield strawberry area of Clark County in the past 3–4 years.

Table 1. Strawberry crown moth bioassay.

Treatment	lb(AI)/acre	Percent Mortality
		1DAT	2DAT	3DAT	4DAT	5DAT
Mean within columns followed by the same letter are not significantly different (Tukey HSD test,P<0.05).
Actara 25WG	0.094	0.33b	0.53b	0.60b	0.93a	1.0a
Assail 70WP	0.25	0.20b	0.47bc	0.80ab	0.93a	1.0a
Success 2SC	0.094	0.27b	0.33bc	0.53b	0.60b	0.87a
Avaunt TM	0.11	0.27b	0.40bc	0.73ab	0.73ab	0.93a
Capture 2EC	0.10	0.93a	1.0a
Untreated check		0.07b	0.07c	0.13c	0.4b	0.40a

Table 2. Strawberry crown moth bioassay.

Treatment	lb(AI)/acre	Percent Mortality
		1DAT	2DAT	3DAT	4DAT	5DAT
Mean within columns followed by the same letter are not significantly different (Tukey HSD test, P<0.05). Treated 21 July 2004, 10 reps.
Actara 25WG	0.094	0.70a	0.80a	0.90a	0.90a	1.0a
Assail 70WP	0.25	0.80a	0.80a	0.90a	1.0a
Success 2SC	0.094	0.70a	1.0a
Untreated check		0.10b	0.10b	0.20b	0.30b	0.60b