Washington State University
Vancouver Research and Extension Unit
Vancouver, WA 98665-9752
Winter moth, Operophtera brumata (L.) and Bruce spanworm, O. bruceata (Hulst) have increasingly been reported as economic, early season pests of blueberries grown in Oregon and Washington. The eggs of both species are laid during late fall and early winter. Growers often missed detection of the early hatch of these emerging moths in March to mid-April when temperatures average about 55 °F. Larvae are difficult to control because the first instar larva will burrow into and feedon unopened buds. Maturing larvae are difficult to detect until they have migrated from bud to bud and visible damage has occurred to these fruiting bodies and surrounding foliage. Winter moth larvae were collected from opening fruit buds in mid-April from Woodlands, WA and from English Laurel foliage in mid-April from Whatcom County . Six reduced risk products were tested and compared with Diazinon and Capture standards. Insecticides were applied in aqueous suspensions using a Potter Spray Tower with 2 ml of each concentration applied to 4 inch blueberry fruiting twigs. These were air dried, placed in a water-dental wick-vial in a 6 inch Petri dish held at lab temperature with one winter moth. These replicated trials were observed 5-6 days after treatment for larval mortality.
For 2 of the 3 Potter tower bioassays, bifenthrin (Capture®) at the red raspberry and strawberry rate of 0.1 lb(AI)/acre expressed 100% mortality after twenty-fours posttreatment. Bifenthrin shows an excellent potential use on blueberry for larval Lepidoptera and root weevil. Secondly, the synthetic avermectin analogue Proclaim® showed excellent control of winter moth larvae both after twenty-fours hours and 100% mortality at either 5 or 6 days posttreatment. This compound was also given potential use status on the IR-4 new products/transitional solution list, July 2002. Indoxacarb (Auvant®), the recently registered spinosad (Success®) and the insect growth regulator methoxyfenozide (Intrepid®) performed consistently well at several rates, especially after 2-6 days posttreatment. All three of these compounds are considered reduced risk products and Auvant and Intrepid have been given pending use status for blueberry by IR-4. Generally, the other insecticide tests showed significant differences from the untreated check in most cases 5 days after treatment (Table 1, Table 2, Table 3).
Treatments | lbs(AI)/acre | Percent Mortality | ||
---|---|---|---|---|
1DAT | 2DAT | 5DAT | ||
Percentages within columns followed by the same letter are not significantly different (Tukey HSD test, P<0.05). | ||||
Avaunt WG | 0.09 | 40ab | 40bc | 60a |
Intrepid 2F | 0.25 | 60ab | 80ab | 100a |
Proclaim 5SG | 0.01 | 100a | 100a | 100a |
Success 2SC | 0.10 | 80a | 100a | 100a |
Untreated check | 0b | 0c | 0b |
Treatments | lbs(AI)/acre | Percent Mortality | ||
---|---|---|---|---|
1DAT | 3DAT | 6DAT | ||
Percentages within columns followed by the same letter are not significantly different (Tukey HSD test, P<0.05). | ||||
Actara 25WG | 0.086 | 0a | 20ab | 100a |
Avaunt WG | 0.045 | 0a | 20ab | 100a |
Avaunt WG | 0.11 | 0a | 40ab | 100a |
Capture 2EC | 0.10 | 40a | 100a | 100a |
Intrepid 2F | 0.12 | 20a | 40ab | 100a |
Intrepid 2F | 0.25 | 0a | 0b | 100a |
MVP II | 0.50 | 60a | 60ab | 100a |
Proclaim 5SG | 0.008 | 40a | 60ab | 100a |
Proclaim 5SG | 0.015 | 0a | 0b | 100a |
Success 2SC | 0.019 | 40a | 80ab | 100a |
Success 2SC | 0.049 | 40a | 40ab | 100a |
Untreated check | 0a | 20ab | 20b |
Treatments | lbs(AI)/acre | Percent Mortality | ||
---|---|---|---|---|
1DAT | 2DAT | 5DAT | ||
Percentages within columns followed by the same letter are not significantly different (Turkey HSD test, P<0.05). | ||||
Actara 25WG | 0.086 | 73abc | 80a | 87a |
Avaunt WG | 0.09 | 73abcd | 100a | 100a |
Avaunt WG | 0.045 | 60abcd | 87a | 93a |
Avaunt WG | 0.065 | 67abc | 73a | 93a |
Avaunt WG | 0.11 | 53abcd | 93a | 93a |
Capture 2EC | 0.10 | 100a | 100a | 100a |
Diazinon 50WP | 0.50 | 80abc | 87a | 87a |
Intrepid 2F | 0.12 | 67abcd | 93a | 100a |
Intrepid 2F | 0.25 | 53abcd | 60a | 87a |
MVP II | 0.50 | 60abcd | 73a | 80a |
Proclaim 5SG | 0.008 | 73abc | 93a | 100a |
Proclaim 5SG | 0.010 | 80abc | 100a | 100a |
Proclaim 5SG | 0.015 | 87ab | 93a | 100a |
Success 2SC | 0.019 | 27cd | 73a | 87a |
Success 2SC | 0.03 | 33bcd | 73a | 93a |
Success 2SC | 0.049 | 47abcd | 73a | 93a |
Untreated check | 13d | 13b | 13b |