Optimizing the use of the codling moth granulovirus: Final Report L. Lacey S. Arthurs R. Fritts R. Behle A. Knight

OBJECTIVES: 1.Determine the lowest dosage of CpGV that will provide effective control of codling moth larvae. 2.Determine optimal intervals for spray application. 3.Continue to assess the shelf life of commercial formulations at various temperatures. 4.Investigate the potential of several adjuvants for protecting CpGV from solar degradation.

Significant findings: ● Season-long treatments of CpGV (Cyd-X) at 3 rates (1, 3 and 6 oz acre) and 3 application intervals (7, 10 and 14 days) resulted in significantly fewer deep entries and surviving larvae but did not reduce the proportion of fruit damaged by codling moth. ● There was a significant trend of fewer deep entries and higher larval mortality rates with increasing rate of CpGV and shorter application interval. ● In replicated ½ acre plots, CpGV provided > 90% larval mortality at 1, 2 and 3 oz/acre, but was not as effective as Guthion in protecting fruit. ● Bioassay procedures to screen adjuvants providing possible UV protection of CpGV formulations were developed.

Significant findings continued: The efficacy of 3 commercial CpGV formulations were significantly reduced (52-77%) by exposure to UV light (9.36 × 10 6 joules/m 2 ) in a solar simulator. Although lignin encapsulation provided significant protection of CpGV exposed to simulated sunlight in laboratory studies, under field conditions it did not. The Cyd-X and Virosoft formulations of CpGV maintained larvicidal activity after storage at 2 and 25˚C for over 132 weeks, but activity was sharply reduced after storage at 35º for 16 and 40 weeks, respectively.

Applying CpGV in the orchard Experimental orchard Trees treated individually in a randomized plot design Commercial orchard Blocks sprayed using operational equipment

Field evaluations of CpGV Experimentally assess efficacy of weekly applications of Cyd-X at 1, 2, 3 oz/ac Experimentally assess efficacy of weekly applications of Cyd-X at 1, 2, 3 oz/ac Determine optimal spray interval and dosage of Cyd-X applied every 7, 10 or 14 days at 1, 3, or 6 oz/ac Determine optimal spray interval and dosage of Cyd-X applied every 7, 10 or 14 days at 1, 3, or 6 oz/ac % and degree of fruit damage, larval mortality, sampling overwintering larvae % and degree of fruit damage, larval mortality, sampling overwintering larvae

Virus application rate (oz/acre) Fruit damage, deep entries and CM mortality following different treatments of Cyd-X in individual tree plots.

Grower applications Assessment of: Fruit damage Fruit damage larval mortality larval mortality adult populations adult populations overwintering larvae overwintering larvae

Fruit damage, CM mortality and interception trap catches following different treatments of Cyd-X in ½ acre blocks in a 21 acre commercial orchard (data for 1st generation).

CpGV and MD is effective Year#Application s/season % CM fruit injury/1000 fruit Moths/pheromon e trap 1 st gen.2 nd gen.1 st flight 2 nd flight *0.84* CpGV (Cyd-X) applied at 2 or 3 fl.oz/A and 100 gal./ A, * assuming 300 fruit/tree Fruit injury and codling moth populations in 3A organic Golden Delicious treated with CpGV and MD (Parker Heights, WA)

Laboratory studies Quantitative bioassays Quantitative bioassays Shelf life at 36, 77, and 95˚F Shelf life at 36, 77, and 95˚F UV sensitivity UV sensitivity

Weeks in storage after which less than 95% mortality of codling moth larvae occurs (100,000 fold dilution) 36˚F - 2˚C77˚F - 25˚C95˚F - 35˚C Carpovirusine Virosoft Cyd-X end point not yet determined

Solar simulator and half apple system used to bioassay CpGV formulations Apples were sprayed with CpGV suspensions in a DeVries spray cabinet Evaluation of formulation components as ultraviolet light protectants

Mean CM mortality on apples treated with standard rate of CpGV (1000-fold dilution) and exposed to 9.36 × 10 6 joules/m2 simulated sunlight plus controls. VirosoftCarpovirusineCyd-X UV No UV % red

Evaluation of spray-dried lignin-based formulations as ultraviolet light protectants

Percentage neonate mortality on irradiated fruit with three rates of virus FormulationHigh dose (3 × OB/L) Med. dose (3 × 10 9 OB/L) Low dose (3 × 10 8 OB/L) Untreated21.4c21.4b21.4 Cyd-X55.7b44.5a37.8 Virus/Lignin95.4a41.7a37.3 Data show average for five replicate tests (n = 25) Letters show Fisher’s LSD at P < 0.05

Evaluation of spray-dried lignin-based formulations as ultraviolet light protectants FormulationFirst generation 1 Second generation 2 % fruit damage % mortality % fruit damage % mortality Untreated b c Blank Lignin b c Cyd-X a ab Virus/Lignin a a Cyd-X (½ rate) ab Virus/Lignin (½ rate) b 1 Four applications at 6.57 × granules/ha 2 Three applications, ½ trees sprayed at a reduced rate (2.2 × granules/ha) Field tests (Golden Delicious), 14 d spray interval, n=10 trees

CpGV Technology Transfer: Presentations Presentations to grower groups Presentations to grower groups –WTFRC –Tilth, Oregon –Organic Grower meetings –WOPDMC Technical Presentations Technical Presentations –Society for Invertebrate Pathology –WC43 –Regional Project on Microbial Control –Entomological Society of America

CpGV Technology Transfer: Publications Trade magazines Trade magazines –Grower –Good Fruit Grower – May 2005 –Local Ag. Periodicals 2005 –Tilth Producers Quarterly 2005 Journals Journals –J. Econ. Ent –J. Invert. Pathology 2005 –Biol. Control 2004 –J. Ent. Soc. B. C –J. Ent. Sci –WOPDMC,

Conclusions and future work Good population control but there is room for improvement Good population control but there is room for improvement Feeding stimulants Feeding stimulants Pear ester Pear ester Lignin formulations Lignin formulations Resistance Resistance –CpGV could provide tool for managing CM resistant to conventional insecticides –Evidence for CM tolerance to CpGV