Control of Codling Moth in California Pear Orchards Using Granulosis Virus

Elkins, R., Ingels C., Niederholzer F., VanSteenwyk B., Varela L., and Wunderlich L.
University of California Cooperative Extension, USA

Control of Codling Moth in California Pear Orchards Using Granulosis Virus Codling moth (Cydia (Laspeyresia) pomonella) (CM) mating disruption (MD) has become the standard practice in the California pear industry. Organic growers (463 acres in 3 counties) are currently permitted to utilize only hand-applied dispensers, supplemented by horticultural oil, Bacillus thurengiensis (BT), and more recently, kaolinic clay (e.g. Surround®, Englehard, Iselin, NJ) and an organic formulation of spinosad (Entrust®, Dow AgroSciences, Indianapolis, IN) .

In 2001, 2003 and 2005, MD was combined with several formulations of codling moth granulosis virus (CMGV) in seven replicated and 10 demonstration (non-replicated) trials in six Northern California counties. Materials included Virosoft® (2001, Biotepp, Quebec, Canada), Carpovirusine® (2003, Sumitomo Corp, New York, NY), and Cyd-X® (2003, 2005, Certis USA, Columbia, MD). (Data from 2001 trials using Virosoft® are omitted as the product was found to be non-active at the time of investigation). Trials were either hand gun (1) or grower applied (16) and all conducted in orchards with a history of CM damage. Seven orchards were certified organic and 10 were conventional. Only data from organic orchards are shown.

CMGV was applied 6-11 times, depending on location and CM population. CMGV was compared to MD plus the alternative organically-acceptable materials listed above. In most cases, MD alone was the control treatment; completely untreated controls were included in two trials.

Two years combined data (2 to 8 replicates, depending on treatment) showed MD plus CMGV (7 replicates) provided an average of 58% more control than MD plus alternative materials (9 replicates), 70% more control than MD alone (6 replicates) and 95% more control than completely untreated controls (2 replicates). The trend was similar in conventional orchards. It is anticipated that a CMGV product will be registered in California in 2006, providing a valuable new tool in organic, as well as conventional, pear orchards.

 

Presentation given at the Symposium