Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2007
Publication Date: 6/1/2007
Citation: Arthurs, S.P., Hilton, R., Knight, A.L., Lacey, L.A. 2007. Evaluation of the Pear Ester Kairomone as a Formulation Additive for the Granulovirus of Codling Moth, Cydia pomonella (L.) in Pome Fruits. Journal of Economic Entomology 100:702-709. Interpretive Summary: Codling moth is the most serious insect pest of apple in the Pacific Northwest of the United States. The granulovirus of the codling moth (CpGV) has recently been registered as an environmentally safe microbial pesticide and is used by orchardists in this region to selectively control codling moth larvae. Improvement in uptake of the virus would further improve its activity. In 2005 and 2006 researchers at the USDA-ARS Yakima Agricultural Research Laboratory and the Oregon State University Research and Extension Center in Central Point, OR evaluated a commercial formulation of the virus in combination with a microencapsulated pear ester formulation for improved larvicidal activity and fruit protection. Results showed that the addition of pear ester to the virus had significant, but inconsistent effect on larval mortality and fruit protection.
Technical Abstract: Orchard studies were conducted in 2005 and 2006 in apple and pear to evaluate the larval kairomone (E,Z)-2,4-decadienoate (pear ester) as a formulation additive to improve the efficacy of the granulovirus (CpGV) of the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae). The addition of a 5% a.i. microencapsulated formulation of pear ester (PE-MEC) had significant but inconsistent results in our tests. In ‘Golden Delicious’, PE-MEC (3.7 g a.i./ha) added to CpGV (2.2 - 6.6 × 1012 granules/ha) significantly reduced overall codling moth fruit injury in the second but not the first larval generation, although no reduction in the numbers of live larvae (dissected from infested fruit or collected in orchard tree bands) was observed. In 2006 apple tests, the addition of PE-MEC (4.7 g a.i./ha) to CpGV (6.6 × 1012 granules/ha) did not reduce fruit injury or increase larval mortality of first generation codling moth in mixed blocks, ‘Golden Delicious’, ‘Fuji’, ‘Gala’ and ‘Delicious’. In studies in ‘Bartlett’ pear in 2005, a low rate of PE-MEC (1.5 g a.i./ha) added to CpGV (1013 granules/ha) caused a moderate reduction in fruit injury at harvest compared with CpGV alone, but no reduction was observed in 2006 when a higher rate of PE-MEC (3.7 g a.i./ha) was tested. However, in the latter tests, the percentage of larval mortality and shallow stings in infested fruit was higher in CpGV + PE-MEC treatments over CpGV alone, which was not observed in 2005. Compared with untreated controls, the PE-MEC formulation alone also reduced fruit injury (mid-season in ‘Bartlett’) and larval survivorship inside infested fruit at harvest (2006 apple tests and both years in ‘Bartlett’).