Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 19, 2010
Publication Date: July 6, 2010
Citation: Lacey, L.A., Shapiro Ilan, D.I., Glenn, G.M. 2010. Post-Application of Anti-Desiccant Agents Improves Efficacy of Entomopathogenic Nematodes in Formulated Host Cadavers or Aqueous Suspension Against Diapausing Codling Moth Larvae (Lepidoptera: Tortricidae). Biocontrol Science and Technology. Vol 20:909-921. Interpretive Summary: Codling moth is the most serious pest of apple and other pome fruit worldwide. In temperate climate, after harvest, overwintering larvae make up 100% of the population. Significant reduction of overwintering codling moth larvae would provide substantial protection to apples and pears early in the following growing season. Researchers at the USDA-ARS, Yakima Agricultural Research Laboratory, Wapato, WA, S.E. Fruit and Tree Nut Research Laboratory, Byron, GA and Bioproduct Chemistry and Engineering, WRRC, Albany, CA developed and evaluated formulations of insect-specific nematodes for control of cocooned codling moth larvae in apple and pear orchards. It was found that infective stages of two species of nematodes were highly effective at controlling cocooned larvae in orchards if moisture was maintained for several hours after application of the nematodes. Formulation of the nematodes in anti-desiccant adjuvants to retard drying of the nematodes significantly improved their activity for killing overwintering codling moth. These findings indicate that improved formulation of insect-specific nematodes could provide a non-chemical means of control of codling moth when all or most of the population is in the overwintering (cocooned) phase.
Technical Abstract: Codling moth (CM), Cydia pomonella L. is the most serious pest of apple and other pome fruit worldwide. In temperate climate, diapausing cocooned larvae make up 100% of the population. Control of this stage would reduce or eliminate damage by first generation CM in late spring and early summer. Entomopathogenic nematodes (EPNs) are good candidates for their control in the cryptic habitats used for larval overwintering. The two predominant limiting factors for EPNs are adequate moisture and temperatures below 15°C. Formulation that maintains moisture and enables survival of infective juveniles (IJs) of EPNs until they can infect overwintering larvae would significantly improve their utility for protection of apple, pear and walnut. In laboratory studies in moist mulch, formulated Galleria mellonella cadavers infected with Steinernema carpocapsae, S. feltiae or Heterorhabditis bacteriophora produced 42, 88, and 24% mortality, respectively in CM larvae. Mulched field plots treated with the formulated cadavers infected with S. carpocapsae or S. feltiae IJs with an application of wood flour foam resulted in 56 and 86% mortality, respectively. Mortalities of CM larvae in plots without foam were markedly lower at 15 and 18%, respectively. Comparative tests of aqueous suspensions of S. carpocapsae IJs applied to cardboard bands on apple tree trunks followed by water, fire retardant gel or foam resulted in 11, 35, and 85% respective mortalities. Identical tests with S. feltiae resulted in 20, 19, and 97% respective mortalities.