Performance responses of navel orangeworm, Amyelois transitella (Walker), to damage treatments on eleven almond varieties

Performance of the navel orangeworm, Amyelois transitella (Walker), was evaluated on eleven California varieties of almond, Prunus dulcis L. Navel orangeworm (NOW) responses to three nut damage treatment levels (intact nutmeat, damaged pedicel, and unshelled) were evaluated on the following almond varieties: Aldrich, Carmel, Johlyn, Livingston, Monterey, Nonpareil, Padre, Price, Plateau, Sonora, and Wood Colony. Performance was measured by adult moth weight and probability of survivorship. Almond variety, nut damage status, and interactions between variety and nut damage had significant impacts on both moth weight and probability of survivorship. Nonpareil, the most important commercial variety was used as a baseline for comparisons of performance, analyzed at each treatment level due to the significant interaction between survivorship and moth weight. This is the first experimental evidence demonstrating that NOW performance is impacted by almond variety and nut damage. These results have implications for both experimental assessments of navel orangeworm performance and its management in almond orchards.