Survival of Immature Stages of the Codling Moth (Lepidoptera: Tortricidae) on Seeded and Seedless Apple Fruit1

Abstract

Significant differences in infestation and survival of Cydia pomonella (L.) were found between seeded and seedless apple fruit. A smaller number of entry and exit holes and emerged adults were found on seedless fruit that developed naturally in the greenhouse, suggesting a lower suitability for this type of fruit. There were no differences in the ratio of the number of adults (or exit holes) as a percentage of larval entries. These data suggest that differences in suitability between the fruit types may be due to morphological or chemical factors associated with the fruit type. Application of a mixture of growth regulators (Promalin [N-(phenylmethyl)-1H purine 6-amine + Gibberellins A4A7] and daminozide [(SADH, DMSA, Alar-85, B-NINE, aminozide) butanedioic acid mono (2,2-dimethyl hydrazide)]) 17 days after full bloom resulted in partial seedlessnessin cv. Turley but had no effect on cv. Winesap. More infestation of the seeded fruit of ‘Turley’ was evident, with the differences in the mean numbers of stings, pupae, and adults being significantly greater on seeded than on seedless fruit harvested 41 days after blooming. Our data indicate that seeded fruit may be more important as a food source for first than second brood larvae. The effect of hormone mixtures apparently is cultivar-dependent. Natural or artificial seedlessness in apple fruit may be useful in reducing codling moth damage in commercial production, provided the fruit size can be maintained.