Insect Growth Regulator Impact on Fecundity and Fertility of Adult Tufted Apple Bud Moth, Platynota idaeusalis Walker

The tufted apple bud moth, Platynota idaeusalis Walker, is a major pest of apples in the eastern United States. Resistance to conventional insecticide chemistries has made this pest difficult to control. The insect growth regulators (IGRs) tebufenozide and methoxyfenozide, which are target-specific to lepidopteran pests, have been shown to have high efficacy against P. idaeusalis larvae. These compounds are known to affect adult moths in related tortricid species, but the effects of exposure on adult P. idaeusalis are unknown. This study investigated the effects of adult exposure on the fecundity and fertility of P. idaeusalis. Both tebufenozide and methoxyfenozide significantly reduced the fecundity and fertility of female P. idaeusalis adults that were exposed to dry films of formulated IGR residue. Female fecundity and fertility also were reduced when untreated or treated females mated with treated males. Contrary to other related studies, there was no difference in fecundity/fertility reduction efficacy between tebufenozide and methoxyfenozide. Thus, because tebufenozide and methoxyfenozide have reproductive activity against adults, such compounds may bring significant benefits to integrated pest management (IPM) of tree fruits.

Storage Quality of Apples following Natural and Artificial Tufted Apple Bud Moth Feeding Injury

`Golden Delicious', `Delicious', and `York Imperial' apples (Malus ×domestica Borkh.) with various amounts of tufted apple bud moth (TABM) [Platynota idaeusalis (Walker)] feeding injury were evaluated for quality at harvest and following storage in air and controlled atmosphere. In addition, apples were artificially injured during two seasons to mimic TABM feeding injury. There was little or no effect of natural TABM injury on the quality of apples in many experiments. At harvest, firmness was not influenced by natural TABM injury, soluble solids concentration (SSC) was increased in three of 11 experiments, and starch levels decreased in two of 11 experiments. These results indicate a slight advancement of maturity of injured fruit. More severely injured fruit tended to have more decay after storage than fruit with less injury. Some injury, especially first brood injury, up to ≈7 to 10 mm2 surface damage, can be tolerated without compromising storage quality of processing apples. However, severe injury (>79 mm2) can increase decay. Second brood injury, whether caused by natural feeding of TABM or through artificial means, usually caused a higher incidence of decay than first brood injury. Artificial injury imposed close to harvest led to more decay in storage than did similar injury imposed earlier.