Evaluation of multi-tactic systems for control of internal feeding worms in western New York apples CALS Impact Statement

This project is a field validation of various new tactics, such as pheromone mating disruption, trap monitoring and threshold development, fruit damage inspection, and optimum chemical application, to improve control of fruit-feeding `worms` in western New York apples.

During the last several years, western New York apple growers have noticed increasing internal fruit damage from Lepidoptera in their orchards. Numerous loads of apples have been rejected by processors because of unacceptable infestations of larvae. This escalating problem clearly poses a threat to the continued viability of this industry. New York apple growers are already anticipating future limits to the use of broad-spectrum insecticides because of recent pesticide legislation. In addition, they are faced with low commodity prices because of increased domestic and foreign competition and higher production costs. If this new pest crisis is not solved quickly, it may hasten the decline of this already beleaguered but important regional industry.

In 2007, a full-season mating disruption trial was conducted in 5-10-acre plots on three farms, to assess the efficacy of three different multi-species pheromone products against codling moth, oriental fruit moth, and lesser appleworm: Isomate CM/OFM TT ties; Checkmate CM-OFM Duel membranes; and Suterra CM/OFM Puffers. Pheromone treatments were used as a complement to the growers` normal insecticide programs. All three dispenser technologies suppressed adult catches of oriental fruit moth and lesser appleworm to near-zero levels for the entire season, but at two of the sites, some or all of the treatments allowed some breakthrough of codling moths in late June. Placement of the CM traps in the tops of the tree canopies could have been a factor in this finding. Weekly on-tree fruit inspections detected very few damaged fruits until mid-August. Total fruit damage at harvest ranged from 0-7 percent across all sites and pheromone treatments (compared with 1-8.4% in the non-disrupted grower standards). The Duel plot had lower total damage than the non-disrupted plot at all three sites, as did the Isomate plot at one site. At one site, both of these treatments had lower total damage than in the Puffer plot.

The in-season fruit inspection regimen continues to appear effective and reliable, but there remains a difficulty in convincing growers to wait for evidence of even a low level of damage in their orchards before applying a special spray against these pests. In general, considering the overall levels of pest pressure occurring in these orchards, and the economics (considering both materials and labor) of implementing these pheromone treatments, it is possible that many internal worm problems in New York orchards could be adequately addressed by adjusting pesticide spray schedules, improving coverage, or with the use of selective products for some designated sprays. In terms of risk reduction, conventional pesticide use against these species could be reduced in situations of low to moderate population pressure, where mating disruption could be relied upon to adequately mitigate potential fruit infestations. We have seen evidence of the increasing importance of codling moth as a contributor to internal fruit-feeding damage in a number of western New York orchards, which complicates the management requirements for this pest group, and any decision to use mating disruption as a supplemental tactic will need to take this additional species into account. Although these tactics represent a substantial increased cost in a crop protectant program, they may be necessary for avoiding the higher price of having even a single load rejected by the fruit buyer.

Overview