Evaluation of organic control tactics for apple maggot
CALS Impact Statement
Three treatments for controlling apple maggot in organic orchards were compared: (1) Curveball? spheres. (2) Entrust and (3) Gf-120 Naturalyte Fruit Fly bait. The Curveball? spheres are not approved for use in organic orchards, but the other two treatments are organically certified. Entrust was the only treatment that significantly reduced apple maggot damage at harvest below that in the check treatments. Even though the overall apple maggot damage in the Curveball? plots was not significantly lower than that in the check plots, twice as many flies were captured (505) during the season in these treatments compared to the checks (242). Therefore it appears that the Curveballs? were capable of killing large numbers of flies attracted to the plots, but their effectiveness could not compensate for the higher populations of flies that were attracted into their localized area throughout the season by the network of volatile lures. In the future, to enhance the effectiveness of this Curveball? system for controlling a localized, indigenous population of flies, it would be desirable to utilize a system that would not attract flies from long distances throughout the orchard, but would only attract flies within a single tree canopy to encounter the toxicant on the traps. Additional work will be done to attempt to increase the effectiveness of these three control tactics in the future.
The apple maggot, which is a native insect species in the Northeastern United States, has long been one of the most difficult pests to control in this apple production region because there is no tolerance for infestation of apples by larvae. In conventional orchards, various types of insecticides can provide adequate control, but currently there are very few tactics approved for use in organic apple orchards. Therefore, if better control tactics for this pest could be developed for use in organic apple production systems, it is possible that more growers throughout the Northeastern apple production areas would become interested in producing organic apples that could be marketed at a premium price. This would increase the ability of consumers within the region to enjoy locally produced organic apples instead of purchasing fruit grown in the western United States.
Three treatments were compared during this study in 2006: (1) Curveball? spheres. (2) Entrust and (3) Gf-120 Naturalyte Fruit Fly bait. Entrust was the only treatment that significantly reduced apple maggot damage below that in the check plots. Fruit damage in the Curveball plots was similar to that in the check plots, but twice as many flies were captured (505) in these treatments compared to the checks (242). Apparently, the toxicity of Curveballs? could not compensate for the higher populations of flies lured to plots by the network of volatile lures. To enhance the effectiveness of this Curveball? system for controlling localized populations of flies, a future system will be developed to only attract flies within a single tree canopy to encounter the toxicant on the traps. A complete seasonal program of Entrust and GF-120 will be tested at weekly intervals during the next season. Also, additional studies will be done to check coverage patterns of GF 120 droplets within plots by the Olive Fruit Fly Sprayer to determine if overall distribution of droplets within the canopy of treated trees was adequate. Finally, different canopy densities of unbaited Curveball? spheres, and Curveballs? baited with more localized types of lures (protein hydrolysate and/or ammonia) will be compared to determine if these more localized systems can provide better control of indigenous populations of apple maggots in individual trees.
The severity of the insect pest complex in the Northeastern United States is one of the major constraints to organic apple production within this region. Although improved tactics have been developed to facilitate the control of some key pests in organic apple orchards such as internal worms, there are currently very few organically approved methods for managing the apple maggot. The initial research conducted in this project has identified tactics that appear to be very promising for use in organic orchards, and if the effectiveness of these methods can be further improved, it would increase the opportunities for Northeastern apple growers to produce more organic apples. This increased production within the Northeastern US would provide growers in the region an opportunity to sell organic apples at premium prices and allow consumers to purchase locally grown fruit rather than purchasing organic apples produced in the Western US, where there are fewer indigenous insect and disease pests.
funding source description
Pest Management Innovations LLC
Starker Wright (Applacian Fruit Research Laboratory, USDA)