Interaction between natural and synthetic fruit odor influences response of apple maggot flies to visual traps

Abstract

AbstractIn order to improve perimeter trapping for apple maggot fly behavioral control, we designed a set of experiments which aimed to reach a better understanding of the nature of the interaction between the natural host odor released by susceptible and low‐susceptibility apple cultivars, and an artificial host odor currently employed as a lure along with visual traps for apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), perimeter trapping programs. The response of apple maggot flies to lured and unlured visual traps deployed in different rectangular arrays of susceptible and low‐susceptibility apple cultivars (two central trees of a particular cultivar surrounded by four perimeter trees of the same or a different cultivar) was evaluated over 2 years under field conditions. In uniform blocks of susceptible (Tidemann Red, Jersey Mac) or low‐susceptibility (Marshall McIntosh) cultivars, lured traps recovered a significantly greater proportion of the total capture than unlured traps, irrespective of lure position (center or perimeter trees). Unlured traps on central susceptible apple cultivars (Red Astrachan, Gala, Fuji) recovered a significantly greater proportion of the total capture than unlured traps on surrounding low‐susceptibility cultivars (Marshall McIntosh, Paula Red, Red Delicious, and Golden Delicious). Placing the lures near traps on low‐susceptibility cultivar trees surrounding unlured traps on central susceptible cultivar trees reduced apple maggot fly visits to traps on central trees, but the latter still recovered a similar proportion of the total capture as lured traps on perimeter trees. By contrast, placing the lures near traps on central susceptible cultivar trees surrounded by unlured traps on low‐susceptibility cultivar trees allowed lured central traps to receive a significantly greater proportion of the total capture than unlured perimeter traps. We conclude that the synthetic and natural host odor of susceptible cultivars interact additively in attracting apple maggot flies to visual traps, and that, when given the choice, traps and lures should be deployed on preferred rather than on less preferred cultivar trees. Implications for trap deployment strategies for tephritid monitoring and control are discussed in the light of our findings.