Some like it stinky: Seedcorn maggot and their attraction to silage alfalfa

Volatile organic compounds (VOCs) are some of the most used environmental cues for resource-searching in insects. Whether seeking food sources, oviposition sites, or other insects, volatile cues provide information that can either attract pollinators and natural enemies or repel pests in crops. These naturally occurring VOCs are a valuable tool for growers seeking to shift from conventional to more integrative pest management strategies. Delia platura (Meigen), or seedcorn maggot is a widely distributed pest, often feeding on legumes, allium, and cereal grains. It is known that D. platura relies on olfactory cues when searching for oviposition sites. To determine how effective these cues are for fly attraction in the lab, we tested previously reported attractants (silage alfalfa, fresh alfalfa, meat meal, manure, fish meal, bone meal, soil, and a p-316 attractant) for efficacy as a potential lure for D. platura in three at-risk crop species (corn, soybean, and snap bean). We found that traps containing silage alfalfa and manure attracted more females (%) than the conventional p316-attractant. We subsequently tested the attractiveness of fermented alfalfa, manure, and their combination under field conditions, to determine how these soil amendments affect seed damage of corn and bean seeds in early spring. These results will allow us to propose management strategies to trap or control seedcorn maggot. Future work will focus on identifying the compounds in volatile cues of manure and silage alfalfa are responsible for increased oviposition and test if those volatiles can be used as traps to reduce seedcorn maggot populations.