Assessment of Available Tools for Monitoring Wheat Midge (Diptera: Cecidomyiidae)

Wheat midge, Sitodiplosis mosellana Géhin, is an invasive pest of wheat, Triticum aestivum L. (Poaceae) throughout Canada and the United States. The applicability of available monitoring tools, including sex-pheromone baited traps, yellow sticky cards, and soil core sample surveys, in the northern-most agroecosystem of its invasive range has not been assessed. In this study, the attraction of male wheat midge to two Delta traps (green and orange) baited with one of three pheromone lures (a flex lure and two red septa lures from different sources) were compared. The efficacy of three yellow sticky cards (7 × 12 cm, 14 × 18 cm, and 14 × 18 cm rolled into a cylinder) for capture of male and female midge was assessed. Larvae were extracted from wheat heads sampled at the same sites to determine relationships with earlier adult trap capture. More male adult midges were captured in pheromone-baited traps with a greater surface area and in traps baited with the Scotts flex lure than the Great Lakes IPM septa lure, which had higher and more variable pheromone release rates. The smaller yellow sticky cards captured more male and female midges than the larger yellow sticky cards, regardless of shape. The number of female midges captured on yellow sticky cards predicted the number of larvae in wheat heads. The number of male midges captured in pheromone-baited traps did not predict larval density. Relationships were found between the number of overwintering cocoons recovered in soil core samples and emerging midges the following spring.