Midge (Diptera: Cecidomyiidae) injury to Brassicaceae in field trials in northeastern Saskatchewan, Canada

Abstract

AbstractTo determine resistance of Brassicaceae field crops to Contarinia Róndani (Diptera: Cecidomyiidae) midge complex (Contarinia nasturtii Kieffer and Contarinia undescribed species), field trials of two different host assemblages were undertaken near Melfort, Saskatchewan, Canada in 2014 and repeated in 2015. In both years the first midge adults appeared in early July, when most plants were starting to flower, and a second generation occurred in mid-August, past the period of crop susceptibility. In a trial studying 18 lines of six brassicaceous species, the lowest probability of midge injury was found on Camelina sativa (Linnaeus) Crantz lines in both years. No differences were found in the probability of midge injury among any of the 13 Brassica Linnaeus species lines tested, including commercial glyphosate-resistant and glufosinate-resistant Brassica napus Linnaeus canola lines, Ethiopian mustard (Brassica carinata Braun), brown or oriental mustard (Brassica juncea (Linnaeus) Czernajew), or Polish canola (Brassica rapa Linnaeus) lines. Probability of midge injury on Sinapis alba Linnaeus yellow mustard lines reached levels between those on Camelina sativa lines and those on Brassica lines. A second trial examining 14 current commercial glyphosate-resistant Brassica napus canola cultivars found no differences in susceptibility to midge feeding among any cultivars tested. More plants were damaged in 2015 in both studies, and damage reached maximum levels earlier in 2015 than in 2014.