Plant bugs (Hemiptera: Miridae) on field beans and soybeans in Manitoba, Canada: species composition and seasonal occurrence

Abstract

AbstractIn Manitoba, Canada, commercial soybeans and two types of field beans, navy and pinto, were sampled for plant bugs. At the centre and margins of 36 fields, sweep net and tap tray samples were taken weekly. In all three crops, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae) comprised >78% and Adelphocoris lineolatus (Goeze) (Hemiptera: Miridae) <10% of adult mirids. Species composition varied among years but not among crops. For Lygus Hahn, nymphs were 46% of the catch in trays and 23% in sweeps, but total Lygus catch in trays was >2% of that in sweeps. Catch/sample effort was similar at field centres and margins for both Lygus adults and nymphs. Lygus lineolaris reproduced and developed in all three crops. In field beans, Lygus adults were first collected in late vegetative and early pod set stages and late instar nymphs and adults were present from pod elongation until maturity – results consistent with immigration of first summer generation reproductive adults and development of the second generation in the crops. There was evidence of late season immigration of Lygus into all crops. There was no loss of seed quantity attributable to mirids in any of the crops; in field beans there was no evidence that mirids reduced seed quality.