Abundance of Bagrada Bug, Bagrada hilaris, on Weeds and Preference for Selected Weeds and Crops in the Brassicaceae in Saltillo, Mexico

The invasive Bagrada bug, Bagrada hilaris, has expanded its range into northern Mexico where it is already causing economic losses on cultivated Brassicas. In this work we estimated populations of Bagrada bug in wild host plants in the fall-winter of 2014-15 (fall is the local growing season for cultivated Brassicas) at Saltillo, state of Coahuila, Mexico, and observed the bug preference for three plant hosts in the Brassicaceae: the weeds, arugula (Eruca sativa) and London rocket, Sisymbrium irio, and cultivated broccoli, Brassica oleracea Italica, in the greenhouse.  On 6-19 October, there were field populations of up to 68 bugs/Eruca plant, and 161 bugs/Sisymbrium plant. In choice experiments on potted plants in the greenhouse, the bagrada bugs appeared to have a preference for weed hosts (Eruca and Sisymbrium) over half-grown broccoli plants. Extensive feeding damage was observed first on weeds and posteriorly on broccoli. These results indicate  the importance of weed hosts on integrated pest management of Bagrada bug at Saltillo.