Importations into North America of shipments of broom corn (Sorghum vugare var. technicum) have always been a source of anxiety to plant quarantine officials. It is well known that the European corn borer, Pyrausta nubilalis Hbn., was almost certainly introduced onto this continent in this commodity (22), a surmise which receives perennial support from the continued finding of this species in consignments from various parts of Europe. Broom corn is usually imported in bales weighing from 100 to 250 pounds each, (Figures 1 and 2) which contain both the brush and anything up to 12 inches of stalk necessary for the proper binding of the broom. It is interesting to note that in the country of origin, after the broom corn is harvested, it is dried and curcd and is then usually subected to the fumes of burning sulphur overnight in a closed room in order to bring about, through bleaching, a uniform yellowish colour desired in the trade. None of these treatments have any appreciable effect on the populations of living borers found in the stalks. In addition to insect pests which feed in or on broom corn as a normal host, other species may use the borings of the normal pests as sites of hibernation or pupation. Under some conditions, no doubt, stalks may be left lying in the field for some time prior to harvesting, and thus constitute a refuge for many potential pests.
European Corn Borer in North America
