Multiplication of Some Stored-Product Insects on Varieties of Wheat, Oats, and Barley1

Abstract

Multiplication of 4 species of stored-product insects on 35 varieties of cereal grain grown at Glenlea, Manitoba, was determined. Resistance or susceptibility of a cereal or variety to an insect was assumed to be in inverse relation to multiplication of that insect. Multiplication of the insects was generally greater among the varieties of oats and barley than among common and durum wheats. All insects except Cryptolestes turcicus (Gourville) multiplied on all varieties of cereals; C. turcicus did not multiply on oats and certain varieties of durum wheat and barley. The rice weevil, Sitophilus oryzae (L.), multiplied least on whole kernels of ‘Manitou’ wheat, ‘Montcalm’ barley, and ‘Dorval’ oats. S. zeamais (Motschulsky) did not increase at a different rate ( P<0.05 ) when reared on varieties of common and durum wheat. The saw-toothed grain beetle, Oryzaephilus surinamensis (L.), reproduced well on all cereals but best on crushed oats. Rates of multiplication of the insect species, however, did not differ ( P<0.05 ) among varieties of common wheat and barley. A hulled emmer wheat, Triticum dicoccum Schrank, was highly resistant to whole-grain feeding insects and the broken-grain feeder C. turcius . The degree of resistance of a variety to the stored grain insects may be related to hardness of kernels, presence and nature of the hull, and nutritional value of the cereal variety.