Biological control potential of Dinarmus basalis (Rond.) (Hymenoptera: Pteromalidae), a larval-pupal ectoparasitoid of the pulse beetle, Callosobruchus chinensis (L.)

Abstract

The parasitic wasp, Dinarmus basalis (Rond.), was introduced at six densities to suppress residual populations of ca 600 pulse beetle, Callosobruchus chinensis (L.), breeding in red lentil debris in a 46.24 m 2 room. The release rates were 5, 10, 20, 30, 40 and 50 pairs of parasitoids. The highest density, 50 pairs, suppressed the C. chinensis population 100% in the April–May period, but in the July–August period, 30 pairs could achieve this result. More progeny per female parasitoid were produced at the lower parasitoid densities than at the higher levels in both periods. In another test, ca 500 pulse beetles per 275 g of lentils, kept separately in each of three types of bags (amemian, jute and polypropylene) were exposed in the room to 50 pairs of parasitoids. Highest percentage of suppression and parasitism occurred in amemian bags and lowest in polypropylene bags when a single release of 50 pairs of D. basalis were made during both periods.