Development/​inhibiting activity of some tropical plants against Sitophilus
zeamais Motschulsky (Coleoptera: Curculionidae).

Haque MA, Nakakita H, Ikenaga H, Sota N.

National Food Research Institute, Tsukuba, Ibaraki, Japan

Thirteen tropical plants were evaluated for development/​inhibiting activity
against Sitophilus zeamais. The bioassays were carried out by incorporating
seeds or leaves at various dose levels into an artificial diet for the test
insect. It was found that seeds of Basella alba and leaves of Operculina
turpethum and Calotropis gigantea were potent in delaying development and in
reducing adult emergence, and hence the capacity for population increase. At
0.5% concentration, adult emergence in tests with B. alba, O. turpethum and C.
gigantea was reduced by 62, 95 and 70%, respectively. In B. alba and C.
gigantea, the development periods were 2.2 and 1.8 times those in the control
and the capacities for increase/day were only 0.0324 and 0.0328 compared with
0.1004 in the control. B. alba, O. turpethum and C. gigantea were active at
concentrations as low as 0.01, 0.05 and 0.1%. The potential of these materials
in insect pest management is discussed.

PMID: 10758266 [PubMed /​ as supplied by publisher]