Abstract: Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)
is a primary pest of cowpea and other legumes worldwide, both in fields
and in stored seeds. Castor oil at 5, 6, 7, 8 and 9 mL kg-1
and Hazelnut at 2.8, 4.4, 6, 7.6 and 9.2 mL kg-1 were tested
against C. maculatus in cowpea. All bioassays were conducted at
27±1°C and 65±5% r.h and mortality was counted after
24, 48 and 72 h of exposure. After the 72 h mortality count, all adults
were removed and the vials were left at the same conditions for further
35 days to assess progeny production. The increase of dose and exposure
interval increased mortality. After 72 h of exposure, mortality received
to 80.83% on Hazelnut oil at high rate (9.2 mL kg-1). Mortality
in the case of Castor oil was higher than Hazelnut and received to 86.66%
at 9 mL kg-1. The lowest LC50 value on 72 h was
observed in the Hazelnut (6.57 mL kg-1). In contrast, the lowest
LC95 value on 72 h was observed in the Castor (l0.94 mL kg-1).
Complete suppression in progeny production was achieved on cowpea treated
with Castor oil at 9 mL kg-1 but in the all case, the percentage
of reduced progeny received up to 90%. In conclusion, treatment of grain
with vegetable oil could have important practical implications for parts
of the world where pesticides are expensive or in short supply.
N. Haghtalab, N. Shayesteh and S. Aramideh, 2009. Insecticidal Efficacy of Castor and Hazelnut Oils in Stored Cowpea Against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). Journal of Biological Sciences, 9: 175-179.