Reduction in Fertility by Nerium indicum Leaves Extract in Adults of Red Flour Beetle, Tribofium castaneum （Coleoptera： Tenebrionidae） Compared with Coopex （Bioallethrin： Permethrin）

Recent trend for the control of insect pests has been towards the use of substances of plant origin. Reductionin fertility was determined in red flour beetle, Tribolium castaneum (Herbst.) by Nerium indicum Millleaves extract compared with coopex applied by contact method under laboratory condition. When adults were placed on filter paper treated with 7.86, 9.43, 11.01, 12.58 and 14.15 µL/cm 2 doses of N. indicum leaves extract, fertility was 154 ± 15.2, 139 ± 15.0, 126 ± 6.0, 89 ± 12.2 and 72 ± 13.6 larvae/pair, compared with untreated and controls fertility (233 ± 16.0 and 190 ± 15.1 larvae/pair, respectively). However, the reduction in fertility was 33.2 ± 6.4%, 39.7 ± 3.7%, 45.7 ± 2.9%, 58.0 ± 4.4% and 66.3 ± 5.1% by the same doses of N. indicum extract. Moreover, adults treated with the same doses of coopex with the same method, fertility was 160 ± 14.6, 154 ± 9.3, 140 ± 11.2, 113 ± 7.5 and 71 ± 4.8 larvae/pair, compared with controls fertility (211 ± 8.5 larvae/pair), respectively. Furthermore, reduction in fertility was 24.3 ± 5.2%, 30.2 ± 6.4%, 37.2 ± 8.0%, 51.3 ± 1.4% and 58.8 ± 4.7% by the same doses of coopex. Minimum fertility was found in August and maximum was in July in both, N. indicum extract and coopex treated batches. The trend of reduction in fertility was the same in both N. indicum leaves extract and coopex, i.e., it was increased gradually from lower to higher doses. Nerium indicum leaves extract reduced fertility significantly compared with coopex.