Effect of ethanol extract of Catharanthus roseus, Ocimum sanctum and Lantana camara on fecundity and fertility of red cotton bug, Dysdercus koenigii Fabricius (heteroptera: pyrrhocoreidae)

Bioefficacy of ethanol leaf extract of Catharanthus roseus, Ocimum sanctum and Lantana camara leaves was evaluated on fecundity and fertility of the red cotton bug, Dysdercus koenigii. The Phytoconstituents of each plant were extracted individually with ethanol by ‘cold extraction method’. The seeds were soaked with the 2.5% and 1.25% extracts. The newly emerged fifth instar nymphs were fed on the treated seeds for 24 h. The oviposition behaviour, fecundity and fertility of the females emerged from the treated nymphs were assessed. Our study indicated that the Dysdercus koenigii showed marked reduction in their reproductive success in response to the plant extracts. The treated females laid lesser number of egg batches and eggs in their life span. Catharanthus leaf ethanol extract was most effective in suppression of oviposition among the plants extracts tested. The eggs laid by the mated females were fertile indicating insemination of the mated females; however, the percent hatchability of the eggs laid by the females was less. The eggs laid by the females treated with Ocimum leaf ethanol extract were least fertile. It was surmised that some of compounds present in the extracts individually or synergistically alter fecundity and fertility of Dysdercus koenigii.