Oviposition preference of pink bollworm, Pectinophora gossypiella on cotton

The effect of four cultivated species of cotton on the oviposition behaviour and/or preference of pink bollworm, Pectinophora gossypiella was studied under laboratory conditions. Blends of volatile organic compounds from squares of all four species of cotton (Gossypium arboreum, G. herbaceum, G. hirsutum, G. barbadense) were identified using gas chromatography-mass spectroscopy (GC-MS). Differences were observed across the species with respect to the relative proportion of identified compounds, viz., pinene, carene, caryophyllene, humulene and γ terpinene. In order to evaluate the ovipositional preference of pink bollworm, a series of no-choice and choice experiments were conducted using square extract, artificial blend-treated muslin cloth and cotton twig as substrate for oviposition. All four species of cotton had differences in the volatile blend composition that were reflected in the mean number of eggs laid under no-choice and choice experiments. A substantially higher number of eggs was laid on cotton twig under both no-choice and choice experiments than on square extract and artificial blend treatments. In both no-choice and choice experiments G. herbaceum was found to be the least preferred for egg laying compared to the other three species.