Multitrophic system: Effect of different concentration of nutrient and pre-infested brinjal (Solanum melongena) on whitefly (Bemisia tabaci) population

摘要

The effect of nutrient concentrations and pre-infestation of brinjal (Solanum melongena) plant with pest species on population of whitefly (Aleyrodidae; Hemiptera) was investigated over a cropping period. Three dosages of nutrients (fertilizer) were applied on brinjal seedlings; N1–50ppm, N2–150ppm and N3–300ppm respectively. The brinjal seedlings were pre-infested with two pests, whitefly and aphid. The control plants were non-infested with any pest. Populations of whitefly were higher following increasing levels of nutrients in non-infested plants. No significant variation on mean population densities were observed among the sampling times. In the pre-infested brinjal plants, the level of nutrients did not influence the abundance of whitefly population infesting brinjal plants. Lower whitefly populations were observed on whitefly pre-infested brinjal plants compared to aphid infested and non-infested plants. Pre-infested plants were suspected to induce productions of secondary metabolites as a chemical defence system thus lowering the number of whiteflies on them. Whitefly populations were found higher during early growth of brinjal plants due to high number of leaves and good plant growth. Considering other management technique in controlling whiteflies on brinjal such as appropriate nutrient supplement and good pest care during seedling stage was proposed.