Toxicity of newer insecticides against spiralling whitefly, Aleurodicus dispersus under laboratory conditions

摘要

The spiralling whitefly, Aleurodicus dispersus Russell poses threat to many agricultural and horticultural crops both in the field conditions and glasshouse. In India, it was first recorded in 1993 in Thiruvanantapuram, Kerala on tapioca (Palaniswamiet al., 1995). Later it was reported from several parts of Kerala, Tamil Nadu, Karnataka, Andhra Pradesh and Maharashtra (David and Regu, 1995; Ranjith et al., 1996; Mani et al, 2000). The whitefly might have been introduced into India from the neighbouring countries like Maldives (Muniappan, 1993) and Sri Lanka (Ranjith et al., 1996). Nymphs and adults suck the sap from the leaves causing damage to several crops particularly cassava, brinjal, chillies, mulberry, guava, banana, papaya, coconut, groundnut, etc. in peninsular India (Mani and Krishnamoorthy, 1999; Mani, 2010). Management of polyphagous invasive pests like A. dispersus becomes all the more difficult because of the multitude of host plants that grow wild in nature and support the build-up of the pests. The various tools of management are advocated to manage the economic losses caused by this pest and it is a difficult pest to kill with biocontrol agents alone (Boopathi et al, 2013b). Use of insecticides is the first line of defence. Application of chemicals to the lower surface of infested leaves thoroughly reduces the A. dispersus abundance but temporarily. Hence, the present laboratory studies were conducted to test the efficacy of ten newer insecticides against A. dispersus to providethe organized guidance for the selection of pesticides in order to develop suitable strategy for its management.