SEASONAL OCCURRENCE OF SUGARCANE WOOLLY APHID (Ceratovacuna lonigera Zehntner) AND ITS NATURAL ENEMY COMPLEX IN NORTHERN DISTRICTS OF TAMIL NADU

摘要

Survey and experiments conducted by Sugarcane Research Station, Melalathur during April 2004 to March 2005 on woolly aphid incidence in sugarcane revealed that this new pest has entered border areas of Vellore District from Andhra Pradesh during April 2004, then it has been spread into all the Taluks of Vellore District and to the adjoining districts viz., Tiruvannarnalai, Dharrnapuri, and Krishnagiri. Now, it has assumed a serious pest status on sugarcane in Northern districts of Tamil Nadu. The incidence of woolly aphid was sporadic in nature and found in small isolated patches of 5-40 m~2 area. At severe stage of incidence, lot of woolly matter on soil and few winged adults migrated to the lower leaf surface in association with lot of sooty mold development on the upper surface of the lower leaves. Quantitative and qualitative parameters reductions were observed in affected cane. The natural enemies like Cheilomenes sexmaculata, scymnus, Brumoides suturalis Dipha aphidivora (a lepidopteran larva) were observed. The lepidopteran larvae found feeding in the galleries along the aphid colonies. Brown lacewing Micromus igotorus are also found feeding on aphid colonies. The high sugar varieties were found to be highly susceptible than the medium sugar varieties. Among the various insecticides tried, acephate, carbosulfan, chlorpyriphos, monocfotophos and endosulfan showed their higher efficiency within 12 hrs of application under detrashed condition. But acephate, carbosulfan brought cent per cent mortality within 24 hrs of application, whereas chlorpyriphos, endosulfan and monocrotophos have brought cent percent mortality after 36 hrs. The effectiveness of insecticides remains for shorter period only.