Department of Plant Pathology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore-641003, Tamil Nadu.
Abstracts of the papers presented at the 16th Annual Convention and International Symposium of Indian Virological Society on “Management of Vector-Borne Viruses” at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru-502324, Hyderabad, India, February 7–10, 2006.
A survey was conducted to record the occurrence of whitefly-transmitted geminiviruses (WTGs) in four districts of Tamil Nadu. Various plant and weed species infected by WTGs were collected during survey and preliminary studies were conducted, which revealed that the bitter gourd plant exhibiting the yellow mosaic symptom was new and it was devastating on bitter gourd in all the surveyed areas. A detailed study was conducted on its identity and management. The disease was confirmed to be transmitted to healthy bitter gourd plants by graft and whitefly Bemisia tabaci Genn, but not by sap. The virus was transmitted through sap only to Nicotiana benthamiana thus confirming that it is a species in geminivirus. Studies on the whitefly transmission revealed that forty-five viruliferous adult whiteflies were required to transmit the disease to the tune of hundred per cent. Cassava (Monihot esculenta) and three weed species viz., Acalypha indica L., Croton sparsiflorus Bail, and Malvastrum coromandelianum (L.) Gracke, respectively, were found to be the hosts of this virus. Serodiagnosis of the virus revealed that ACMV polyclonal antibody and ICMV monoclonal antibody trapped the particles from the extracts of yellow mosaic infected bitter gourd plants and other WTGs infected plants. Polymerase chain reaction technique using Deng's degenerate primer for geminivirus and ICMV DNA-A specific primer resulted in an amplicon size of 560 bp. From this study it has been concluded that ICMV in bittergourd is reported for the first time from Tamil Nadu and this virus is whitefly-transmitted geminivirus.
