Survey for the Occurrence of Various Thrips and Sunflower Necrosis Disease in Andhra Pradesh

摘要

The Sunflower necrosis disease (SND) is inflicting severe damage in major Sunflower growing areas of Andhra Pradesh (Ananthapur, Hyderabad, Kurnool and Nandyal). To know the prevalence of SND in Andhra Pradesh fortnightly survey was conducted during August 2003 to March 2004 in Narkhoda, Kavvaguda and Chevella villages of Ranga Reddy district, Andhra Pradesh. The thrips Population/head ranging from 1.0 - 36 thrips/head and the disease incidence upto 80% was recorded during the survey. Among the threevillages surveyed, Kavvaguda recorded highest average population of thrips/ head i.e. 20.2 thrips/ head during flrst fortnight of December, where as the highest average per cent SND incidence (45.6) was recorded during second fortnight of November in Chevella. The highest monthly average thrips population/head recorded during March 2004 (16.3 thirps/ head) and the highest SND per cent incidence was high during October 2003 (38%). The SND incidence was high during September, October and November and lowduring December and January. Survey revealed that five thrips species viz., Thrips palmi (Karny), Scirtothrips dorsalis (Hood), Frankliniella schultzei (Trybom), Megalurothrips usitatus (Bagnall) and Haplotbrips gowdeyi (Franklin) were colonizing on sunflower and Partheniumhysterophorus. Among five thrips species, T. palmi was dominant constituting 64 per cent of total thrips population. Laboratory studies of DAC - ELISA and local lesion assay on cowpea (cv. C — 152) conducted on SND infected samplesconfirmed the Tobacco streak virus (TSV) as a causal agent for SND.