RANGASWAMY, K. T.MAHESH, Y. S.2017-03-032017-03-032011-04-25Th-10188http://krishikosh.egranth.ac.in/handle/1/5810003755Croton leaf curl virus is an important whitefly transmitted geminivirus. Characteristic symptoms of croton leaf curl disease were thickening of veins, leaf enations, upward and downward curling of the leaves. Survey of botanical gardens and nurseries indicated the occurrence of disease ranging from 6.7 to 37.14 per cent. The disease incidence was lowest in KSG Farm and Nursery, Chamarajpet, Bengaluru (6.70 %) and highest at M.R.S. Hebbal (37.14 %). CrLCuV was successfully transmitted only to the species of Tobacco viz, Nicotiana tabaccum cv. Samsun, and N. benthamiana. A minimum of 25 whiteflies per plant were required for virus transmission (10 %) while 50 per plant gave 60 per cent virus transmission. Maximum transmission (50 %) of the virus was achieved with AAP and IAP of 48 hr each. 100 per cent transmission was achieved through grafting and cuttings. Partial Coat Protein (CP) gene of CrLCuV was amplified using CP specific primers, cloned and sequenced. Phylogenetic analysis of CP nucleotide (575 bp) sequences grouped CrLCuV and Ageratum yellow vein virus Pakistan isolate (AgYVV-[PAK] in same cluster. CrLCuV shared highest nucleotide similarity with ToLCNDV (Age) (95.6 %) and but shared 83.70 per cent with ToLCBV (Ban2). CrLCuV alpha satellite DNA (1371 bp) and beta satellite DNA (700 bp) sequences shared maximum nucleotide identity with Tobacco curly shoot virus isolate Y249 (TCuSV-Y249) (93.0 %) and Cotton leaf curl Multan beta satellite-[Pak:16-3:08] (100 %) respectively. B. tabaci B biotype was found more tolerant to all four insecticides viz., Imidacloprid, Acetamiprid, Triazophos and Monocrotophos tested than indigenous type. Susceptibility of indigenous and B biotype B. tabaci to selected insecticides tested varied to a greater extent with LC50 ranging from 6.651 μg a.i/ml to 665.580 μg a.i/ml and 10.162 to 1124.071 μg a.i/ml respectively.ennullThesis