K.Basavana GoudFernando Eureka2016-08-022016-08-022009http://krishikosh.egranth.ac.in/handle/1/70440Studies on host plant resistance of sugarcane against sugarcane woolly aphid (SWA), Ceratovacuna lanigera Zehnter were carried out during 2006-08 at Agriculture Research Station, Sankeshwar and Saidapur farm, Main Agriculture Research Station, University of Agricultural Sciences, Dharwad. Among 21 varieties screened for SWA along with standard check CoC671, genotype MS 0129 was found highly resistant to SWA by recording lowest pest grade (1.56) with low pest density (16.60 aphids/2.5 sq cm). Six different sugarcane varieties, viz., Co 91010, Co 79158, Co 2000-06, Co 2001-09, Co 99004 and CoC671, (grade 1-6 based on the SWA infestation levels) evaluated for biophysical parameters was found significant positive correlation with leaf width (3 & 6 months old crop), stomatal density (6 & 9 months old crop) and significantly negative correlation with laminar thickness (3, 6 & 9 months old crop) with SWA grades. The biology of SWA on the above six different varieties revealed that the total nymphal duration of apterous form of SWA was shortest (21.50 days) on highly susceptible variety CoC671 and longest in Co 2000-06 (27.75 days). The per cent reduction in most of the yield parameters in unprotected crop over protected crop was comparatively low in Co 2000-06 which recorded 0.42, 1.30, 6.54 and 8.33, in number of internodes, cane height, cane girth and single cane weight, respectively at Saidapur farm. The highly resistant variety Co 91010 recorded minimum per cent reduction of quality parameters in unprotected crop over protected crop, which recorded 5.71, 6.94, 0.98 and 8.44 in brix, sucrose, juice purity and CCS percentages, respectively in Saidapur farm, being resistant to SWA The larval period of Dipha aphidivora (Meyric) reared on aphids provided from highly susceptible variety CoC671 was significantly shortest (23.63 days). The total feeding potential of D. aphidivora was low in Co 91010 (4542.75 aphids) and Co 79158 (4474.75 aphids) than rest of the varieties. There was no significant difference on the biology and feeding potential of Micromus igorotus Bank on six different varieties evaluated.Thesis