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Subject: Agricultural Entomology × End date: 2009 × Start date: 2009 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Studies on host plant resistance of sugarcane against sugarcane wooly aphid, Ceratovacuna lanigera (Zehnter) (homoptera : Aphididae)
    (UAS Dharwad, 2009) Fernando Eureka; K.Basavana Goud
    Studies 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.
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    ThesisItemOpen Access
    Market information system and its application for agricultural commodities in Karnataka state - a case of onion
    (UAS Dharwad, 2009) C.P.Amrutha; L.B.Hugar
    Studies 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.
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    ThesisItemOpen Access
    Exploitation micromus igorotus Banks and micromus timidus Hagen (Hemerobliidae: Neuroptera) in the management of aphids in cotton and tobacco
    (UAS Dharwad, 2009) S.S.Navi; S.Lingappa
    Micromus timidus accepted nine aphid species and a psyllid as host. Leaves, open bolls and cotton thread served as oviposition substrates. Full grown larva pupated in double layered cocoon in counseled places. Aphis gossypii and Melanaphis sacchari found to be most suitable hosts as growth, development reproductive traits and feeding potential were in favour. Egg to adult and egg to egg duration was shortest on A. craccivora followed by M. sacchari. Both larva and adult of M. timidus consumed higher number of A. gossypii and M. sacchari as most palatable food sources. Morphometry of mouth and body parts were also recorded. Rearing of Micromus igorotus on A. gossypii and C. lanigera for five generations did lower fecundity slightly but not other traits. Reduction in survivability of egg, larva and adult was evident. Micromus igorotus @ 1,000 adults/ha outperformed in reducing cotton aphid population. Five pairs of M. timidus adults/plant reduced the cotton aphid population. Five pairs of M. timidus adults/plant reduced the cotton aphid population effectively with higher predatory recovery. On tobacco, 20,000 to 25,000 M. igorotus adults/ha reduced aphid population and increased yield by 46.6 and 56.8 per cent. Release of five pairs of M. timidus adults/plant was also effective. Emamectin benzoate was highly toxic to all stages of M. igorotus and M. timidus and thiodicarb was least toxic to eggs and larva. Profenophos at recommended field concentration persisted at greater level to inflect above 90 per cent mortality to grubs up to 7 days and retained toxicity for 30 days. The order of persistent toxicity was profenophos>thiomethoxam >methomyl>imidacloprid>novaluron>thiodicarb>emamectinbenzoate>spinosad> indoxacarb. Micromus igorotus eggs were devoured by C. carnea grubs, C. sexmaculata grubs and adults and syrphid maggots under free choice in the presence of aphid. While, M. igorotus did not feed on any stage of these predators.