Screening of maize genotypes against stem borers and their management with newer insecticides

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dc.contributor.advisorMADHUMATHI, T
dc.contributor.authorJYOTHI, P
dc.date.accessioned2018-05-07T08:54:45Z
dc.date.available2018-05-07T08:54:45Z
dc.date.issued2016
dc.descriptionD5264en_US
dc.description.abstractStudies on the field screening (rabi 2013-14 and rabi 2014-15) of twenty two maize genotypes including two checks to identify resistant genotypes against the maize stem borers were conducted. These genotypes were further tested for morphological and bio chemical plant characters for resistance against stem borers. Survey in Guntur district for stem borers and its natural enemies in rice fallow maize were conducted. Studies were also conducted to study the influence of different nitrogen levels on stem borers and evaluation of certain newer insecticides against stem borers at Agricultural College farm, Bapatla, Guntur, Andhra Pradesh, India. Based on the intensity of damage score against stem borers, six genotypes, viz., ST X BM 254-1, Dhk 12 X 5321, ST X BM 32, ST X 5422, ST X BM 258-1 and ST X BM 59-3 were resistant. The genotypes P3596, Dhk 12 X CM 1504, DHM 117, Dhk 12 X CM 142, ST X 5311, ST X 5416, ST X BM 254-3 and Dhk 12 X CM 151 were moderately resistant. The genotypes ST X BM 59-1and P3396 are intermediate resistant. Among the resistant maize genotypes, STX BM 254-1, Dhk 12X 5321, STX BM 32 and STX BM 258-1 exhibited high level of resistance against the damage parameters viz., dead hearts, leaf damage, plant infestation, larval population, tassel damage, cob borers, exit holes and tunnel length. Among the various plant morphological characters viz., plant height, number of nodes, trichome density, stem diameter, cob height, seed weight and dry matter showed significant and negative correlation with the no. of larvae and plant infestation, where as internodal length has showed significant positive correlation with no. of larvae and plant infestation. The bio-chemical plant characters viz., nitrogen, carbohydrates and proteins showed significant and positive correlation, while phenols showed significant negative correlation with damage parameters caused by stem borers. Surveys conducted in rice fallow maize during rabi 2013-14 and rabi 2014-15 in Guntur district revealed that only spiders (Agriope spp, Phidippus sp, Oxyopes spp, Xyticus spp, etc) and coccinellids (Chilonemus sexmaculata, C. septumpunctata and Cycloneda spp) were recorded among the predators and the highest per cent of dead hearts were recorded at Kakumanu and Vemuru mandals. The damage parameters like plant infestation, leaf damage, stem borer larval population, dead hearts, exit holes and tunnel length were found to be highest with high nitrogen levels (N6 (210 kg/ha) followed by N5 (180 kg/ha), N4 (150 kg/ha), N3 (120 kg/ha), N2 (90 kg/ha), NI (60 kg/ha) and N0). Among the insecticides tested, carbofuran, flubendiamide and indoxacarb were the most effective insecticides against maize stem borers with the highest per cent reduction of population over untreated control. The grain yield was highest in flubendiamide treated plots which was on par with carbofuran and indoxacarb. Among the insecticides tested flubendiamide, spinosad, emamectin benzoate and indoxacarb were safest and recorded the highest number of natural enemies viz., spiders and ladybird beetles. The incremental cost benefit ratio was found to be highest with carbofuran followed by flubendiamide.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810044755
dc.keywordsScreening of maize genotypes against stem borers and their management with newer insecticidesen_US
dc.language.isoen_USen_US
dc.pages281en_US
dc.publisherAcharya N.G. Ranga Agricultural Universityen_US
dc.research.problemScreening of maize genotypes against stem borers and their management with newer insecticidesen_US
dc.subEntomologyen_US
dc.subjectnullen_US
dc.themeScreening of maize genotypes against stem borers and their management with newer insecticidesen_US
dc.these.typePh.Den_US
dc.titleScreening of maize genotypes against stem borers and their management with newer insecticidesen_US
dc.typeThesisen_US
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