Varietal preference and eco-friendly management of major insect-pests of maize during storage
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Date
2020-06
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CCSHAU, Hisar
Abstract
Studies on Varietal preference and eco-friendly management of major insect-pests of maize during storage
were carried out during 2017-19, in the Department of Entomology CCS HAU, Hisar. The study was based on
evaluation of 15 maize genotypes against S. oryzae, R. dominica and T. granarium, evaluation of biochemical
losses in various maize genotypes due to infestation by these insect-pests and to test efficacy of different seed
protectants against major insect-pests of stored maize. The experimental results revealed that maximum pooled
mean susceptibility index of 5.0, 4.7 and 4.7 was recorded for S. oryzae, R. dominica and T. granarium,
respectively, in sweet corn therefore, it was categorized as moderately resistant genotype while minimum pooled
mean susceptibility index of 1.6, 2.1 and 1.6 was recorded for HKi 161 so, it was categorized as resistant genotype.
HKi 161 was found to be resistant to S. oryzae with minimum (8.67) pooled mean percent grain damage while
HQPM 1 was found resistant for R. dominica and T. granarium with minimum pooled mean percent grain damage
of 13.88 and 11.00, respectively. The minimum pooled mean percent weight loss of 8.26 and 7.58 was recorded in
HQPM 1 against S. oryzae and R. dominica respectively while for T. granarium minimum (12.85) pooled mean
percent weight loss was recorded in HKi 161. The biochemical parameters viz phenol, total soluble sugar, ash,
moisture and protein were analysed in uninfested and infested seeds of various maize genotypes. The phenol, ash
and protein showed reduction as the infestation intervals increases while moisture and total soluble sugar showed
increase as the infestation intervals increases. In samples infested with S. oryzae, R. dominica and T. granarium,
susceptibility index showed negative correlation with phenol (-0.79, -0.72, -0.71), positive correlation with TSS
(0.84, 0.81, 0.83), moisture content (0.87,0.63,0.69) and protein content (0.29,0.65,0.24), respectively while
percent grain damage showed negative correlation with phenol (-0.86, -0.74, -0.57), positive correlation with TSS
(0.71, 0.71, 0.74) , moisture (0.84,0.66,0.56) and positive correlation with protein (0.30, 0.31 , 0.21), respectively.
After infestation, percent weight loss showed negative correlation with phenol (-0.74, -0.69,- 0.65) while positive
with TSS ( 0.64, 0.68, 0.80), moisture (0.74, 0.44, 0.69) and protein (0..31, 0.38, 0.13). Bioefficacy of various seed
protectants against S. oryzae, R. dominica and T. granarium revealed that neem oil @ 15ml/kg seed was
significantly superior over rest of the treatments with highest pooled mean percent adult mortality of 94.76, 91.90
and 92.83, respectively. It was most ecofriendly treatment with minimum pooled mean S. oryzae adult population
growth of 12.54 and pooled mean T. granarium larval population growth of 77.57 whereas for R. dominica,
cannola oil @ 20 ml/kg seed found most effective with minimum (12.44) pooled mean adult population growth.
The neem oil, eucalyptus oil and cannola oil showed zero per cent pooled mean grain damage for S. oryzae, R.
dominicaand T. granarium. The repellency activity revealed that neem oil showed maximum (80 %, 80 % and
86.67 %) mean repellence against S. oryzae, R. dominica and T. granarium, respectively which was followed by
eucalyptus oil. The maximum (96%) germination was recorded for eucalyptus leaves followed by fly ash & control
(92% each), turmeric powder (90%), neem oil and silica gel (86% each), eucalyptus oil & paddy husk (84% each),
paddy husk ash (80%) and canola oil (74%). The boric acid showed adverse effect on germination of maize seeds.