Studies on screening of genotypes and effect of different dates of sowing on incidence of major insect pests of castor
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Date
2019
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CCSHAU
Abstract
The present investigations entitled “Studies on screening of genotypes and effect of different dates of sowing on incidence of major insect pests of castor” were conducted during 2018-19 at Chaudhary Charan Singh Haryana Agricultural University, Regional Research Station, Bawal. Twelve genotypes were screened against four major insect pests of castor- leafhopper, Empoasca flavescens; castor shoot and capsule borer, Dichicrocis punctiferalis; castor semilooper, Acanthodelta janata and tobacco caterpillar, Spodoptera litura. The genotype Maharaja 9 was found superior due to minimum incidence of all these insects as well as maximum yield. The incidence of these insects was also observed on six different dates of sowing on castor hybrid DCH 177. The crop sown on 20th May exhibited maximum incidence of D. punctiferalis and S. litura but yield was lowest among all sowing dates. Sowing done on 3rd August suffered maximum infestation of E. flavescens and A. janata. Sowing done on 4th July, 2018 was moderately damaged by insect pests and maximum yield was recorded in this sowing as well. The peak infestation level of E. flavescens was noticed during 44th SMW, whereas the maximum capsule damage by D. punctiferalis was recorded during 50th SMW. The peak population of A. janata and S. litura was noticed in 35th to 37th SMW and 39th to 41st SMW, respectively. Evening relative humidity exhibited a negative and significant correlation with populations of E. flavescens (r = -0.744) and D. punctiferalis (r = -0.732) both. The larval population of A. janata had a positive and significant correlation with rainfall (r = 0.710). The population of S. litura showed a positive and significant correlation with bright sunshine hours (r = 0.830).
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