Crop Loss Estimation and Management of Earhead Caterpillar Helicoverpa armigera (Hubner) on Kharif Sorghum
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Date
2011
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UAS, Dharwad
Abstract
Investigations on crop loss estimation, effect of different dates of sowing and
management of sorghum earhead caterpillar, Helicoverpa armigera (Hubner) were
undertaken at Main Agricultural Research Station, University of Agricultural
Sciences, Dharwad during 2009-10 kharif season.
Crop loss estimation studies under natural condition revealed that, CSH-14
recorded least number of larvae (0.33/earhead) and highest grain yield (44.1 q/ha).
Whereas minimum per cent earhead damage (1.33%) was recorded on both CSH-14
and CSH-16 cultivars. Overall an extent of 17.42 per cent yield loss can be avoided
when protection measures were taken. Under artificial condition as the number of
larvae released per earhead increased simultaneously reflected in reduction of grain
yield. Low grain yield per earhead was recorded when larvae were released at both
stages i.e., flowering and milky stages as compared to larvae released once at each
stage.
Studies on effect of different dates of sowing indicated that in early date of
sowing (12th June 2010) CSH -14 recorded minimum larval load (2 larvae/earhead)
and earhead damage (11.33%) with highest grain yield of 39.81 q/ha. Whereas late
sowing (24th July 2010) recorded 4.77 larvae/earhead and 43.00 per cent earhead
damage with grain yield of 12.90 q/ha. The similar trend was exhibited in CSH-16
under early and late sowing.
Among different insecticides tested spinosad 45 SC (0.1 ml/l), novaluran 10
EC (1 ml/l) and azadirachtin 5 per cent (5 ml/l) emerged as superior by
recording 72.0, 66.0 and 63.0 per cent population reduction of H. armigera and
produced a grain yield of 43.46, 42.23 and 41.16 q/ha, respectively. Maximum gross
and net returns were recorded with two sprays of spinosad 45 SC with Rs. 35637.2
and Rs. 22140.2 per ha, respectively.
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Keywords
Agricultural Entomology