Seasonal incidence and estimation of losses due to insect pests in sorghum [Sorghum bicolor (L.)Monch]
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Date
2016
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Publisher
MPUAT, Udaipur
Abstract
The investigation on, “Seasonal incidence and estimation of losses due to
insect pests in sorghum [Sorghum bicolor (L.) Monch]” was carried out at the
Instructional Farm, Rajasthan College of Agriculture, Udaipur during kharif , 2015.
The populations of shoot fly (Atherigona soccata Rondani), stem borer (Chilo
partellus Swinhoe), sorghum midge (Contarinia sorghicola Coquillet), earhead bug
(Calocoris angustatus Lethiery), armyworms (Mythimna separata Walker), kharif
grasshopper (Hieroglyphus nigrorepletus Bolivar) and shoot bug (Peregrinus maidis
Ashmead) were recorded in significant numbers on sorghum crop during the growing
season. The investigation revealed that the incidence of shoot fly commenced in the
fourth week of July; those of stem borer, kharif grasshopper and shoot bug in the
second, third and fourth week of August in a respective manner. The incidence of
armyworm was recorded in the first week of September; whereas, sorghum midge and
earhead bug, both were recorded in the second week of September. The stem borer
exhibited a significant negative correlation with mean relative humidity (r = -0.94);
likewise, sorghum midge showed a significant negative correlation with mean relative
humidity (r = -0.67).
The insect pest infestation significantly influenced the yield attributing
characters and sorghum grain yield. The insect pest infestation caused reduction in
mean height of plant (5.53%), test weight of 1000 sorghum grains (13.41%), mean
grain yield per plant (14.19%) and mean grain yield per plot (13.89%) in unprotected
plots, which was equivalent to a loss of 4.13 q ha-1.
Among the eight sorghum genotypes evaluated against shoot fly, the
genotypes CSV-27, SPV-2165 and PC-1080 exhibited minimum average percentage
dead hearts (20.00%) on the 14th day after germination. Similarly, the genotypes
CSV-27(31.37%), SPV-2165 (31.37%) and PC-1080(33.33%) resulted in minimum
average percentage dead hearts on the 21st day after germination. The genotype, CSV-
27 with 46.67 per cent dead heart was significantly superior over the susceptible
check CSV-20 on 28th day after germination.
Description
Seasonal incidence and estimation of losses due to insect pests in sorghum [Sorghum bicolor (L.)Monch]
Keywords
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Citation
Spana and Lekha, 2016