Studies on varietal screening, biology and management of rice weevil, Sitophilus oryzae (L.) on stored wheat
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Date
2018
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CCSHAU
Abstract
The studies on rice weevil, Sitophilus oryzae (L.) with reference to biology on wheat variety
WH1105, screening of 15 different varieties of wheat and management through seed protectants were
carried out at Storage Entomology Laboratory, Department of Entomology, CCS HAU, Hisar during
2017. Studies on biology of S. oryzae revealed that the eggs of this species were spherical with one end
pointed and another rounded, translucent and white in colour and laid singly. The average incubation
period of eggs was 5.14 days. There were four larval instars and grubs were apodous, stout, short and
yellowish-white in colour with brown-coloured head and pupa was soft, exarate and white to
yellowish-white in colour. The average larval and pupal period varied from 28.20 to 32.20 days and an
average of 29.72 days under laboratory conditions. Adult male and female lived for 32.28 and 38.46
days, respectively. The average total life cycle of S. oryzae was observed as 34.88 days. The average
fecundity was recorded as 189.90 eggs per female. The oviposition period was observed as 24.80 days.
Average male and female ratio was recorded as 1:1.19 indicating little dominance of female over male
population. Studies on varietal screening revealed that none of the wheat variety found free from
infestation of S. oryzae. However, varieties WH283, WH711, DBW17, WH1080, and WH157 were
found moderately preferred. Varieties WH-2967, WH542, WH1025 and were found less preferred.
Varieties WH1105, WH1124, WH1142, and C306 were least preferred and WH147 was found to be
most preferred as the number of eggs, number of adults emerged, grain damage and weight loss was
maximum followed by DPW62150 and PBW343. Studies on efficacy of seed protectants revealed that
all the seed protectants resulted in significant difference in their effectiveness against S. oryzae.
However, neem seed kernel powder, neem oil and custard apple seed powder were found very effective
in controlling rice weevils followed by mustard oil, groundnut oil, mustard oil + turmeric powder and
groundnut oil + turmeric powder whereas saw dust was found least effective as seed protectant
followed by turmeric powder. No adverse effect of these seed protectants was observed on the
germination of wheat seed at different intervals whereas the germination was observed to be maximum
in the treatment of neem seed kernel powder and neem oil.
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