Population dynamics of paddy borers and biology of pink stem borer, Sesamia inferens (Walker)
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Date
2005
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Publisher
CCSHAU
Abstract
Population dynamics of paddy borers and biology of pink
stem borer were carried out in the field, laboratory and
screen-house at CCS Haryana Agricultural University, Rice
Research Station, Kaul during Kharif 2004. The population of
borers fluctuated in different periods during the season. The
maximum number of eggs and pupae were recorded in the first
week of October while the maximum larvae were recorded in
the third week of October indicating that population of borers
(yellow stem borer and pink stem borer) build up late in season
among the borers, yellow stem borer pre-dominated throughout
the season while pink stem borer was dominating towards the
maturity of the crop (2.26-23.01%). Though the egg parasitism
was good (62.0%), larval and pupal parasitism was almost nil.
Telenomous dignus was the dominating egg parasitoid. The
maximum temperature, minimum temperature and evening
relative humidity exhibited a negative relationship with total
larvae. The relationship between mortality of larvae and
maximum temperature was positive while it was negative with
morning relative humidity. The pink stem borer eggs were
thrust between the leaf sheath and stem. The third leaf sheath
was preferred most on which maximum (80.03%) eggs were
recorded. The incubation period was 5.34±0.10 days. The borer
completed its post embryonic development in 78.76 (males),
82.5 days (females) and passed through eight instars with
36.00±0.75, 32.33±1.5 and 94.05±7.4 per cent survival,
pupation and moth emergence, respectively. The mean larval
and pupal period (male and female) was 67.44±0.55 and
9.08±0.19, 12.83±0.28 days, respectively. The average longevity
of male and female was 10.9±0.48 and 11.4±0.75 days,
respectively. The average fecundity was 332.1±16.99 eggs and
hatchability 87.04±3.18 per cent.