Studies on the economic threshold and management of coriander aphid, Hyadaphis coriandri (Das) on coriander (Coriandrum sativum L.)
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Date
2007
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Publisher
CCSHAU
Abstract
Studies on the economic threshold and management of
coriander aphid, Hyadaphis coriandri (Das) on coriander (Coriandrum
sativum L.) was undertaken during ‘rabi’ 2006-07. Two experiments viz., “To
determine the economic threshold for Hyadaphis coriandri (Das) on
coriander” and “To study the effect of different management practices on the
incidence of Hyadaphis coriandri (Das)” were conducted.
The experiment to determine the economic threshold (ET) for
H. coriandri (Das) on coriander var. Hisar Anand comprised of eight
exposure periods to aphids. The crop was protected from aphids (using
carbaryl 50 WP @ 1kg/ha), when 5 to 10 aphids per 10cm main
shoot/umbel was observed on 10 per cent of plants. The benefit cost ratios
were worked out on the basis of monetary returns over control and plant
protection cost. The economic threshold for H. coriandri infesting coriander
crop var. Hisar Anand under Hisar, Haryana agro-climatic conditions were
worked out with the help of linear regression equation Y= . ET for
aphid was worked out to be 25.88 per 10cm main shoot/umbel on the basis
of benefit cost ratio, which was the highest (14.79) in treatment where ten
days exposure to aphids was given.
Studies conducted on the effect of date of sowing and
fertilizer/manure application were undertaken in an experiment laid out in
split plot design. While date of sowing (two dates) was kept as main plot,
fertilizer/manure application (four levels) was put in sub-plots. The aphids
started appearing from the middle of February, 07 and its peak was
observed during the second week of March, 07. The maximum number of
aphids (19.07 aphids/10 cm main shoot/umbel) was recorded in treatment
D2 (3rd week of November) as compared to 18.32 aphids per 10 cm main
shoot/umbel in treatment D1 (1st week of November). The highest aphid
population of 19.50 aphids per 10 cm main shoot/umbel was observed in
treatment F2 (100 kg N/ha + 50 kg P2O5/ha). This was followed by
treatment F3 (50 kg N/ha + 25 kg P2O5/ha and FYM @ 10 tonnes/ha), F1
(FYM @ 20 tonnes/ha) and F4 (no fertilizer/manure application), harbouring
18.92, 18.32 and 18.05 aphids per 10 cm main shoot/umbel, respectively.
The data revealed that crop sown at normal date (D1: 1st week
of November) afforded the best figures with respect to height of the plant
(103.04 cm), number of primary branches per plant (6.57), number of
secondary branches per plant (18.57), number of umbels per plant (46.73),
number of seeds per umbel (42.57), test weight (16.89g) and seed yield
(18.00 q/ha). The corresponding figures for each of the traits in the crop
sown late (D2) were significantly lower.
The crop, where recommended doses of fertilizer (F2) were
applied, afforded the best figures with respect to height of the plant
(107.83cm), number of primary branches per plant (6.65), number of
secondary branches per plant (19.92), number of umbels per plant (47.67)
and seed yield (18.86 q/ha). On the other hand, the maximum number of
seeds per umbel (41.95) and highest test weight (16.98g) was observed in
the plots where only FYM (F1) was applied.
Description
Keywords
Coriander aphid, Coriander, Economic threshold, Management, Hisar Anand, Date of sowing, Fertilizer/manure application, Yield and yield attributes