Studies on management of aphid (Lipaphis erysimi Kalt.) on mustard
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Date
2020
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DRPCAU, Pusa
Abstract
In order to develop strategies for management of mustard aphid (Lipaphis
erysimi Kalt.), an investigation entitled Studies on Management of Aphid (Lipaphis
erysimi Kalt.) on Mustard was carried out at the Research farm, Tirhut College of
Agriculture, Dholi, Muzaffarpur, Bihar (India). A series of experiments were
conducted during two consecutive rabi seasons during 2017-18 and 2018-19. Results
pertaining to different aspects of present study viz., population dynamics of mustard
aphid (Lipaphis erysimi Kalt.) under different environmental factors, exploring the
possibility of management of aphid on mustard through manipulations in dates of
sowing, screening of mustard genotypes for resistance against mustard aphid, relative
field efficacy of some synthetic insecticides against mustard aphid (Lipaphis erysimi
Kalt.) are mentioned below:
The incidence of aphid started from fourth standard week for both the years.
Maximum number of mustard aphids attack on top 10 cm inflorescence of mustard
was observed during the tenth standard week in both the years (222.4 in 2017-18 and
198.8 in 2018-19). However, the insect vanished in the thirteenth standard week for
both the years. During first year (2017-18), maximum as well as minimum
temperature, RH were correlated positively with mustard aphid but in 2018-19,
maximum temperature, rainfall and no. of rainy days showed a negative impact on the
insect outbreak; minimum temperature, RH (0700 hr and 1400 hr) were correlated
positively. The R2 for mustard aphid in 2017-18 and 2018-19 were reported to be 78.4
% and 52.4 % respectively.
Two natural enemies namely- Coccinella septempunctata and Syrphid fly
were witnessed during both the experimental years. The predator incidence was from
sixth standard week and their peak was observed in the tenth standard week
(Coccinella septempunctata, 5.40 and Syrphid fly, 4.20) during the first year.
However, in 2018-19, the population of natural enemies were at their peak in ninth
standard week (Coccinella septempunctata 3.6 and Syrphid fly 2.4). Meanwhile, they
disappeared in thirteenth standard week for both the years. In 2017-18, RH (1400 hr)
was negatively correlated while RH (0700 hr), temperature (maximum and minimum)
was correlated positively.
In 2018-19, maximum and minimum temperature, rainfall, number of rainy
days had a negative correlation but RH (0700 hr and 1400 hr) was found positively
ii
correlated. The R2 for Syrphid fly and Coccinella septempunctata in 2017-18
was 81.5 and 74.9 respectively while for 2018-19 the R2 was 76.6 % for Syrphid fly
and 74.1 % for Coccinella septempunctata.
By manipulating the dates of sowing, it was observed that the crops sown on
last date possessed maximum mean number of aphid infestation for both the years
(23.15 in 2017-18 and 44.64 in 2018-19). The yield was reported maximum on the
crops sown on first date i.e. October 10th 1277.50 kg/ha in 2017-18 and 1245.00 kg/ha
in 2018-19 along with the test weight of 250 seeds.
It was observed that the crops sown earlier were reported with minimum mean
number of aphids for both the years.
While screening forty advanced genotype, not a single genotype/variety was
found highly resistant in two years of experimentation. The mean number of aphids
per 10 cm inflorescence ranged from 91.5 to 311.1 during 2017-18 while in second
experimental year i.e. 2018-19, the mean number ranged in between 93.5 to 327.0.
DRMR-1165-40 was reported to have minimum infestation both the years (i.e., 2017-
18 and 2018-19). Maximum genotypes in both years of investigation were found to be
susceptible, followed by moderate and highly susceptible categories.
The bio efficacy of newer pesticides against mustard aphid was tested during
two consecutive rabi seasons of 2017-18 and 2018-19. The trend of mustard aphid
population (mean number) obtained was: T1 (78.00 to 70.00), in T2 (84.00 to 77.40),
T3 had a reduction from 86.80 to 79.80, T4 (89.00 to 82.2), in T5 92.00 to 84.80, T6
and T7 were reduced from 91.30 to 85.50 and 95.00 to 87.20 respectively.
Meanwhile, in T8 the number of insects observed were maximum (134.00 to 137.96)
during 2017-18. Meanwhile, during 2018-19, the mean number of aphid followed the
trend as: Thiamethoxam (86.00 to 77.25) followed by Indoxacarb (88.00 to 81.78)
followed by Novaluron (90.00 to 84.42).Spinosad (93.00 to 86.40) remained in the
middle followed by Dimethoate (92.00 to 86.97), YSBE (95.00 to 90.13) and Neem
Oil (95.00 to 90.87). In the untreated control, the mean number of aphid population
range was as: 123.00 to 127.19.
The yield in T1 (1230 kg/ha) during 2017-18 and (1171 kg/ha) in 2018-19 was found
to be maximum along with the test weight (250 seed in gram) 1.080g in 2017-18
and 1.040 g in 2018-19. All the treatments showed reduction in mean number
of mustard aphids except for the untreated control i.e. treatment, T8.