STUDIES ON BIONOMICS OF BRINJAL SHOOT AND FRUIT BORER (Leucinodes orbonalis Guenée), ITS MANAGEMENT THROUGH NEWER INSECTICIDES AND THEIR RESIDUES IN/ON BRINJAL (Solanum melongena L.) FRUITS
Loading...
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Dr.RPCAU, Pusa
Abstract
The total 11 species of pests belongs to the 11 genera, 9 families and 3 orders
were recorded associated with the brinjal ecosystem. And also noticed several natural
enemies belongs to 9 species, 8 genera, 6 families and 5 orders. Whereas, the
incidence of L. orbonalis were also observed in Solanum tuberosum, S. nigrum,
S. indicum, S. torvum and S. lycopersicon which belongs to family Solanaceae.
And also studied life cycle of L. orbonalis under laboratory conditions during
2019-20 and 2020-21 in Rabi and Zaid/ summer seasons. The incubation period was
recorded around 3.93 and 4.25 days in Rabi, but 3.66 and 3.86 days in Zaid/ summer
in both the years. The total larval period was around 15.86 and 16.32 days in Rabi and
whereas, 11.37 and 11.83 days in Zaid/ summer. Though, the pupal period was
recorded around 5.76 and 5.97 days in Rabi and 5.08 and 5.28 days in Zaid/ summer.
The longevity of the male moth was recorded 4.05 and 3.73 days in Rabi, but 3.21 and
3.41 days in Zaid/ summer and female moth was recorded around 5.50 and 5.35 days
in Rabi still 4.40 and 4.55 days in Zaid/ summer. The pre-oviposition was also
observed around 1.51 and 1.74 days in Rabi and 1.07 and 1.30 days in Zaid/ summer.
Oviposition period was 2.95 and 3.07 days in Rabi and 1.65 and 2 days in Zaid/
summer during both the years. The studies of population dynamics of brinjal shoot
and fruit borer during Rabi and Zaid/ summer seasons of 2019-20 and
2020-21 revealed that, the peak shoot infestation was recorded around 9th and 11th
week after transplantation during Rabi and Zaid/ summer, similarly the fruit
infestation reached its peak at 21st and 21st on number basis, respectively whereas, on
the basis of weight 9th and 16th week after transplantation. The maximum temperature
was the only abiotic factors significantly (positive) correlated with shoot and fruit
infestation of L. orbonalis in both the seasons. While, other weather parameters like
minimum temperature, morning and evening relative humidity, rainfall, evaporation
and sunshine were either significantly or non-significantly (positive or negative)
correlated with shoot and fruit infestation.
Bio-efficacy of new insecticides- chlorantraniliprole 18.5% SC @ 40 g a.i.ha-1
was significantly superior to all the insecticidal treatments and also recorded
maximum fruit yield (295 q ha-1). It was followed by emamectin benzoate 5% SG @
10 g a.i. ha-1 (259.25 q ha-1), spinosad 45% SC @ 84 g a.i. ha-1 (256 q ha-1), lambdacyhalothrin
5% EC @ 15 g a.i. ha-1 (219.25 q ha-1), thiacloprid 21.7% SC @ 180 g a.i.
ha-1(209.5 q ha-1), dimethoate 30% EC @ 200 g a.i. ha-1 (171.5 q ha-1), pyriproxyfen
5% EC + fenpropathrin 15% EC @ 150 g a.i. ha-1 (159.75 q ha-1), betacyfluthrin
8.49% + imidacloprid 19.81% OD @ 60 g a.i. ha-1 (138.5 q ha-1) and were at
statistically at par with each other. The maximum B: C ratio (1: 2.86) was obtained in
chlorantraniliprole compared to other treatments like emamectin benzoate (1: 2.63),
spinosad (1: 2.38), lambda-cyhalothrin (1: 2.24), thiacloprid (1: 1.90), dimethoate
(1:1.73), pyriproxyfen + fenpropathrin (1: 1.57) and betacyfluthrin + imidacloprid
(1: 1.44).
Quantitative estimation of the residues of chlorantraniliprole in/on brinjal was
done by HPLC. The samples of brinjal were processed using QuEChERS technique.
The mean recovery of chlorantraniliprole was found 80.92 to 82.07 per cent,
respectively. The mean recoveries of matrix matched standards were about 92.77 to
95.20 per cent. The matrix effect (%) were -13.60, +11.9, +1.22, -9.28 and +17.05 for
different concentrations viz., 2, 1, 0.5, 0.1 and 0.05 μg ml-1. The LOQ was observed to
be 0.05 mg kg-1.
The mean initial deposit of chlorantraniliprole @ 40 g a.i. ha-1 was obtained to
be 0.43 mg kg-1 and 0.92 mg kg-1 @ 80 g a.i. ha-1. The residues of chlorantraniliprole
was found to be dissipated to a mean level of 0.26 mg kg-1 and 0.54 mg kg-1 one day
after spraying which shown a dissipation 39.53 and 41.30 per cent residues at single
as well as double doses. The mean level of residue was found to be 0.15 mg kg-1, 0.27
mg kg-1. It showed per cent dissipation about 65.12 and 70.65 per cent residues in 3
days after spray. The mean level of residue was found to be 0.10 mg kg-1 and shown a
dissipation about 89.13 per cent in 5 days after spray at double dose. The residues
were found below the limit of quantification (LOQ) in 5 and 7 days after spray at
single and double doses.
The T1/2 of chlorantraniliprole were calculated to be 0.974 and 1.610 days
when applied at single and double doses after 3rd spray on brinjal. The mean initial
deposits of chloantraniliprole was observed to be below the MRL in one day after
spray at both the doses on brinjal.
The mean initial deposit of washing effect was obtained to be 0.43 mg kg-1 of
chlorantraniliprole which was reduced to 0.36 mg kg-1 for single dose in zero day
after spray. Whereas, the mean initial deposit was found to be 0.26 mg kg-1 which was
reduced to 0.23 mg kg-1 for single dose in one day after spray. For double dose, the
initial deposit was found to be 0.92 mg kg-1 which was reduced to 0.69 mg kg-1 in
zero day after spray. Though, the initial deposit was gained to be 0.54 mg kg-1,
it reduced to 0.42 mg kg-1 for double dose in one day after spray.