Eco-friendly Management of Major Insect Pests of Cabbage, Brassica oleracea var. capitata Linn.
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Date
2022
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Abstract
The investigation on ‘Eco-friendly Management of Major Insect
Pests of Cabbage, Brassica oleracea var. capitata Linn’ under semi-arid
condition was conducted at Horticulture Farm, S.K.N. College of
Agriculture, Jobner (Rajasthan) during Rabi, 2021-22.The initiation of
aphid population recorded in the third week of December which reached
peak in third week of February (8th SMW) (160.4 aphid/plant), while, the
initiation of diamondback moth population recorded in the third week of
December (51nd SMW) which reached its peak in fourth week of
February, i.e. 9
th SMW (4.5 DBM larvae/10 plants) when maximum
temperature, minimum temperature and relative humidity was 31.0 and
8.1°C, 50 per cent and sun shine (9.5 hrs), respectively and gradually
declined thereafter. Flea beetle, the initiation of flea beetle population
recorded in the first week of January (1st SMW) which reached its peak
in fourth week of February, (10.1 flea beetle/10 plants) and gradually
declined thereafter. Painted bug, the initiation of painted bug population
recorded in the fourth week of November (48th SMW) which reached its
peak in fourth week of February, (5.2 painted bug/10 plants) and
gradually declined thereafter. The natural enemy of Coccinella
septempunctata, the initiation of C. septempunctata population recorded
in the second week of December (50
th SMW) which reached its peak in
fourth week of February, (3.9 /10 plants).
The relationship between aphid L. erysimi, with maximum
temperature, minimum temperature, and relative humidity had showed
negative correlation (r = -0.193, r = -0.149 and r = -0.139),
diamondback moth, Plutella xylostella (L.) and painted bug Bagradacruciferarum (Kirk.) had showed that positive correlation (r = 0.446, r =
0.308, r = 0.709 and r = 0.783, r = 0.419, r = 0.798) with maximum
temperature, minimum temperature and sun shine, respectively, while,
had showed negative significant correlation (r = -0.588 and r = -0.798,
respectively) with relative humidity; flea beetle, Phyllotreta cruciferae
(Goeze.) population with maximum temperature and sun shine had
showed positive correlation (r = 0.188 and r = 0.580), while relative
humidity had showed negative correlation (r = -0.344). While, maximum
temperature, minimum temperature and sun shine population showed
positive correlation (r=0.211, r= 0.151 and r= 0.483) with Coccinella
septempunctata and negative non-significant correlation with abiotic
factor viz., relative humidity.
The experiment on effect of intercrops on the incidence of major
insect pests showed that all intercrop combinations harboured the
lesser population of major insect pests (aphid and diamondback moth)
than the sole crop. The cabbage + onion and cabbage + tomato
intercrop combinations were significantly less conducive to aphid and
diamondback moth infestation as compared to other intercrop
combinations. The maximum cabbage equivalent yield (173.72 q/ha)
was obtained from the treatment onion as an intercrop at 4:1 ratio
which was significantly superior over rest of the treatments except the
treatment tomato as intercrop which recorded in cabbage with
equivalent yield (149.05 q/ha).
The efficacy of nine biopesticides tested against major insect pests
of cabbage revealed that azadirachtin 1% EC proved to be the most
effective followed by azadirachtin 0.03% EC and Neem oil. The
treatments of Beauveria bassiana 1.15 WP, NSKE 5% and
Metarhizium anisopliae 1.15 WP stood in middle order of efficacy
followed by the treatments of Karanj oil, and Verticillium lecanii 1.15
WP which were proved to be least effective against aphid and
diamondback moth of cabbage. The maximum per cent avoidable loss
was found to be (18.69%) in the treatment of azadirachtin 1% EC,
whereas, minimum in untreated control. The highest benefit cost ratio
was found in the azadirachtin 1% EC (8.79) followed by NSKE and
azadirachtin 0.03% EC. The yield showed that azadirachtin 1% EC
treated plants maximum yielded and it was followed by azadirachtin
0.03% EC and Neem oil.