Bio-ecology and Management of Major Insect Pests of Sweet Basil (Ocimum basilicum L.: Lamiaceae)
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Date
2018
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Journal ISSN
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Publisher
MPUAT, Udaipur
Abstract
Bio-ecology and Management of
Major Insect Pests of Sweet Basil (Ocimum basilicum L.:
Lamiaceae)
Ashok Kumar* Prof. R. Swaminathan The present investigations on “Bio-ecology and Management of Major Insect
Pests of Sweet Basil (Ocimum basilicum L.: Lamiaceae)”, were carried out at
Agronomy farm and in the Department of Entomology, Rajasthan College of
Agriculture, MPUAT, Udaipur during the kharif seasons from 2016 and 2017.
During the two consecutive crop seasons (kharif, 2016 & 2017), the major
insect pests infesting sweet basil were the semiloopers, leaf folder/ webber, tobacco
caterpillar, gram pod borer, hairy caterpillar, leaf & flea beetles, thrips, lace bug,
whitefly, jassids, seed bug, aphids, chafer beetles and foliage-feeding weevils. The
associated natural enemies included the spiders, wasps, coccinellids, robber fly,
predatory pentatomid bug and syrphid fly in sweet basil during the study.
The peak mean populations (per five plants) of semiloopers (32.83) and jassids
(33.33) was in second week of September; leaf folder/ webber (8.42), tobacco
caterpillar (10.42) and hairy caterpillars (8.75) in the last week of August; gram pod
borer (7.08) and lace bug (38.83) in the second week of August; leaf & flea beetles
(5.75) in the third week of August; the seed bug (10.33) in the last week of July; and
the thrips (38.00), whiteflies (33.33) and aphids (41.25) was peaked in the third week
of September on sweet basil during 2016. In kharif, 2017 the peak population of
semilooper (11.83), thrips (9.17) and whiteflies (12.00) was in third week of August;
* Ph.D. Scholar, Department of Entomology, Rajasthan College of Agriculture, MPUAT, Udaipur
** Professor, Department of Entomology, Rajasthan College of Agriculture, MPUAT, Udaipur
leaf folder/ webber (35.00) and lace bug (30.17) in the third week of September;
tobacco caterpillar (5.92), hairy caterpillar (12.92) and jassids (14.00) in the first week
of September; leaf & flea beetles (3.67) and seed bug (8.83) in the last week of July;
the gram pod borer (8.83) in the first week of August; while aphids (28.17) peaked in
the first week of October.
The mean population of thrips (r = 0.52), (r = 0.54) and whiteflies (r = 0.53), (r
= 0.52) had significant positive correlation with the mean atmospheric temperature
during both the crop season, respectively, but aphids (r = 0.56) was significant and
positive only in 2016. The tobacco caterpillar (r = - 0.58), (r = -0.65) and lace bug (r =
-0.66), (r = - 0.56) showed significant negative correlation for 2016 and 2017 with
respective values; while the leaf folder/ webber (r = - 0.70), gram pod borer (r = -
0.86) and leaf & flea beetles (r = -0.65) only in 2016 and hairy caterpillar (r = - 0.61);
seed bug (r = -0.58) and jassids (r = - 0.54) in 2017 showed significant negative
correlation with the mean atmospheric temperature. The mean relative humidity
showed significant positive correlation for the leaf folder/ webber (r = 0.64), (r =
0.61); gram pod borer (r = 0.75), (r = 0.65); leaf & flea beetles (r = 0.73), (r = 0.74);
lace bug (r = 0.75), (r = 0.56) and seed bug (r = 0.65), (r = 0.76) during both the years
with respective values, but tobacco caterpillar (r = 0.56) and jassids (r = 0.64) only in
2017; whereas, with thrips (r = -0.54), whiteflies (r = -0.58) and aphids (r = -0.72) a
significant negative correlation was observed during 2016. The population of seed
bug (r = 0.74), (r = 0.62) had a significant positive correlation with total rainfall for
2016 and 2017 with respective values, but leaf & flea beetles (r = 0.67) only in 2017;
whereas, the whiteflies (r = -0.64), (r = - 0.67) and aphids (r = -0.55), (r = - 0.80)
showed significant negative correlation with total rainfall for 2016 and 2017 with
respective values; while, the semilooper (r = -0.55), thrips (r = -0.55), and jassids (r =
-0.53) a significant negative correlation with total rainfall only in 2016.
During 2016, among the insect pests of sweet basil, aphids had the maximum
seasonal mean population (18.05/ 5 plant), mean density (0.28) and relative density
(16.13%); while in 2017, the maximum seasonal mean population (14.62/ 5 plant),
mean density (0.21) and relative density (17.72%) were for lace bug. The Shannon-
Weiner Diversity Index values were 2.30 and 2.29 for 2016 and 2017, respectively.
As for the natural enemies, the spiders had the maximum seasonal mean
population (6.70 & 6.92/ 5 plant), mean density (0.09 & 0.09) and relative density
(57.26 & 59.63%) during kharif, 2016 and 2017 with respective values. The ShanonWeiner
Diversity Index values were 0.96 for kharif, 2016 and 0.95 for kharif 2017.
The coccinellids evinced significant positive correlation with the mean relative
humidity (r = 0.55), (r = 0.70) during both the years, respectively; but significant
negative correlation with the mean atmospheric temperature (r = -0.65) during kharif,
2016.
Among all the foliage feeding lepidopterans, the growth and development of
leaf folder/ webber, semilooper, tobacco caterpillar and gram pod borer were studied.
Of these, the life cycle was shortest for leaf folder/ webber (27.60 days) and the
longest for gram pod borer (43.90 days); the leaf webber developed through 5 larval
instars, while for the others, 6 larval stages could be distinctly identified. The total
larval period was 12.10 days and the different instars took 3.50, 1.50, 1.70, 2.20 and
3.20 days respectively for the 1st through 5th instars for the leaf folder/ webber P.
panopealis. The time taken for total growth and development in decreasing order was
gram pod borer (43.90 days), tobacco caterpillar (37.40 days), semilooper (32.38
days) and leaf folder/ webber (27.60 days). The morphometric data were measured as
larval body length, width; pupal length, width and adult body length and wing span.
The overall efficacy of the bio-rational insecticides evaluated after two sprays
indicated that among all the bio-rational insecticidal treatments the, Azadirachtin
1500 ppm (1%) was most effective at 3, 5 and 7 days after first spray against sap
sucking insect pests as well as defoliators; while the, minimum per cent mean
population reduction was recorded in Nicotine Sulfate 40 S (0.02%) against all the
insect pests occurred on sweet basil during kharif, 2016 and 2017. After second spray
the Spinosad 45 SC (150ml/ha) was superior among all the bio-rational insecticidal
treatments against defoliator insect pests at 3, 5 and 7 days; whereas, the Bacillus
thuringiensis (1.5kg/ha) was least effective at 3, 5 and 7 days after second spray
during both the years 2016 and 2017.
The maximum seed yield was recorded when sweet basil crop was treated with
NSKE (5%) as first spray followed by Spinosad 45 SC (150ml/ha) as second spray
during both the years, the seed yield during 2016 and 2017 with NSKE (5%) +
Spinosad 45 SC (150ml/ha) was recorded 0.75 and 1.45 kg/ plot, respectively. Among
the treatments, the lowest yield was recorded for the treatment of sweet basil with
Nicotine Sulfate 40 S (0.02%) as first spray followed by Deltamethrin 2.8 EC
(0.015%) as second spray with seed yield of 0.50 and 0.98 kg/ plot during the crop
seasons of kharif, 2016 and 2017, respectively.
Description
Bio-ecology and Management of Major Insect Pests of Sweet Basi
Keywords
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Citation
KUmar. A, and Swaminathan. R