Efficacy of bioformulations against cutworm, Agrotis spp. (Lepidoptera: Noctuidae)
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Date
2019-07-15
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palampur
Abstract
The present investigation entitled “Efficacy of bioformulations against cutworm, Agrotis spp.
(Lepidoptera: Noctuidae)” was undertaken during 2018-2019 in the Department of Entomology,
CSK HPKV, Palampur to assess the intrinsic toxicity of different bioformulations viz., Dashparni
ark, Neemastra, Agniastra, Brahmastra and garlic+ ginger+ mint mixture at concentration ranges
from 2.5 to 40 per cent against the first, second and third instar larvae of A. ipsilon by leaf dip
methods of bioassay. Based on LC50 values, the order of toxicity of bioformulations against first,
second and third instar was observed as: Dashparni ark (8.28, 9.82, 11.69%) > Brahmastra
(10.38, 11.58, 15.08%) > Agniastra (11.19, 13.21, 17.32%) > Neemastra (14.53, 15.43, 20.40%)
> garlic + ginger + mint mixture (16.66, 19.01, 23.04%, respectively). The feeding inhibition (FI)
studies of different bioformulations concentration ranges from 1.5 to 24 per cent were evaluated
against the fourth, fifth and sixth instar larvae of A. ipsilon. Based on FI50 values, the order of
feeding inhibition of bioformulations tested against the fourth, fifth and sixth instar larvae was
observed as: Dashparni ark (5.11, 5.53, 7.08%) > Brahmastra (5.54, 5.76, 7.29%) > Agniastra
(5.76, 6.17, 7.46%) > Neemastra (6.29, 6.67, 7.85%) > garlic + ginger + mint mixture (6.90, 7.39,
8.89%, respectively). Laboratory studies revealed that at recommended concentration (10%) of
different bioformulations used against fourth instar larvae impaired the normal development of A.
ipsilon by prolonging the larval period of fourth, fifth and sixth instar i.e. 3.55, 5.50 and 8.65 days
in Dashparni ark as compared to control 2.45, 4.50 and 7.65 days, respectively. In Dashparni ark,
there was 7.84 per cent increase in pupal period over control, reducing male and female
longeivity, shortening the oviposition period and reducing the fecundity by 13.3 per cent in
Dashparni ark i.e. 1085 eggs as compared to 1250 eggs in control. Evaluation of bioformulations
against A. ipsilon in pot experiment under laboratory conditions revealed that the application of
bioformulations (10%) in the potato seedling tray reduced the plant cut by fourth instar larvae to
69.24 per cent in Dashparni ark followed by Brahmastra (61.53%), Agniastra (49.24%),
Neemastra (41.53%) and garlic + ginger + mint mixture (29.24%) over control. Based on the
outcome of the present study, it was concluded that organic products have potential in causing
mortality in the early stages of larval development besides impairing growth and development of
later instar larvae. Among five organic products, Dashparni ark was observed to be the most
effective treatment against the test insect.