Abstract
Spodoptera litura Fabricius (Noctuidae; Lepidoptera) is most damaging insect pest of various crops. Entomopathogens have
potential to manage insect pests by minimizing resistance and reducing health hazards associated with synthetic toxic
chemicals. The Nuclear polyhedrosis virus isolate of S. litura (V-SpltNPV) was isolated from infected larvae and presence of
viral occlusion bodies were confirmed using an inverted microscope. Laboratory as well as greenhouse experiment was
performed to evaluate the pathogenicity of V-SpltNPV. For laboratory studies,2nd, 3rd and 4th instar larvae of S. litura were
exposed to various concentrations (1×108
, 1×107
, 1×106
, 1×105
and 1×104 OBs/ml) of V-SpltNPV. The results revealed that
highest V-SpltNPV concentration (1×108 OBs/ml) caused 88.08% mean mortality while lower concentration (1×104 OBs/ml)
of V-SpltNPV resulted in lower mean mortality (58.75%) of 2nd instar larvae of S. litura. Larval mortality was enhanced with
increase in concentration of V-SpltNPV and mortality reduced with increase in age of S. litura larvae. Around 65.52% mean
mortality of 4thinstar was recorded against 1×108 OBs/ml which was reduced to 36.72% against 1×104 OBs/ml of V-SpltNPV.
In greenhouse experiment a combined application of spinosad with V-SpltNPV (1×108 OBs/ml) caused 92.98% mortality of
S. litura while individual application of V-SpltNPV (1×108 OBs/ml) resulted 39.65% mean mortality of 3rd instar larvae.
Similarly, individual exposure of spinosad caused around 42% mean mortality of 3rd instar larvae under semi-field conditions.
The native isolate V-SpltNPV have potential to be used in integrated manner with other IPM tactics to significantly reduce the
use of the insecticides.
Muhammad Bilal Ayyub, Ahmad Nawaz, Muhammad Dildar Gogi, Muhammad Jalal Arif, Luqman Amrao, Jam Nazeer Ahmad. (2020) COMPARATIVE TOXICITY ASSESSMENT OF NUCLEAR POLYHEDROSIS VIRUS AND SPINOSAD AGAINST Spodoptera litura (FABRICIOUS) IN SEMI FIELD CONDITIONS, Pakistan Journal of Agricultural Sciences, Volume 57, Issue 2.
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