STUDIES ON TAXONOMY, SEASONAL INCIDENCE AND MANAGEMENT OF MAJOR INSECT PESTS OF SESAMUM (Sesamum indicum L.)
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Date
2022-08-17
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guntur
Abstract
An experiment entitled “Studies on Taxonomy, Seasonal incidence and
Management of Major Insect Pests of Sesamum (Sesamum indicum L.)” was
conducted at Agricultural College Farm, Naira, during rabi, 2020-2021. Collection,
Identification and taxonomical description of major insect pests of Sesamum, to study
the seasonal incidence of major insect pests on Sesamum and to evaluate the efficacy
of certain insecticides against major insect pests on Sesamum were the objectives of
the investigation.
From the survey carried out in 3 mandals of Srikakulam district and in
experimental plot, two major species of leafhoppers i.e., Hishimonus phycitis
(Distant) and Orosius orientalis (Mastumura) were identified in large populations on
Sesamum causing economical damage. The line diagrams of important male genitalia
structures along with colour photographs were depicted in detail.
Cheatotaxy of Antigastra catalaunalis larva was described. On prothorax
Microscopic seta MXD1, dorsal setae D1 and D2 anterior dorsal setae XD1 and XD2
are distinct. On mesothorax dorsal setae D1 and D2 and microscopic setae MXD1 and
MXD2 are distinct. Microscopic setae MV1, MV2 and MV3 are distinct. Third
abdominal segment is with dorsal seta D1 positioned antero dorsally from D1. Sub
dorsal setae SD1 and SD2 present above the spiracle. Lateral seta L1 present nearer to
the spiracle. Subventral setae SV1 and SV2 are distinct. Crochets on abdominal
prolegs are uniordinal mesoseries. Whitefly (Bemisia tabaci) adults are about 1 mm
long, the males are slightly smaller than the female. The body and both pairs of wings
are covered with a powdery, waxy secretion, body yellow, wings hyaline white to
slightly yellowish in colour. Nymphs are flattened and oval in shape, yellow-white in
colour and have two yellow spots and are scale like measuring 0.3-0.6 mm.
The relation between abiotic factors and insect pests which were identified on
Sesamum crop in experimental plot was studied using simple correlation and multiple
regression analysis. The correlation data indicated that all three pests viz., leafhoppers
(Hishimonus phycitis), whitefly (Bemisia tabaci) and capsule borer (Antigastra
catalaunalis) showed significant positive correlation with maximum temperature (r =
0.623, 0.821, 0.729) and minimum temperature (r = 0.283, 0.120, 0.33) respectively.
While, negatively correlated with morning RH (r = -0.183, -0.097, -0.436) and
evening RH (r = -0.165, -0.182, -0.078) respectively and rainfall showed nonsignificant
correlation (r = 0.0) with insect pests. The predicted mean pest population
per plant was represented by using multiple regression analysis.
Thiamethoxam 25WG @ 0.25 g/l was very efficient against both the sucking
pest population i.e., leafhoppers (Hishimonus phycitis) and whitefly (Bemisia tabaci)
recording 76.7% and 50.2% reduction in population over the control respectively.
Thiamethoxam 25WG @ 0.25 g/l was also proved as good insecticide against
Sesamum phyllody by recording lowest overall PDI of 5.66 after two sprays. Results
also revealed that Chlorantraniliprole 18.5 SC @ 0.3 ml/l was highly effective against
Antigastra catalaunalis recording lowest larval population (1.30/plant) and lowest
capsule damage (1.25%).
Considering the yield and economics parameters Thiamethoxam 25WG @
0.25 g/l was best treatment recording highest seed yield of 6.50 q/ha and highest B:C
ratio (1: 4.7).
Description
STUDIES ON TAXONOMY,
SEASONAL INCIDENCE AND
MANAGEMENT OF MAJOR
INSECT PESTS OF SESAMUM
(Sesamum indicum L.)