BIOLOGY, POPULATION, DYNAMICS, VARIETAL SUSCEPTIBILITY AND CHEMICAL CONTROL OF LEAF WEBBER AND CAPSULE BORER, Antigastra catalaunalis (Duponchel) (PYRALIDAE: LEPIDOPTERA) ON SESAMUM (Sesamum indicum Linnaeus)
Loading...
Date
2003
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
AAU, Anand
Abstract
Sesamum leaf webber and capsule borer, Antigastra catalaunalis (Duponchel) have been studied in relation to its nature and extent of damage, biometrics and comparative biology on leaves and flowers of sesamum, preference for pupation and oviposition, natural enemies, population dynamics in relation to weather parameters, sensitivity to various sesamum genotypes/varieties and insecticides during 2000-01 at Gujarat Agricultural University, Anand Campus, Anand. The larvae fed on leaves, flowers and ovary and also bore into the capsule of sesamum. The damage ranged from 2.43 to 3.96 per cent on leaves, 23.11 to 46.96 per cent on flowers and 4.71 to 24.18 per cent on capsules in the field of sesamum crop. Eggs were oblong in shape and creamish colour. The larva was typically cruciform and passed through five instars. Pupa was cylindrical and adicticous and obtect type. The studies on biometrics and comparative biology indicated that the length and breadth of second instar larvae (2.89 ± 0.61 mm and 0.42 ± 0.02 mm, respectively) and third instar larvae (4.53 ± 0.59 mm and 0.55 ± 0.01 mm, respectively), length of fourth instar larvae (10.63 ± 0.46 mm), width of head capsule in third (0.47 ± 0.02 mm), fourth (0.65 ± 0.03 mm), fifth (0.94 ± 0..04 mm) instar larva, and width with wing expanded in female adult (17.83 ± 0.40 mm) were significantly bigger in the culture reared on flowers compared to the culture reared on leaves. The growth index in the culture reared on flowers (6.86) was high than in the culture reared on leaves (5.56). The period of third instar (1.60 ± 0.49 days), fourth instar (2.67 ± 0.79 days) and, fifth instar (3.33 ± 0.47 days); total larval period (10.13 ± 1.02 days); total life cycle in male and female (21.17 ± 1.77 days and 23.67 ±2.00 days, respectively) were significantly shorter in the culture reared on flowers as compared to the culture reared on leaves. Two cultures did not differ significantly in respect of biometrics and period of rest of the stages. The hatching percentage (78.01 ± 2.71) was also significantly higher in the culture reared on flowers than that on leaves (72.44 ± 1.88), but two culture did not differ in fecundity. Fourth and fifth instar larvae were cannibalistic and fed on earlier instars. Larva significantly preferred to pupate in leaves followed by capsules and flowers. The flowers were preferred most for oviposition. Females had a preponderance over males in laboratory as well as in field condition. The average per cent parasitism to the larvae of A. catalaunalis by Diadegma sp. (Ichneumonidae : Hymenoptera) was 21.62 and 19.59, respectively during 2000 and 2001. Phenerotoma sp. (Braconidae : Hymenoptera) caused on an average 7.34 per cent parasitism in the year 2001. The average per cent parasitism by both the parasitoids was 29.61 during the year 2001. The egg and larval population in sesamum crop was found at higher level during September. The greater difference in the maximum and minimum temperature(hotter days and cooler nights) i.e., 8 to 14°C(X17) longer sunshine hours i.e.,1 to 8 hrs (X1), low wind speed i.e.,3 to 4 km/hrs (X14) and no rainfall were found to be congenial conditions for the development of higher population of pest in sesamum crop. The relationship between population (Y) and meteorological parameters (X) in the form of regression equation with coefficient of determination (R2) given in bracket was : Y = 0.4650 + 0.0635 X17 (R^:0.5960) for the eggs and Y = 0.8688 + 0.0352X1 - 0.0445 X14 (R2:0.54) for the larvae. The sesamum genotypes, AT-80 and AT-78, recorded less than 10 percent flower damage and 5 percent capsule damage under Large scale varietal trial were found less susceptible to the larvae. Among synthetic insecticides, Spark 36EC a ready-mix insecticide (deltamethrin 1% + triazophos 35%) used @ 0.036%, while among botanical/neem based formulations, neem seed kernel extract used @ 5% suspension were found most effective treatments for the control of infestation by the larvae in sesamum crop.
Description
Keywords
AGRICULTURAL ENTOMOLOGY, AGRICULTURE, A STUDY