Population Fluctuation of Bihar Hairy Caterpillar, Spilarctia obliqua (Walker) and its Natural Enemies on Castor Under Semi-arid Conditions of Gujarat

Manuscript ID: IJECOL-26-0134
Published in: Volume 53, Issue 2 (2026)
Article Type: Research Article
DOI: https://doi.org/10.55362/IJECOL/2026/0134

Authors & Affiliations

Dhruvkumar N Parmar
Department of Entomology, College of Agriculture, Junagadh Agricultural University, Junagadh-362 001, India
ORCID: 0009-0000-3317-4152
M K Chandaragi Corresponding Author
Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar
ORCID: 0000-0003-1697-0020
Email: mallu3731@gmail.com
Sai Thilak Koosi
Navsari Agricultural University, Navsari
ORCID: 0009-0004-4463-8118

Article Dates

RECEIVED April 17, 2026
REVISED June 03, 2026
ACCEPTED June 08, 2026
AVAILABLE ONLINE June 17, 2026

Abstract

Bihar hairy caterpillar, Spilarctia obliqua (Walker), is a polyphagous lepidopteran pest, known to cause substantial damage to a wide range of agricultural and horticultural crops. In recent years, its occurrences have become increasingly severe in castor, Ricinus communis L. cultivation in Western India. Therefore, to study the seasonal incidence and damage potential dynamics study was undertaken on castor (GCH-8) during Kharif, 2024-25 at Centre for Oilseeds Research, S. D. Agricultural University, Sardarkrushinagar. The results revealed that peak larval incidence (43.52 larvae/plant) was observed during the 45th SMW, coinciding with maximum foliar damage (58.44%) during 44th SMW. The larval parasitoid, Cotesia ruidus (Wilkinson) was recorded from natural field infestations in castor. The highest population (1.60 spiders/plant) of spider (adult and spiderling) was recorded at 49th SMW and maximum (1.00 coccinellids/plant) coccinellids (adults) during 44th SMW and maximum population of Chrysoperla (1.40 Chrysoperla/plant) during 44th SMW. Multiple regression analysis revealed that abiotic factors had a strong influence on pest incidence, particularly larval population (R² = 0.66) and leaf damage (R² = 0.61). while, natural enemies showed weaker to moderate relationships (R² = 0.18–0.45) which indicated a greater role of abiotic factors

Keywords

Spilarctia obliqua, castor, population dynamics, parasitoid, natural enemies, regression

Classifications

Agroecology Crop environment interaction

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Cite As

Parmar, D. N., Chandaragi, M. K., & Koosi, S. T. (2026). Population fluctuation of bihar hairy caterpillar, spilarctia obliqua (Walker) and its natural enemies on castor under semi-arid conditions of gujarat. Indian Journal of Ecology, 53(2), 421-428. https://doi.org/10.55362/IJECOL/2026/0134

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