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Indian Journal of Entomology
Year : 2020, Volume : 82, Issue : 3
First page : ( 532) Last page : ( 536)
Print ISSN : 0367-8288. Online ISSN : 0974-8172.
Article DOI : 10.5958/0974-8172.2020.00133.9

Efficacy of Phlogocanthus thyrsiflorus against Oligonychus coffeae and Helopeltis theivora in Tea

Borbaruah Priyanka*, Kalita Surajit1

Department of Entomology, Assam Agricultural University, Jorhat, 785013, Assam

1Directorate of Research (Agri), Assam Agricultural University, Jorhat, 785013, Assam

*Email: priyankaborbaruah1@gmail.com (corresponding author)

Online published on 24 September, 2020.

Abstract

Laboratory experiments were conducted at the Department of Entomology, Assam Agricultural University, Jorhat during 2016–18 to evaluate the efficacy of solvent extracts of Phlogocanthus thyrsiflorus against Oligonychus coffeae Nietner and Helopeltis theivora Waterhouse attacking tea. The extracts were compared with neem seed kernel extract 0.15%, fenpyroximate 5EC (for O. coffeae) and deltamethrin 2.8EC (for H. theivora). The methanolic extract exhibited a strong acaricidal property with 100% adult mortality of O. coffeae at 48 hr after treatment (HAT), while the petroleum ether and water extracts led to 98.33% and 55.00% mortality, respectively. The methanolic extract led to only 26.67% mortality with H. theivora adults at 10.0% concentration after 48 HAT. The methanolic leaf extract against O. coffeae was thus comparable with fenpyroximate 5 EC @ 1ml/l at 48 HAT with 100% adult mortality. The order of toxicity in terms of LC50 values of leaf extract of P. thyrsiflorus against O. coffeae was: methanol (0.531%) >petroleum ether (0.602%) >water (7.692%); as against methanol (28.348%) >petroleum ether (35.560%) >water (38.873%) in case of H. theivora.

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Keywords

Tea, Phlogocanthus thyrsiflorus, Leaf extracts, Methonolic extract, Oligonychus coffeaeHelopeltis theivora, Mortality, LC50, Acaricide, Toxicity.

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