Efficacy of Citrullus colocynthis seed extract on Earias vittella, Fabricius, (Lepidoptera: Noctuidae): environment sustainable approach

Abstract

Earias vittella Fabricius, 1794 (Noctuidae: Lepidoptera) is deliberated to be one of the most destructive pests of cotton and okra vegetation in the world including Asia. The pest has established resistance to various synthetic insecticides. The use of bio-pesticide is one of the unconventional approaches to develop a vigorous ecosystem without harming non- target pests and beneficial natural insect fauna. In the present study, the toxicity levels of Citrullus colocynthis seed extract have been evaluated against the populations of E. vittella under standardized laboratory conditions. The toxic effects of C. colocynthis on development periods, protein contents and esterase activity of the life stages of E. vittella were also evaluated. The toxicity levels of methanol, ethanol, hexane, water and profenofos were evaluated on the 1st instar larvae of E. vittella. LC₃₀ and LC₈₀ concentrations exhibited the effectiveness of methanol-based C. colocynthis seed extract against 1st instar larvae of E. vitella. The enhanced larval and pupal periods were revealed in treated samples during the comparison with untreated samples. The intrinsic rate of increase, net reproductive rate in the LC₃₀ and LC₈₀ concentrations exposed larvae remained less than the control treatment. Fecundity, the esterase activity and protein contents were declined in LC₃₀ and LC₈₀ treated samples as compared to the control. The present findings suggest that C. colosynthis extracts based botanical insecticides are beneficial, ecosystem sustainable and can be integrated with insect management programs from environment safety perspective.

Alternate abstract:

Earias vittella Fabricius, 1794 (Noctuidae: Lepidoptera) é considerada uma das pragas mais destrutivas de algodäo e quiabo no mundo, incluindo a Ásia. Essa praga estabeleceu resistencia a varios inseticidas sintéticos. O uso de biopesticidas é uma das abordagens näo convencionais para desenvolver um ecossistema saudável sem prejudicar as pragas näo alvo e a fauna natural benéfica de insetos. No presente estudo, os níveis de toxicidade do extrato de semente de Citrullus colocynthis foram avaliados nas populaçoes de E. vittella em condiçoes de laboratorio padronizadas. Os efeitos tóxicos de C. colocynthis nos períodos de desenvolvimento, conteúdo de proteína e atividade esterase das fases de vida de E. vittella também foram avaliados. Os níveis de toxicidade de metanol, etanol, hexano, agua e profenofós foram avaliados em larvas de 1° instar de E. vittella. As concentrares de LC₃₀ e LC₈₀ apresentaram eficacia do extrato de sementes de C. colocynthis a base de metanol contra larvas de 1° instar de E. vittella. Os períodos larval e pupal aumentados foram revelados nas amostras tratadas durante a comparaçâo com as amostras näo tratadas. A taxa intrínseca de aumento e a taxa reprodutiva líquida nas concentraçoes de larvas expostas LC₃₀ e LC₈₀ permaneceram menores do que o tratamento controle. A fecundidade, a atividade da esterase e o conteúdo de proteína diminuíram nas amostras tratadas com LC₃₀ e LC₈₀ em comparaçâo com o controle. As presentes descobertas sugerem que os extratos de C. colocynthis a base de inseticidas botánicos säo benéficos, sustentáveis para o ecossistema e podem ser integrados com programas de manejo de insetos do ponto de vista da segurança ambiental.