Nutritional Responses of the Black Cutworm, Agrotis ipsilon (Hufn.), Larvae under Toxicity Effects of Five Wild Botanical Extracts from Sinai, Egypt

Abstract

Aims: To identify the chemical components of five wild Botanical oils (BOs) and their larvicidal influences on the anti-nutritional indices of the 4th instar larvae of Agrotis ipsilon.
 Study Design: A comparative study with the randomized design, using five plant Extracts replicated five times.
 Place and Duration of Study: Mentha longifolia, Artemisia judaica, Majorana hortensis, Origanum syriacum, and Achillea santolina were collected from the Sinai desert, Egypt. Study procedures were done at the Laboratory of Botany and Zoology, Faculty of Science, Zagazig University, Egypt, between December 2018 and June 2020.
 Methodology: An analysis of the tested BOs components was done using a Shimadzu GC-9A gas chromatograph. Five sub-lethal concentrations of each plant were prepared (5 replicate/treatment) to evaluate medium lethality against A. ipsilon larvae (20 larvae/replicate). Untreated larvae were used distilled water only as a control. Ten larvae of each treatment were treated with only one LC50 to estimate the effect of different tested BOs on anti-nutritional Activities.
 Results: The main component of the M. longifolia and A. judaica oil was Piperitone at 39.79 and 37.55%, respectively; whereas the M. hortensis, O. syriacum, and A. santolina oil was Terpinen-4-ol, Thymol, and Fragranyl acetate at 29.82, 31.21, and 25.67%, respectively. According to LC50 of the tested BOs, the toxicity of A. judaica, M. longifolia, O. syriacum, respectively, were the most effective oils, while M. hortensis and A. santolina oils were the least susceptibilities. The more toxic oils reduced food consumption, causing a significant decrease in relative consumption rate (RCR), growth rate (RGR), and efficiency of conversion of ingested food (ECI)/digested (ECD). The previous oils also showed a significant increase in metabolic cost (MC) and anti-feeding activities against A. ipsilon larvae compared to M. hortensis and A. santolina.
 Conclusion: It is suggested that A. judaica and M. longifolia extracts contain high Piperitone content and could be accepted as toxicants to control A. ipsilon.