Contact toxicity of Essential Oils from Tithonia diversifolia against Aphis gosypii, Thrips tabaci and Bemisia tabaci

Abstract

Plants and microbes provide naturally occurring chemicals that are often used for the control of pests all around the world. Biopesticides have been used as a comparatively safer replacement for synthetic pesticides for the past five decades. This study determined the contact toxicity of essential oils from the Tithonia diversifolia plant against Thrips tabaci, Bemisia tabaci, and Aphis gosypii. The essential oils (Eos) were extracted from dry leaves by hydrodistillation using the Clavenger apparatus for 8 hours. GC-MS was utilised to analyse the qualitative and quantitative composition of essential oils, whereas ATR-FTIR was employed to determine the functional groups. 3-Carene was the most abundant compound ion in the Eos. T. tabaci, B. tabaci, and A. gosypii were used in the bioassay of the crude extracts. T. tabaci, B. tabaci, and A. gosypii were tested for contact toxicity against mixed-sex adult pests. Five distinct concentrations were made, each of which was repeated five times. Permethrin, a commercial chemical pesticide was utilised as a positive control and acetone were used as a negative control. The essential oils’ LD50 was calculated using SPSS version 26.0 Probit analysis. After 24 hours, the pests’ response to the treatments was assessed using a blunt instrument probe, and those that did not respond were counted as dead. Essential oils from T. diversifolia had the lowest LD50 against T. tabaci, with a value of 0.085 µL. This suggests that T. diversifolia could be employed as a T. tabaci contact toxicant. (P < 0.05, α = 0.05) The outcomes were statistically significant. As a result, essential oils from T. diversifolia can be employed as a biopesticide against T. tabaci as a contact toxicant.