Toxicity and antifeedant activity of Caesalpinia bonduc (L.) Roxb. (Caesalpiniaceae) extracts and fractions against the cotton bollworm Helicoverpa armigera Hub. (Lepidoptera: Noctuidae)

Natural pesticides show a number of advantages if compared to synthetic pesticides, since they are cheap, biodegradable, and minimal harmful to humans and animals, livestock and wildlife. Furthermore, natural biopesticides are easily accessible by poor marginalized rural populations in developing countries. Here, crude extracts and fractions of Caesalpinia bonduc (L.) Roxb. (Caesalpiniaceae) were evaluated for their biotoxicity against the cotton bollworm, Helicoverpa armigera Hub. (Lepidoptera: Noctuidae). Maximum antifeedant, larvicidal and pupicidal activities were observed testing the chloroform extract of C. bonduc. Therefore, C. bonduc chloroform extract was fractionated using solvents of increasing polarity. Based on the TLC profiles, six fractions were isolated. All fractions were tested against H. armigera. Maximum antifeedant, larvicidal, pupicidal activities, as well as the highest treatment impact on larval-pupal duration were recorded testing fraction 3. Overall, the present study allowed us to consider the cheap and easy to obtain fraction 3 as a promising source of botanical products effective in the fight against agricultural pests, with special reference to the cotton bollworm, in an eco-friendly perspective.