Simaroubaceae and Picramniaceae as potential sources of botanical pesticides

Prospection for new sources of botanical pesticides has shown a revival in the last decades due not only to the fast development of resistance among different pests around the world but also by the need to use less eco-toxic products to control etiological agents of different pest-related problems found in agro-production. In this work, extracts from members of the families Simaroubaceae (Ailanthus altissima, Castela coccinea and Picrasma crenata) and Picramniaceae (Alvaradoa subovata and Picramnia sellowii) were evaluated for their toxicity against the cattle tick and for their antifeedant activity against insects. At the tested doses, none of the extracts exhibited a good toxicity against larvae of the common cattle tick. On the other hand, antifeedant activity was detected in various extracts. Foliage consumption was completely deterred in adults of the specialist Epilachna paenulata in the cases of the C. coccinea leaf and wood extracts and P. crenata wood extract. For larvae of the generalist Spodoptera frugiperda antifeedant effects were also detected, although in a lesser extent. Phytochemical analyses of the extracts showed the presence of alkaloids in P. crenata (including canthin-6-one) and in C. coccinea. Besides, GC/MS analyses of the wood extract from C. coccinea showed the presence of several steroids (ergot 5-en-3-ol-acetate, stigmastan-3,5 diene and stigmasta-3,5dien-7-one). Anthraquinones (emodin and chrysophanol) as well as chlorogenic acid were detected in the cases of A. subovata and P. sellowii extracts. The differences in deterrent activity could not be atributed to differences in the HPLC chemical profiles of the different extracts. (C) 2012 Elsevier B.V. All rights reserved.