Field Efficacy of a Biopesticide Based on Tithonia diversifolia against Black Sigatoka Disease of Plantain ( Musa spp., AAB)

Abstract

Black Sigatoka disease (BSD) is a foliar disease caused by Mycosphaerella fijiensis, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influence on fruit physiology. The control of BSD relies on the use of chemicals which are not affordable for the small holder farmers and increase the cost of production. Moreover, this chemical control is ineffective, negatively impacting the environment and human health, and is at the origin of strain resistance. Tithonia diversifolia is known as rich in many compounds such as mineral elements, defense metabolites, some phytochemicals; and it is increasingly used in agriculture. Recently, the protective effect of Tithonia diversifolia liquid extract against BSD development on plantain vivoplants in the nursery was highlighted. The aim of our study was to evaluate the efficacy of a biopesticide base on Tithonia diversifolia on the BSD development in a plantain field under high disease pressure. The effect of Tithonia diversifolia biopesticide on Mycosphaerella fijiensis mycelial growth in vitro was evaluated. An experimental field at the flowering stage was selected and treated with the biopesticide base on Tithonia diversifolia at three different concentrations: undiluted (100%), diluted at 1/2 (50%) and diluted at 1/4 (25%) for 17 weeks. The disease severity, the number of functional leaves, the youngest spotted leaf (YSL) and the youngest necrotic leaf (YNL) were evaluated in course of time. The biopesticide treatments significantly (P Tithonia diversifolia could be a hopeful ecoresponsible solution for the plantain sector in general and in particular for poor small farmers.