Botanical fungicide for sustainable production of fresh vegetables

Pests and diseases are a major challenge to vegetable production. Growers rely on chemical pesticides for management but despite their efficacy, synthetic pesticides have negative effects on the applicator, consumers and environment. Some of the chemical pesticides are highly toxic to humans and non-targeted organisms, and their compounds are often non-biodegradable and therefore accumulate in the environment resulting to pollution and loss of biodiversity. Therefore, there is need for safe but efficacious alternatives to chemicals in integrated pest management. Compounds of plant origin have been found safe and have been commercialized mainly for the management of insect pests. This study aims at developing a botanical fungicide from rhizomes of turmeric and ginger for the management of a range of fungal plant pathogens. Turmeric (Curcuma longa) and ginger (Zingiber officinale) rhizomes collected from farmers will be ground and extracted in alcohol. The extracts will be tested for efficacy against fungal plant pathogens in vitro. The mode of action of the active compounds on fungal spore germination, cellular structures, germ tube and hyphal growth will be determined by microscopy. The phytochemical composition of the active extracts will be analysed by high performance liquid chromatography (HPLC). The most active extract will be formulated using locally available carriers and evaluated for efficacy against fungal plant diseases under farm field conditions. It is envisaged that a broad spectrum botanical fungicide will be identified and this would contribute to effective management of fungal diseases in vegetables and reduce the usage of synthetic pesticides, thus positively impacting on human health, environment and trade.