A Review on: common botanicals in Nepal on management of crop diseases

Abstract

The crop production is turn down by many pathogens, weeds, insects comprising 36.5% of annual loss under field and 14% during storage conditions. Among many practices adopted to manage plant diseases, use of synthetic chemicals is more convinced and are adopting as a last resort of the disease management worldwide. Despite of its efficacy, use of chemicals is threatening the environments, health of human and animals because of its residual toxicity, non- specificity, resurgence and costly nature. Emerging agriculture is now being replacing the hazardous chemicals through the use of biological and botanicals. The botanicals growing naturally possess numerous antimicrobial metabolites that act against various pathogens reducing the disease severity with out having adversities on animal health and environment. Neem, Melia, Datura, garlic, ginger, turmeric, eucalyptus, onion, basil, tobacco, nettle, black pepper, chilli etc. have antimicrobial metabolites such as phenols, phenolic acids, quinones, flavones, flavonoids, flavanols, tannins, coumarins etc. These constituents can be potential pesticides. From in-vivo and in-vitro studies on their effectiveness it has been proved that they can be the best substitutes for synthetic chemicals in agriculture. Among the plant species in world, only 10% of the plant species have been reported to have pesticidal activities. Identification of such plant species and production of plant-based formulation is most essence for economic and eco-friendly management of plant diseases. Therefore, having a better understanding of these alternative pesticides could be beneficial for engaging in sustainable agriculture, especially given that they are less dangerous, practical from an economic standpoint, simple to use and capable of managing pests and pathogens in both fields and stores (postharvest). The review is subjected to study the efficacy of botanical extracts for the management of crop diseases as a better alternative to the chemicals and it summarizes the findings from previous researches