Importance of Nettle on Crop Protection

Organic farming has an important place in agricultural economy. However few studies talk about biological control of many enemies groups. This study aims to illustrate nettle efficiency as preventive fight towards both insect’s outbreaks and disease infestation. It consists of verifying if nettle extract has curative properties towards gummosis citrus or stops development disease and we evaluated its efficiency on main insects’ pests of bean. Moreover nettle field of insects was tested if it can protect bean. Investigational device was realized during season crop 2017-2019 and took place in market gardens around the city Antananarivo (Madagascar). Nettle field of insects’ efficiency was compared with witness plots and field of insects which composed with various companions’ plants (maize, nettle, crucifers). Each companions’ specie grows on 1 m width and the length depends on plot size which needs protection. And nettle extract modalities were compared with witness untreated and reference treatment such as garlic extract for insecticides plants and Bordeaux mixture for mineral fungicide. Each bean plot has a surface of 20 m2 spaced out at least 0.5 cm. Three repetitions were realized for each modality. For citrus disease evaluation was realized on 10 observed plants that each plant constitutes one modality. Evolution of pest number for bean and symptoms of gummosis (yellow leaf importance and phytosanitary situation after treatment) was observed as parameters. As results, nettle extract has a better efficiency to control bean aphids as reference treatment and restores citrus gumminess as much as treated with mineral fungicide. Similarly, nettle field of insects presented the same efficiency to allow diversifying pest as diversification field insects’. In sum use of nettle extract needs tracking on gummosis citrus if there was reverse disease. Nevertheless, nettle has appreciable protection properties on crops which can help farmers to produce in a sustainable and environmentally-friendly way.