In Niger, moringa leaf production keeps market gardeners busy in most urban and peri-urban areas. The economic importance of moringa is well established, given the area planted, its virtues and its contribution to nutritional security and poverty reduction. However, in recent years, moringa productivity has fallen considerably due to the almost constant pressure of defoliating insects. Faced with this situation, growers are using unregistered chemicals of dubious origin, often hazardous to human health and the environment. This study aims to find alternative methods to chemical control, in particular by promoting agroecological management. The study was conducted in a Fisher block design with four (4) replications and four (4) treatments, where the potential of basil, sorghum and maize in the management of moringa defoliating insects was tested. Insect abundances and diversity indices were calculated and compared between treatments. Defoliation levels were determined by treatment. Analysis of the results showed that basil and sorghum reduced insect abundance by 7% and 5% respectively, and increased insect diversity by 8% and 13% respectively with the presence of natural enemies in the plots. Similarly, the results revealed the potential of basil and sorghum to very significantly (Pr = 0.0015) reduce defoliation by 36% and 34% respectively in moringa plots. Sorghum and basil may be better candidates for inclusion in the agroecological management of moringa defoliating insects.
The fall armyworm (Spodoptera frugiperda J.E. Smith), was first reported in sub-Saharan Africa in January 2016 in Nigeria, Sao Tome, Benin and Togo. Shortly after its introduction, its presence was confirmed in more than thirty countries on the African continent. This rapid spread associated with its polyphagy and voracity confirms its status as a major pest that feeds on the leaves and stems of over eighty (80) plant species. This situation constitutes a serious threat to African agriculture and more precisely to the food and nutritional security of the populations of the affected countries. The major hosts of Spodoptera frugiperda are maize (Zea mays), sugarcane (Saccharium officinarum), and sorghum (Sorghum bicolor) and rice (Oriza sativa). Studies reveal that damage by this moth is most severe on maize where all parts of the plant are attacked causing yield losses ranging from 15 to 73% when 55 to 100% of the plants were attacked. This review provides an update on research on Spodoptera frugiperda in Africa with particular emphasis on its bioecology, host plants, economic importance and different methods of infestation management. Significant research work has been carried out in Africa since the detection and expansion of CLA in Africa. The analysis of the results of this work attests to a better knowledge of this lepidopter an, which has allowed the design of several management strategies for CLA. Among these strategies, agroecological management, the push-pull approach, the use of pheromone traps and resistant varieties, chemical control with Dimethoate and Deltametrine and biological control with parasitoids, in particular Telenomus sp, Trichogramma sp for ovoparasitoids and Cotesia icipe for larval parasitoids, have been widely tested.