Monitoring the evolution of crop pests: tomatoes and onions

Market gardening in the Alaotra Mangoro region is carried out in the off-season. However, due to the effects of climate change, rainy season tomato and onion growing practices are becoming increasingly productive and constitute a considerable source of income for farmers. As these wet season practices are new to Alaotra, monitoring of pest trends following climate change is necessary to assess their economic impact. Several techniques are used to collect and inventory pests according to their phenological stage. On tomato crops, Spodoptera littoralis, Heliothis armigera, Pardalaspis cyanenscens, and Tetranychus neocaledonicus are the most devastating. On the other hand, on the onion crop, the majority of the damages are associated with Heliothis armigera, Spodoptera littoralis, Plusia sp, and Liriomiza trifolii. Concerning diseases, fungal diseases were the most important.