Farmers' perceptions of cassava pests and indigenous control methods in Cameroon

Abstract

A survey of farmers' views on cassava pests was conducted in 61 locations in four cassava-producing agro-ecological zones in Cameroon. Farmers in all zones considered vertebrates, grasshoppers and cassava root rot as their most important pest and disease constraints. Weeds, although cited in all zones, received relatively low ratings. Damage caused by the cassava green mite (CGM) [Mononychellus tanajoa Bondar (Acari: Tetranychidae)], was recognized but its cause was unknown. The cassava root scale [(Stictococcus vayssierei Richard (Homoptera: Stictococcidae)] was important only in the semi-humid forest zone. Farmers control pests using cultural methods including trapping, scaring, poisoning and burning for vertebrates, hand picking for grasshoppers, and burning, hand weeding and long fallows for weeds. In most cases, root rot occurred after cassava reached maturity, and farmers recognized the importance of timely harvesting to control crop losses. Cassava diseases such as cassava mosaic disease (CMD), cassava anthracnose disease (CAD), and cassava bacterial blight (CBB), although recognized, were not considered as serious constraints. However, entomologists and the other researchers found CGM to be the most important arthropod pest overall, causing serious damage to cassava. Damage due to vertebrates was also found but not to the extent that farmers reported. It was apparent that farmers considered highly visible pests such as vertebrates and grasshoppers more important than less visible ones such as CGM. The need to educate farmers about small arthropod pests and their damage/importance was clear. Therefore IPM programmes aimed at cassava pests should involve consideration both of the importance farmers attach to each pest and of the education farmers receive concerning the prevailing pest situation.