A new major parasitic plant in rice in Togo: Rhamphicarpa fistulosa

Abstract

A new major parasitic plant in rice in Togo: Rhamphicarpa fistulosa Rhamphicarpa fistulosa (Hochst.) Benth. (Scrophulariaceae) is an annual facultative rootparasitic weed found in the lowlands and floodplains of tropical Africa. It has been reported to be the major biotic constraint to rice cultivation in the Savannah region of Togo. A survey was conducted in 2012 to determine its geographical spread and to collect information on farmers' knowledge of its control. An investigation based on semi-open questions was carried out among the people visited. Rhamphicarpa fistulosa was found in 80% of the 33 lowlands visited. The period of abundance is in August-September with the highest infestation (90%) being found on sandy and clay soils. When the parasite was present, 94 other weeds belonging to 24 botanical families were recorded. As a method for parasite control, farmers use hand weeding and apply chemical fertilizers but always at lower input rates than national standards. Heavy infestation levels lead to the abandonment of plots while other reported types of damage provoke growth reduction of rice plants and plant yellowing.