Yam-based farm practices and nematode problems in stored yams (Dioscorea spp.) in Ghana

A survey was made to provide fundamental information on yam-based farm practices, nematode problems and to establish farmers' perceptions of nematode diseases in stored yam tubers in Ghana. Most farmers intercropped yam with a mixture of three to five component crops and milking was practised to provide seed yams. Results showed that farmers could readily identify symptoms of nematode disease and estimated losses from dry rot disease to be about 21% in the forest zone and, 30% in the Guinea- Savannah zone. Even though farmers reported tuber galling in the forest transition, they estimated losses from root knot nematodes to be zero in the Guinea-Savannah. Most farmers had local names for nematode disease and this tends to suggest that farmers perceive nematode disease problem. They used cultural control methods such as selection of clean yam tubers, fallow and use of land not previously cropped to yam to reduce nematode disease spread. Scutellonema bradys was found to be associated with dry rot whilst Meloidogyne incognita was found to cause galling of yam tubers. Pratylenchus coffeae is known to be widespread in Ghana on Musa spp. but it was not encountered in our study. Different yam storage structures were used by farmers and tubers were apparently exposed to conditions that promoted damage by nematodes. Journal of Science and Technology Vol. 25(2) 2005: 35-43