Bibliography

Questionnaires and sampling techniques were developed to assess the distribution, problems caused by, and the efficacy of control methods for Imperata cylindrica (L.) Raeuschel. One hundred farmers were interviewed from each of the three agro-ecological zones of Benin. These differ in climate, especially annual rainfall, and in crops cultivated. I. cylindrica was the most serious weed in the high and medium rainfall zones but was less prevalent in the arid zone. In all zones, the recent intensification of agricultural land use caused a reduction in the use of fallow and cover crops, resulting in increased incidence and severity of I. cylindrica. Significant yield losses due to I. cylindrica infestation were reported for all crops, including cassava, cotton, cowpea, maize, millet, peanut, sorghum, and yam. Furthermore, the clearance of vegetation by “slash and burn” agriculture encouraged rapid leaf growth from rhizomes to create dense stands of I. cylindrica that virtually eliminated other species. Such areas were frequently abandoned because existing control methods were ineffective. Weeding by hand caused cuts due to sharp leaf margins and leaf tips occasionally caused injury leading to blindness. Frequent ploughing can break rhizome sections into pieces sufficiently small to avoid plant regeneration, but was considered too time and labour intensive. Of the 300 farmers surveyed, none used chemical herbicides, due to high cost. This study showed the need to develop sustainable methods of I. cylindrica control for resource poor farmers.