摘要
The sweetpotato production in Tanzania has been increasing due to the changing status of the crop from famine relief to a commercial crop particularly in the central zone of Tanzania.Production of the crop is affected by environmental and biotic stresses.Apart from prolonged drought which affects timely availability of planting materials,sweetpotato weevils were recently reported by growers as a major setback to the productivity of the crop.The study was conducted between December 2016 and July 2017 in Gairo and Ikungi Districts of Morogoro and Singida regions respectively.The aim was to identify sweetpotato weevil species existing in the area,determine the seasonal abundance of the pests and test the response of popular and farmers’preferred sweetpotato varieties to the pest.The effect of planting time on the abundance of sweetpotato weevils was also studied.It was established that Cylas puncticollis is the lone weevil species infesting the crop in the study area.Time of planting significantly(p<0.05)influenced weevils’abundance with early planted crop sustaining least number of pests compared to the late planted.Sweetpotato variety,Gudugudu was least damaged by C.puncticollis.Locational influence suggested that Gairo District sustained greater weevil abundance and associated damages compared to Ikungi District.It was concluded that planting dates had influence on seasonal abundance of sweetpotato weevil with early planted crop sustaining least infestation with C.puncticollis compared to late planted crop.
