Abstract
Sweetpotato [Ipomoea batatas (L.)] germplasm was evaluated and used to determine the contribution of cultural practices including mulching and irrigation on yield of sweetpotato and the reduction of sweetpotato weevil (SPW), Cylas formicarius elegantulus (Summers) infestation, the most economically devastating pest of sweetpotato in the United States Virgin Islands (USVI). The germplasm evaluation trials were conducted using cultivars obtained from the U.S.A., Puerto Rico (USDA-TARS), St Kitts, and the USVI. Results indicated a high per cent SPW infestation on storage roots of high-yielding cultivars, but local cultivars produced lower yields than introduced cultivars. Most cultivars from Puerto Rico were very well adapted for production in the USVI. Mulching generally increased the yield of cultivar Sunny, with the plastic mulch producing the highest yield of medium-sized roots while grass mulch reduced SPW infestation of storage roots. Irrigation significantly increased marketable yields of storage roots compared to the rainfed treatment. Additionally, irrigation maintained at 40 kPa produced the highest yield of medium-sized storage roots which was significantly higher than the 20 kPa and rain-fed treatments. These studies indicate that for improved sweetpotato production in the USVI, growers should consider the use of locally adapted cultivars, mulching, and an optimum irrigation level.
