DETERMINATION OF THE CRITICAL PERIOD OF COMPETITION OF WEEDS IN COWPEA BEAN Vigna unguiculata (Walp) IN ALANJE, PANAMA, 1989.

Abstract

The effect of competition of weed on the yield of the cowpea Vigna unguiculata (L.) Walp, was studied. The growth of thicket during the entire cycle of cultivation, approximately 75 days, caused a reduction in yield of 75%, compared to the yield obtained when cultivation is maintained free of competition throughout the whole cycle. Growth of weed during the first 40 days of cultivation caused a reduction in yield of 59%. The parcels where competition was only allowed during the first 10 days and those maintained without competition during the first 40 days suffered a reduction in yield of 6 and 22%, respectively. The reductions in yield become significant at 6%. It is concluded that the critical period of competition of weed lies between the first 10 and up to 40 days of emergence of the cowpea plants.