Abstract
Populations of beetles were measured at weekly intervals on plants of Los Banos Bush Sitao, a dwarf cultivar of vegetable cowpea (Vigna unguiculata (L.) Walp.). Observations were made on crops grown in the dry and rainy seasons of Trinidad. Four chrysomelid vectors of cowpea severe mosaic virus (CPSMV) were observed, namely Cerotoma arcuata (Oliv.), C. ruficomis (Oliv.), Gynandrobrotica equestris (Fab.) and Systena s-littera (L.). In both seasons, C. arcuata was the only species consistently found at the earliest sampling dates (primary leaf stage) and was also observed throughout the crop at population levels 5-20 times those of the other three species. Its population dynamics were closely related to the growth of the crop but there were indications that its life cycle differed in the dry and rainy seasons. Based on its population dynamics and high population levels, C. arcuata was characterized as the major field vector of CPSMV in Trinidad.
