| Carica papaya L. is severely affected by the papaya ringspot virus (PRV), that affects the plant and the fruit. Various species of aphids are vectors of the PRV, although none of the species colonize the plant. Trials were conducted at the Agricultural Experimental Station of the University of Puerto Rico at Isabela and Corozal to evaluate the effect of reflective plastic mulch, black plastic mulch, green cover crop (weeds and Wedelia trilobata) and bare ground on the incidence of the PRV and alate aphids. In both experiments the P.R. 6--65 variety was used in a completely randomized design with 5 repetitions. The presence of symptoms of the PRV was determined visually every 15 days. The relative abundance of aphids was determined weekly.;The species of aphids identified were: Toxoptera citricida (Kirkardy), Toxoptera aurantii (Boyer de Fonscolombe), Pentalonia nigronervosa Coquerel, Tetraneura nigriabdominalis (Sasaki), Uroleucon ambrosiae (Thomas), Aphis spiraecola Patch, Aphis gossypii Glover, Aphis craccivora Koch, Aphis illinoisensis Shimer and Picturaphis sp. Blanchard. In Isabela, the use of plastic mulch (reflective and black) reduced aphid population density and delayed the appearance of PRV. In both localities, the best yields were related to the use of plastic mulch. The cover crop, W. trilobata, did not affect aphid density. Aphid relative density increased with the presence of weeds. It is concluded that utilization of plastic mulch is an effective practice against the PRV and aphids in papaya. |
