EFFECT OF TRAP COLOR ON SPECIES COMPOSITION OF ALATE APHIDS (HOMOPTERA-APHIDIDAE) CAUGHT OVER WATERMELON PLANTS

The species composition and abundance of alate aphids caught in water traps containing green or yellow tiles were compared. Traps were opera ted in a watermelon field during the spring and autumn growing seasons of 1992. Aphis spiraecola Patch, a vector of watermelon mosaic virus 2 (WMV-B), accounted for 79% of the aphids caught in the spring and 91 % of those caught in the autumn in yellow traps. However, this species accounted for only 6% and 11% of aphids caught in green traps in the spring and autumn, respectively. Uroleucon pseudambrosiae (Olive), als o a vector of WMV-2, was the most abundant aphid in green traps in the spring but was absent in the autumn. Aphis gossypii Clover (16% of ap hids in green traps) and Aphis craccivora Koch (31%) were more common in the autumn than in the spring and may be important vectors of cucur bit potyviruses at that time.