Aphids capable of fine resolution landing

Aphids vector many devastating plant viruses, including the non-persistent papaya ringspot virus (PRSV), which reduces yield in both cucurbits and papaya. It has been demonstrated that some aphids are more attracted to colors symptomatic of virus infection, especially yellow. However, alate aphids are small and presumably weak fliers carried along primarily by the wind. We used clear sticky traps on squash foliage and papaya foliage that either displayed chlorotic symptoms typical of PRSV or were healthy. Very few aphids were trapped on the clear traps, even though yellow traps above these fields indicated large populations of alate aphids. We placed yellow traps at seven different heights above the squash planting (from 0.1 to 1 m). In addition, we placed clear plastic traps in an identical array and an array of mixed yellow and clear traps. Our study demonstrated consistent patterns. Yellow traps caught many more aphids than clear traps. Aphid capture on yellow traps was positively correlated to height for the heights assayed and aphids were able to land on yellow traps that were immediately adjacent to clear sticky traps (clear sticky traps immediately adjacent to yellow traps had few or no aphids) demonstrating a capacity for fine resolution landing (on the order of cms). The results are discussed as they pertain to disease transmission by aphids.