2019 ASHS Annual Conference

Although the central Kentucky climate and growing conditions lend themselves to high quality summer squash (Cucurbita pepo L.) production, there are several prominent pests that can lead to significant yield losses. One pest Kentucky growers are concerned with is aphids (Family Aphidae), which are known to develop high populations during the summer as well as transmit viruses to cucurbit plants. Alate and apterous aphids are vectors for zucchini yellow mosaic virus (ZYMV). Standard cucurbit production practices include black plastic mulch accompanied by intensive insecticide or row cover use. In August 2018, ‘Multipik’ summer squash was grown in an open field on four different colors of plastic mulch—black, white, silver, and red. The objective of the study was to evaluate the effects of plastic mulch color on insect pest presence and movement as well as the diseases they can transmit. Two and three weeks after sowing, fewer alate aphids were trapped in silver mulch plots than in any of the other mulches except in week two where the aphid count in the silver mulch was not significantly different from the white mulch. In week two, the white mulch had significantly fewer alate aphids than in the red mulch and in week three the white mulch had fewer trapped aphids than in the black mulch plots. Three weeks after sowing, ZYMV was unexpectedly confirmed in all five experimental replicates. Four weeks after seeding, significantly more squash plants growing in red mulch (19%) were symptomatic for ZYMV, compared to the silver (1%) and white (2%) mulched plants. No statistically significant differences were apparent at two subsequent weekly counts, though squash in the silver mulch showed the lowest numerical ZYMV incidence. There were no significant yield differences among treatments. This study is being repeated in 2019.