Reflective Plastic Mulch but not a Resistance-Inducing Treatment Reduced Watermelon Mosaic Virus Incidence and Yield Losses in Squash

Abstract

Plant viruses, especially those transmitted by aphids in a nonpersistent manner, cause significant yield losses in cucurbit crops. Studies have shown that UV-reflective mulches can reduce insects from entering a crop with coincidental reductions in virus incidence. Treatment of plants with various forms of resistance-inducing agents have also shown promise for their ability to reduce plant virus incidence and associated losses. In this article, we describe a two-trial study that evaluated the integration of UV-reflective plastic mulch and a commercially available resistance-inducing treatment, BioYield™, to reduce the incidence and disease-related yield losses in summer squash [Cucurbita pepo var. melopepo (L.) Alef.] caused by the aphid-borne plant virus, Watermelon mosaic virus (WMV). In the spring trial, there was significantly reduced WMV incidence and whole treatment average enzyme-linked immunosorbent assay (ELISA) values among squash plants grown on silver-on-black (UV-reflective) mulch compared with plants grown on nonreflective black mulch. Significantly greater squash fruit yields were obtained for plants grown on the silver-on-black mulch relative to the black mulch treatment. In the fall trial, highly UV-reflective silver mulch was used in addition to silver-on-black and black mulches. WMV incidence and whole treatment average ELISA values were significantly lower for squash plants in the silver mulch treatment compared with silver-on-black and black mulch treatments. The silver-on-black treatment resulted in lower WMV incidence and whole treatment average ELISA values compared with the black mulch treatment. Squash plant yields were significantly greater for plants in the silver-on-black mulch treatment than for those in the silver or black mulch treatments. Treatment of squash plants with BioYield™ did not reduce virus incidence, or whole treatment average ELISA values, nor did it result in higher squash fruit yields compared with the nontreated control in spring or fall trials.