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Modifying row cover systems to manage bacterial wilt in organic muskmelon in Iowa, USA

Mark Gleason: Iowa State University

<div>The use of spunbond row covers on muskmelon is limited to early in the season, but organic insecticides used after row cover removal are ineffective and harm beneficial insects. Mesotunnels - nylon mesh row covers - could provide full-season protection with less insecticide use. Four systems were tested on muskmelon in Iowa during 2016 and 2017: spunbond low-tunnels removed at anthesis, mesotunnels removed for two weeks during pollination, full-season mesotunnels with bumble bees inserted for pollination, and a never-covered control. Insecticides were applied to non-covered plots based on economic thresholds for cucumber beetle. Full-season mesotunnels led to lower bacterial wilt incidence than spunbond low-tunnels and never-covered in 2016, but bacterial wilt was absent in 2017. In both years, full-season mesotunnnels had a higher weight of marketable fruit than never-covered control, but only in 2016 did full-season mesotunnels yield more than spunbond low-tunnels. The number of marketable fruit was greater for the full-season mesotunnels than other treatments in 2016, but yield enhancement was not significant in 2017. No insecticides were applied in the full-season mesotunnels, whereas spunbond low-tunnels required 2 sprays in 2016 and 1 spray in 2017. Mesotunnels may provide a way for organic muskmelon growers to achieve consistently high marketable yield with minimal need for insecticides.</div>