Plastic Mulch and In-row Spacing Effects on Sweetpotato Yield in Northwest Washington

Sweetpotato ( Ipomoea batatas ) production in the northern United States is limited due to perceived barriers of a short growing season and relatively cool summer temperatures, yet recent studies have shown yield regions can be greater than national average when sweetpotatoes are grown with plastic mulch. A study was conducted northwest Washington evaluate productivity ‘Covington’ sweetpotato polyethylene (PE) soil-biodegradable (BDM) mulches different in-row spacings (20, 30, 38 cm) 2019, test accessions resistant wireworm Agriotes sp. Limonius sp.) 2020. In slips were shipped from North Carolina, after 4 days transit, 60% 70% died transplanting field. By end season, BDM deterioration reached 11% compared 0.4% for PE mulch, but there no differences mulch plant establishment, growth, yield, or proportion storage roots damaged by wireworm. Total root 22 t?ha ?1 15 BDM. Percent canopy cover greatest at 20-cm spacing later likely intermingling vines adjacent plants, whereas high percent 38-cm increased secondary per plant. (20.4 ), intermediate 30-cm (18.0 lowest (17.0 ). contrast, number produced (3.4). There more jumbo (3.4 (3 weight U.S. No. 2 grade (10.2 Soil temperature 3 °C under bare ground. However, 98% observed severely 10 20 holes root. For wireworm-resistant 2020, 16% wireworm, 1.7 4.0 PI 666141 04-791 (45.5 on average) (24.7 Overall, appear suitable Washington, low 2019 highlights importance healthy successful production. Future research should cultivars maximum adaptation region, techniques reduce damage including genetic resistance, economics producing regions.