Harbach Chelsea J, Tylka Gregory L
Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011.
Plant Dis. 2022 May;106(5):1486-1491. doi: 10.1094/PDIS-12-20-2581-RE. Epub 2022 Apr 6.
Greenhouse experiments were conducted to determine if cover crops directly decrease population densities of the soybean cyst nematode (SCN), , and/or have residual effects on reproduction of the nematode on soybean (). Population densities of SCN were not significantly decreased by nine cover crop plants or three cover crop mixes compared with a non-planted soil control in a repeated 60-day-long greenhouse experiment. When susceptible soybeans were grown in the soils after cover crop growth, fewer SCN females formed after three annual ryegrass () cultivars (Bounty, King, and RootMax), the Daikon radish ( var. ) cultivar CCS779, Kodiak mustard (), and a mix containing cereal rye, crimson clover (), plus Daikon radish (cultivars not stated) compared with following the non-planted control. In another repeated experiment, cover crops were grown for 56 days in SCN-infested soil in the greenhouse then exposed to Iowa winter conditions for 28 days to simulate winter termination of the plants. One treatment, a cover crop mix containing 'Bounty' annual ryegrass plus 'Enricher' Daikon radish, had a decrease in SCN population density greater than the non-planted control at the end of the experiment. Significantly fewer SCN females formed on soybeans grown after several cover crops, including the three annual ryegrass cultivars that had the suppressive residual effects in the first experiment. In summary, there were no cover crop treatments that consistently decreased SCN population densities across experiments, and only one cover crop treatment in one experiment significantly reduced SCN population densities more than a non-planted soil control. However, there was a somewhat consistent, adverse, residual effect of cover crops on reproduction of SCN on susceptible soybeans after growth of multiple cover crops.
开展了温室试验，以确定覆盖作物是否能直接降低大豆胞囊线虫（SCN）的种群密度，和/或对大豆上该线虫的繁殖产生残留影响。在一项为期60天的重复性温室试验中，与未种植的土壤对照相比，9种覆盖作物植株或3种覆盖作物混合物并未使SCN的种群密度显著降低。当在覆盖作物生长后的土壤中种植易感大豆时，与未种植对照相比，在3个一年生黑麦草（Bounty、King和RootMax）品种、大根萝卜（Raphanus sativus var. longipinnatus）品种CCS779、科迪亚克芥菜（Brassica juncea）以及一种包含谷物黑麦、绛车轴草（Trifolium incarnatum）和大根萝卜（品种未注明）的混合物之后，形成的SCN雌虫较少。在另一项重复性试验中，覆盖作物在温室中SCN侵染的土壤中生长56天，然后暴露于爱荷华州的冬季条件下28天，以模拟植物的冬季终止。一种处理，即包含“Bounty”一年生黑麦草和“Enricher”大根萝卜的覆盖作物混合物，在试验结束时SCN种群密度的降低幅度大于未种植对照。在几种覆盖作物之后种植的大豆上形成的SCN雌虫显著减少，包括在第一个试验中具有抑制残留效应的3个一年生黑麦草品种。总之，在各项试验中，没有哪种覆盖作物处理能持续降低SCN的种群密度，且在一项试验中只有一种覆盖作物处理使SCN种群密度比未种植的土壤对照显著降低更多。然而，在多种覆盖作物生长后种植易感大豆时，覆盖作物对SCN繁殖存在某种程度上一致的不利残留影响。
