Suppressive effect of rye cultivation on soil populations of the northern root-lesion nematode, Pratylenchus penetrans (Cobb) in Hokkaido.

Abstract

Suppressive effect of rye cultivation on soil populations of the northern root-lesion nematode, Pratylenchus penetrans (Cobb) In a pot test with soil infested with the northern root-lesion nematode, Pratylenchus penetrans, conducted to examine nematode development in plant root tissue and nematode populations in soil, no nematode eggs were found in the root tissues of 7 cultivars of rye and triticale among 35 cultivars tested. In a spring seeded experiment, 5 of the 7 cultivars which had no nematode eggs in root tissue were grown for 2 months from the end of May in nematodeinfested field plots. The experiment was repeated twice in two successive years with each year having a different population level of 92 and 52 nematodes/25 g of soil, respectively. A nematode suppressive effect was found in the "BILBAO" and "WIANDI" plots, but the effect was lower than that in the control plots planted with a commercially available antagonistic plant, Avena strigosa "Hay oats". Proportions of marketable radish grown after rye for two successive years were respectively 43% and 73% in the "BILBAO" plot, 3% and 30% in the "WIANDI" plot, and 100% for both years in the A. strigosa plot. In the autumn seeded experiment, rye plants were grown from 27 September to 12 June the following year in nematode-infested field plots (45 nematodes/25 g of soil) with or without a fungicide application for snow mold control. The nematode Pf/Pi ratios were 10% for "SBR601" (newly tested breeding line), 23% for BILBAO" and 24% for "WIANDI" in the plots where crop growth was protected by the fungicide application. Proportions of marketable radish grown after rye were 90% in the "SBR601" plot, 60% in the "BILBAO" plot and 67% in the "WIANDI" plot. The suppressive effect on nematode populations was found to be higher in "SBR601" than in the other two cultivars. Nematol. Res. 39(1), 31-43 (2009).