Population dynamics of Scutylenchus rugosus under cultivation of maize and wheat and survival in dry fallow conditions

Summary The ectoparasitic nematode, Scutylenchus rugosus, is common in Europe and Asia, feeding on several plant species and limiting productivity. Its seasonal population fluctuation was monitored on maize and wheat crops, in glasshouse and open field conditions, respectively. Its survival in the absence of a host plant was also investigated in a microplot field trial. The population of S. rugosus increased gradually during 4 months of maize growth in glasshouse conditions, and more than 50% increase occurred during the second month after sowing. Under wheat growth, in open field conditions, the lowest population was observed during July, 1 month after wheat harvesting, and the highest in August, after the first post-harvest irrigation. About 50% of the nematode population survived after a 5-month period of drought in the absence of a host and the percentage of surviving nematodes was greater under a dry soil regime than under a dry-wet regime. Most of the inactive S. rugosus were adults. After 24 h of soil wetting, most inactive nematodes resumed their activity and the optimum temperature for activation was 25°C.