Influence of Resistant Tobacco and Tobacco Cyst Nematodes on Root Infection and Secondary Inoculum of Fusarium oxysporum f. sp. nicotianae . J. A. LaMONDIA, Department of Plant Pathology and Ecology, Connecticut Agricultural Experiment Station, Valley Laboratory, P.O. Box 248, Windsor 06095. Plant Dis. 79:337-340. Accepted for publication 4 January 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0337.

The influence of Fusarium wilt-resistant broadleaf tobacco and Glohodera tabacum tabacum on infection and secondary inoculum production by Fusarium oxysporum f. sp. nicotianae was investigated under greenhouse and field microplot conditions. Wilt severity and postharvest F. oxysporum density in soil was greater for wilt-susceptible than wilt-resistant tobacco in all experiments. G. t. tabacum increased the number of F. oxysporum colonies recovered per centimeter of root for wilt-susceptible but not for resistant tobacco after 8 wk. F. oxysporum levels in soil were greater after plant infection by both F. oxysporum and G. t. tabacum than after plant infection by F. oxysporum alone. Wilt-resistant tobacco supported F. oxysporum densities that were intermediate between susceptible tobacco and fallow and significantly greater than fallow only after more than one season of production, regardless of nematode infection, under both field and greenhouse conditions