Plant Pathology (2014) 63, 548-553

J.C. Scott, D.N. McRoberts and T.R. Gordon (2014)
Colonization of lettuce cultivars and rotation crops by Fusarium oxysporum f. sp. lactucae, the cause of fusarium wilt of lettuce
Plant Pathology 63 (3), 548-553
Abstract: The severity of fusarium wilt is affected by inoculum density in soil, which is expected to decline during intervals when a non-susceptible crop is grown. However, the anticipated benefits of crop rotation may not be realized if the pathogen can colonize and produce inoculum on a resistant cultivar or rotation crop. The present study documented colonization of roots of broccoli, cauliflower and spinach by Fusarium oxysporum f. sp. lactucae, the cause of fusarium wilt of lettuce. The frequency of infection was significantly lower on all three rotation crops than on a susceptible lettuce cultivar, and the pathogen was restricted to the cortex of roots of broccoli. However, F. oxysporum f. sp. lactucae was isolated from the root vascular stele of 7·4% of cauliflower plants and 50% of spinach plants that were sampled, indicating a greater potential for colonization and production of inoculum on these crops. The pathogen was also recovered from the root vascular stele of five fusarium wilt-resistant lettuce cultivars. Thus, disease-resistant plants may support growth of the pathogen and thereby contribute to an increase in soil inoculum density. Cultivars that were indistinguishable based on above-ground symptoms, differed significantly in the extent to which they were colonized by F. oxysporum f. sp. lactucae. Less extensively colonized cultivars may prove to be superior sources of resistance to fusarium wilt for use in breeding programmes.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Thomas R. Gordon

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Fusarium oxysporum f.sp. lactucae	Cabbage (Brassica oleracea)
	Fusarium oxysporum f.sp. lactucae	Lettuce (Lactuca)
	Fusarium oxysporum f.sp. lactucae	Spinach (Spinacia oleracea)
	Fusarium oxysporum