Phytopathology (2022) 112, 364-372

Sukhwinder Kaur, Radwan Barakat, Jaskirat Kaur and Lynn Epstein (2022)
The effect of temperature on disease severity and growth of Fusarium oxysporum f. sp. apii races 2 and 4 in celery
Phytopathology 112 (2), 364-372
Abstract: Fusarium oxysporum f. sp. apii race 4, which is in F. oxysporum species complex (FOSC) Clade 2, causes a new Fusarium wilt of celery. We compared F. oxysporum f. sp. apii race 4 with race 2, which causes Fusarium yellows of celery and is in FOSC Clade 3. Optimal temperatures for celery yield are 16 to 18°C. Soil temperatures in California celery production areas can range up to 26°C, and the maximal rate of hyphal extension of F. oxysporum f. sp. apii races 2 and 4 in culture are 25 and 28°C, respectively. Here, we compared the effect of temperatures from 16 to 26°C on growth of F. oxysporum f. sp. apii races 4 and 2 in two celery cultivars: Challenger, which is resistant to F. oxysporum f. sp. apii race 2 and susceptible to race 4; and Sonora, which is susceptible to both F. oxysporum f. sp. apii races 2 and 4. Based on linear regressions, as temperature increases, there is an increase in the log of F. oxysporum f. sp. apii race 4 DNA concentration in celery crowns and in the reduction in plant height. Based on logistic regressions, as temperature increases, the incidence of vascular discoloration increases in celery with either F. oxysporum f. sp. apii race 2 or 4 infection. In both cultivars, temperatures of 22°C and above resulted in a significantly (α = 0.05) greater concentration of F. oxysporum f. sp. apii race 4 than race 2 in planta. The concentration of F. oxysporum f. sp. apii race 2 in crowns in 'Challenger' is temperature-independent and comparatively low; consequently, 'Challenger' is, at least partly, resistant rather than tolerant to F. oxysporum f. sp. apii race 2.
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Link to article at publishers website
Database assignments for author(s): Radwan Barakat, Lynn Epstein

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
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. apii	Celery (Apium graveolens)	U.S.A. (SW)