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EFFECTS OF ULTRAVIOLET‐B RADIATION ON FUNGAL DISEASE DEVELOPMENT IN CUCUMIS SATIVUS
Author(s) -
Orth Ann B.,
Teramura Alan H.,
Sisler Hugh D.
Publication year - 1990
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1990.tb13617.x
Subject(s) - cucumis , cultivar , biology , cucurbitaceae , horticulture , inoculation , spore , botany
Three cucumber (Cucumis sativus L.) cultivars were exposed to a daily dose of 11.6 kJ m ‐2 biologically effective ultraviolet‐B (UV‐B Be ) radiation in an unshaded greenhouse before and/ or after infection by Colletotrichum lagenarium (Pass.) Ell. and Halst. or Cladosporium cucumerinum Ell. and Arth. and analyzed for disease development. Two of these cultivars, Poinsette and Calypso Hybrid, were disease resistant, while the third cultivar, Straight‐8, was disease susceptible. Preinfectional treatment of 1 to 7 days with UV‐B BE in Straight‐8 led to greater severity of both diseases. Postinfectional UV treatment did not lead to increased disease severity caused by C. lagenarium, while preinfectional UV treatment in both Straight‐8 and Poinsette substantially increased disease severity. Although resistant cultivars Poinsette and Calypso Hybrid showed increased anthracnose disease severity when exposed to UV‐B, this effect was apparent only on the cotyledons. Both higher spore concentration and exposure to UV‐B radiation resulted in greater disease severity. Of the cucumber cultivars tested for UV‐B sensitivity, growth in Poinsette was most sensitive and Calypso Hybrid was least sensitive. These preliminary results indicate that the effects of UV‐B radiation on disease development in cucumber vary depending on cultivar, timing and duration of UV‐B exposure, inoculation level, and plant age.