Growth, morphological alterations and adaptation of some plant pathogenic fungi to bentate and zineb. A new look
2003
Abo Ellil, A.H. | Sharaf, E.F. (Cairo Univ. (Egypt). Botany Dept.)
The fungicides bentate and zineb were tested in vitro on growth, sporulation and morphological alterations of Alternaria solani, Fusarium oxysporum and Sclerotium cepivorum. Reduction in growth criteria of the tested pathogenic fungi was more correlated with elevation of bentate dose than with zineb. The target fungi showed a limited resistance to zineb training transfers, but could tolerate up to 5-folds of sublethal bentate dose specially Sclerotium cepivorum. The pigmentation and the dark colour of colonies are the most morphological alterations occurring in the growth media, in response to toxic stress of both fungicides. Fifty and about 100% sectoring were incident just before LD50 and lethal dose respectively of both chemicals. Percentage increase of sectoring was associated with progressive reduction in sporulation. Tolerance of these fungi towards zineb, is correlated with increased ability to synthesize extracellular melanin under fungicidal stress. A new took to the mode of action of each fungicide was discussed in the light of current oxygen toxicology theory.
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