Possible mode of action of paraffin oil as a spray agent in the control of powdery mildew of grapevine
Abstract
Mineral oils (such as paraffin oil) have been used for a long time for disease control in vineyards. However the mode of action of this substance have not been studied yet. Our examinations highlighted that paraffin oils do not have a direct fungicide effect against neither the mycelia nor the conidia of Erysiphenecator, the causing agent of powdery mildew. The contradiction between this result and the disease control properties of paraffin oils can be eliminated by assuming that paraffin oils act directly on the grapevine itself, decreasing its susceptibility to powdery mildew. To test this hypothesis, comparative examinations were carried out with paraffin oil-treated and untreated leaves of VitisviniferaL. cv. Chardonnay. The treatment with the mineral oil was resulted in the elevated synthesis of secondary cell wall components like lignin and callose. Besides the secondary thickening of the cell walls in treated leaves, the synthesis of phenolic compounds was also increased due to the paraffin oil treatment. Since both secondary cell wall thickening and phenol synthesis are well-known processes during responses to abiotic and biotic stresses in plants, it can be assumed that the mineral oil acts as a stress inducer on grapevine. We hypothesize that the defense responses induced by the paraffin oil may decrease the susceptibility of grapevine leaves to powdery mildew.
Issue: GiESCO 2017
Type: Extended abstract
Authors
1 Research Institute for Viticulture and Enology, Eszterházy Károly University, Kőlyuktető, Eger, Hungary
2 Food and Wine Research Centre, Eszterházy Károly University, Leányka str. 6, Eger, Hungary
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Keywords
paraffin oil, grapevine, powdery mildew, disease control