Abstract
A technique using fluorochromes was developed to quantify the survival of Plasmopara viticola on the leaves of grapevine cv. Chardonnay following application of chlorine dioxide (ClO2). The staining combination of 5,6 carboxyfluorescein diacetate and propidium iodide produced intense green fluorescence of live conidia and red fluorescence of dead conidia of the fungal pathogen under blue excitation. The number of live conidia on the leaves emitting green fluorescence decreased significantly with increase in the concentration of ClO2. The percentage of dead conidia on leaves treated with 25 or 50 ppm of ClO2 were 38 and 99, respectively. No conidia survived on leaves treated with 100 ppm of ClO2. The bioassay can be applied to studies on screening fungicides for disease control. The advantages of the fluorochrome bioassay used in this study are that it is faster than measuring germination of conidia, and that it gives a quantitative estimate of survival of the pathogen.
| Original language | English |
|---|---|
| Number of pages | 3 |
| Journal | Australasian Plant Pathology |
| DOIs | |
| Publication status | Published - 2002 |
Keywords
- chlorine dioxide
- conidia
- diseases and pests
- downy mildew diseases
- fluorescence microscopy
- grapes