Downy and Powdery MildewMay 20, 2019
The terms powdery and downy mildew – refer to a group of phytopathogenic fungi that cause diseases in plants and appear similar.
They usually occur on young leaves and stems, although this is not always the case. The aspect that the leaf or the stem offers is as if you were covered with dust (powdery mildew) or irregular brown or purple spots (downy mildew).
Both develope favorably under conditions of high humidity and temperature.
But there are some differences in the optimal conditions for the development of these diseases:
For POWDERY MILDEW (Sphaeroteca pannosa)
- Relative humidity: 30 – 40%
- Temperatures: high, over 25-28 ˚C
- The spores are carried by the wind
For DOWNY MILDEW (Peronospora Sparsa)
- Relative humidity: 70 – 85%
- Temperatures: low, over 12-15 ˚C
- Systemic disease, affects stems and leaves, tender shoots.
Both types of fungi are highly contagious and spread very easily. It is better to detect the disease from the green house, then during the packaging process and finally in the cold room of the cargo agency. This is the only way to reduce the considerable loss of flowers and values invested in their transportation.