Tough on Botrytis, soft on grapes.
Botrytis thrives and spreads rapidly in conditions that are consistently wet or humid. Once you have wet or humid conditions, it is temperature that determines how fast infection occurs – the optimum temperature for botrytis spore germination is 18-21ºC, however germination can still occur at temperatures lower than 10ºC and above 30ºC.
A film of free water is essential for spore germination. If the temperature is not in the ideal range than longer periods of wet plant surfaces are required for high levels of germination and infection.
Surface moisture for germination and infection does not come just from rainfall or irrigation – it can result from rain, dew, mist or fog. High humidity may even lead to sufficient condensation within crevices of tissues, such as flowers, to allow germination to occur.
Get our Botrytis technote to learn more.