One fungal disease of vegetable plants and some fruit trees which is debilitating is powdery mildew. It affects the foliage and stems by covering them with patches of white mould (mold). In the worst cases, those leaves end up distorted, swollen and eventually dying.
The worst affected plants are gooseberries and blackcurrants (most Ribes in fact), grapes, courgettes, marrows and all members of the Rosaceae family. Different strains attack different crops so there are variations in the level of damage. Just look for cultivars and varieties which show resistance to this problematic mold.
Reducing the Level Of Infection
The best way to keep the level of infection down, and by the way, it can never be fully eradicated, is to water well especially during times of dryness. Always mulch well around the crop as this provides a barrier to dryness and keeps up humidity levels.
destroy any affected foliage as soon as possible because once it take hold, it soon spreads rapidly. Fungicides can be used because it treats the leaf surface. This specific targeting means other parts of the plant especially the fruit are kept fungicide free during spraying.
Look out for mildew resistant crops, there are varieties which are capable of resisting the onslaught of this problem fungus.
I noticed this year (2017) that powdery mildew was really bad on my roses especially during that very dry early summer we had. It certainly ruined the look of all my plants and I’m certainly looking for fungicides that deal with it really well. If you catch it early enough, it doesn’y become such an issue but it really cheesed me off this year.
I’ve lost a lot of vegetables especially my courgettes to this disease this summer. Just wish there was a decent fungicide – I literally pulled all the leaves off which showed slight signs of infection and it never keopt it off. I think som many of my plants in Germany were affected that I was never going to get rid !
Really – not a great year for me either with mildew. Destroyed a lot of my squashes. I will probably not grow so many next year !