Hi!
Please see attached pictures of my melon seedlings , I am curious if this is powdery mildew. If so how do I cure it and prevent it ? Please suggest a few products.
Secondly, last year I believe I experienced blight and powdery mildew in my garden. What fungicides can I use to prevent this issue again. FYI I am plantings melons tomatoes peppers gourds etc.
As I read online it seems I would have to cycle between atleast 3 fungicides, which was very confusing as they mentioned the MARC values.
Please recommend some products!
Thank you very much!
Thank you for contacting the Toronto Master Gardeners.
Since you suspect you experienced problems with powdery mildew before, it is understandable you would like to be vigilant this year! From the photo you shared, it is hard to diagnose whether that is the beginning of the condition on your seedlings, so keep a close eye on them to see if powdery mildew develops or worsens (i.e., a grey-white, dusty-looking coating on the surface of leaves or other plant parts).
Good garden practices can help to prevent the spread of this disease. During hot humid weather, powdery mildew attacks many herbaceous plants especially ones that are stressed due to drought. To help control it, space or prune plants to create good air circulation and water well during hot spells, taking care to water the soil and not the plant leaves. Remove and dispose of any diseased leaves in the garbage. Do not compost them as the spores will remain viable so can spread to other susceptible plants.
If powdery mildew should develop despite your best efforts, to combat the fungus this season try using a bio-fungicide containing Bacillus subtilis. You can also use fungicidal soap, sulfur or lime-sulfur sprays but check the instructions on the container carefully to make sure these products can be applied to the affected plants.
For more information see the Gardening Guide Toronto Master Gardeners has prepared on the topic:
Here’s to a great gardening season.