The mildew is a fungus, there are several species but they all basically have the same effect on your veggies. White powdery spots appear on leaves, undersides of leaves and stalks. If left unchecked they can spread to form a dense layer of thick white powdery spores. Eventually the mildew will cause leaves to turn yellow, die and fall off – it looks a lot like an icky alien infection.
Powdery mildew often affects cucumbers, lettuce, melons, parsley, pumpkins, potatoes, peas, eggplant, pepper, tomato, strawberries, beans, grapes, and tree fruits but it’s most favorite victim is squash!
The fungus acts fast so your best defense is to act quickly. First – remove any damaged leaves. These spores can easily spread to other plants so wash any tools you use afterwards since the spores could be hiding and waiting to be carried to their next host plant. The spores can also winter over in the soil or on plant debris so it’s a better idea to dispose of infected leaves in the trash as opposed to your compost bin.
You know how when you chop off the arms of a zombie they just keep coming after you? It can be very similar when dealing with powdery mildew, simply removing leaves seldom keeps the problem in check for long but there are solutions for staving off the hoards of advancing spores.
Several recent studies have shown that 10% milk mixed with water and sprayed on leaves works just as well as synthetic fungicide or sulfur. Applications should be made once a week to keep the fungus under control.
Mix 1 Tablespoon baking soda with 2.5 Tablespoons of horticultural oil and spray on leaves. This solution will also need to be applied weekly.
Garlic extracts should be diluted 1:10 with water and applied to leaves. This also works on vampires but the concentration needs to be much higher.
Vegetable oil mixed 2.3 Tablespoons per gallon of water and a teaspoon of biodegradable liquid soap. Neem oil diluted 2 teaspoons per gallon can be applied every other week. Mint oil and Rosemary oil can also be very effective. Again weekly applications to the leaves is best.
As a last resort there are commercial fungicides treatments available but are those zucchini really worth the real life horror stories of the long term effects of fungicide use.
Fungicide residues can wash off and find their way into our aquatic systems where they wreak havoc. They also build up in the soil resulting in an accumulation of copper that can pose risks to the long term fertility of the soil and have adverse effects on the organisms and microorganisms like earthworms that help maintain healthy soils healthy gardens healthy people and healthy communities.
As the arsenal of chemicals that humans use to control the environment continues to expand I sometimes wonder if we are the monsters in this horror flick!