What is the white powder substance?

Question

I have the leaves of my squash plants covered with a powder like substance, which, of course, does not look healthy at all. Is this killing my plants?

Answer 1

It is a fungus that will kill the plants. If not a fungus the it the blight. You need to ask the lawn and garden department what would be good to put on it. They will probably suggest an Ortho product.

Answer 2

might be powdery mildew..thrives on heat and humidity...

a good garden fungicide should take care of it

Answer 3

We just pruned our zucchinis, pumpkins, and cantaloupes yesterday because of the powdery mildew.  We cut the really covered leaves and washed the leaves with a solution of 1 gallon water, 1 Tablespoon baking soda and 1/2 teaspoon of liquid dish soap (not for the dishwasher but the sink).   I will keep my fingers crossed for the both of us!  

We live in a very humid area and I guess our plants were totally crowded.  This is our first year gardening so we're learning as we go...

Answer 4

I agree with Eddie that it is powdery mildew which a fungicide will take care of...the high heat and humidity and not enough air circulation (sometimes due to overcrowding) and over head watering all will cause this common problem...Try to water at the base of the plants (yes I know very time consuming and back breaking) but that will cut the chances of it happening in half...next year spread them a lil farther out from each other so they can have more air circulation and water in the mornings (overhead would be fine) thus allowing the morning son and heat to evaporate the water droplets...evening watering's and dew through out the night play a big part in the powdery mildew...

Answer 5

A white powder like substance?  My neighbor sprinkels a white powder on his squash plants to keep the squash bugs off.  It isn't supposed to hurt the plants.

Answer 6

There are a number of things it could be; it's nearly impossible to diagnose based solely on your description, but this might be what you're dealing with: http://www.extension.org/faq/508  Assuming you're in the U.S., you could give your local agricultural extension office a call and see what they think it might be.  You can find their contact information by going to extension.org, then enter your ZIP code in the box on the right-hand side and click Submit, and click on the link "Local offices near you" to see the website for the office in your area/state.

Local extension staff are usually the best resource for any gardening/plant questions because they're familiar with the area and what types of problems and issues can come up.  If they can't help you, the Master Gardener program for your state may have some advice: http://www.ahs.org/master_gardeners/inde...

Good luck!