We had some zucchini type squash this year like that. How did you get rid of the white powdery mildew on your squash leaves? Contrary to what you might think, powdery mildew on squash is not prevalent during wet growing seasons. But, all that is now behind us. Some squashes naturally have the silvery-looking color to parts of their leaves. Powdery mildew is a fungus that forms as a white or gray powder on the leaves of plants causing the leaves to become deformed and die. Fruit ends up less pocked as well. A mix of 1 tsp sodium bicarbonate per cup of water works very well. It didn’t bother the onions, garlic, asparagas, herbs, or new red and yukon gold potatoes. I mex it in a gallon sprayer and spray once a week. I sprayed right before dark and by the next afternoon the leaves had brown splotches all over. The house we bought has 1.5 acres of grass and it’s nuts with a push mower lol. Contrary to what you might think, powdery mildew on squash is not prevalent during wet growing seasons. Neem oil didn’t solve my powdery mildew problem. My various squash plants and pumpkins all got it My cucumbers did not, wish is odd as they are pretty close to some of the squash. The squash leaves with mildew die back, exposing the fruit to sunscald at its formative stage. You can harvest the same day you spray, no scary chemicals. I live in Norcal and I have a raised bed……I use drip lines….my teenage son installed. With it being so dry here, I anticipate watering every other day….so drip or sprinklers for raised beds? Cultural Control. Neem oil has it’s place, but it is not something I keep on hand. So how do you identify powdery mildew in squash? In addition to squash plants, it may afflict any number of veggies, including: However, there is a different species of powdery mildew that attacks each different veggie. A ready to use spray. First I removed infected leaves, and when it continued to progress, I then used an organic fungicide- spraying top and bottom of leaves- and I think I got it in time My squash is doing well. Sign up for our newsletter. LOL. Powdery mildew control may also be need to be combined with a timely application of a fungicide. It gets very humid and damp around here. sprinkling the leaves} and try making plant spacing less dense to increase air circulation. ah, this is what killed my pumpkins! Results w/in 48 hours. Sulfur and “Stylet” oil are effective products for powdery mildew control. yeah, yellow squash, zucchini, AND my cukes got is all bad this year, I did not know that it overwintered! Ended up with it a few years ago in starts I had purchased. Your email address will not be published. Powdery mildew fungi clog up leaf pores and block light to photosynthetic cells, so the plants are weakened in their ability to use light as an energy source. What do you do then? In fact, it only takes three to seven days from initial infection to appearance of symptoms. First time I’ve ever had this. My plant was smal then, I did nothing to treat it as I could not find anything online to say it was bad, and the plant is fine now. It is far more probable in areas that are damp, are somewhat shady, and have higher levels of humidity. Just remember that the powdery mildew can be transferred to other vegetables as well; it doesn’t just affect squash. Can you put infected plants in the compost?. Must be in the soil. Once week a solution of dawn soap 1tsp per gallon water, and then the dairy the following week. I had some beautiful squash plants with these silvery leaves that were totally thriving (until they were killed by vine borers..). My plants are now back to producing (albeit slowly) zucchini. My question is: if the leaves are gray in color and not powdery and otherwise healthy, can it be normal? They were small enough that we just dipped the leaves in the milk and it was completely gone with one treatment. I plan to plant squash in a different place next year but wonder what I can plant in the P.M. spot next year? {I would totally try this if my pumpkin patch wasn’t so big, it would take hours to apply! Neem oil is not harmful to bees! Read on to learn more. Also, powdery mildew in cucurbits is spread because the disease overwinters and is spread to successive generations of squash. Powdery mildew spreads rapidly and can travel a long distance. Not an issue here because it’s SNOWING. We dealt with it using neem oil. Woo Hoo! Major problem this year. I used to use skim milk (reconsituted dry milk) which works ok for PM. When using fungicides, it’s too late for them to be of any use once symptoms become rampant. Los Angeles is a dry climate, but with late summer rare humidity, we did get a lot of mildew on the squash. I do spray late evening as to avoid killing honey bees. Has this ever happened to anyone using this type of spray? Any idea what I might have on the zucchini plants? Snohomish WA over here. I thought you might like to know that your first picture up above does not look like a picture of downy or powdery mildew. If you get it, use MIlstop (Potassium Bicorbonate) to try and remove it before it gets too bad. Additional management techniques for treating powdery mildew in squash are to destroy any diseased plant debris, space plantings since a densely planted plot is more likely to be infected, and plant resistant varieties when possible. We have a shady-ish yard and humid summers, so I can see how powdery mildew would be a problem. I researched this like crazy when it happened to several of my squash plants and was relieved to learn that it did not cause any harm to the plant in terms of impacting production or killing the leaves. A solution of watered down milk will also kill powdery mildew. It only kills the bad bugs that eat the plants. I ended up just pulling them out. A great preventative measure to take if you ave ad problems in previous seasons is to alternate spraying once a week from the start of your garden. It appears on older leaves first, as reddish brown spots. Whatever you choose, remember the key is early application, before the disease is readily apparent all over the foliage. There is no powder. After field mice destroyed my canteloupe crop and pea crop I was sure they were gonners…till I get rid of the pests early September. If the mildew is left untreated, your squash is going to die. My cucumbers got it bad. Also, keep the garden free of weeds. To the store I go today…gonna try the neem. I also used Neem oil which can be purchased at most home improvement stores (Lowes, Home Depot, etc). It can spread rather rapidly so it is best to treat it as soon as you notice it. Not sure what happened. Before you realize it, your whole crop is brown, dead, and without any actual squash to eat. I like it because it is 2 in 1 product…pesticide and fungicide and is organic.