Powdery Mildew

What is powdery mildew? This fungus disease affects a wide variety of plants, including lilacs, phlox, roses, squash, beans, and peas. It takes away a plant’s nutrients, which causes the plant to bloom less and become weaker. In some cases, if the infection is severe enough, powdery mildew can kill your plants. 

How to Identify Powdery Mildew

Plants infected with powdery mildew look as if they have been dusted with flour. It usually starts off as circular, powdery white spots. It usually covers the upper part of the leaves and affects the older leaves first; the leaves turn yellow and dry out. The leaves, buds, and growing tips will become distorted as well. These symptoms usually appear late in the growing season. 

How to Control Powdery Mildew 

  • Rubbing the infected leaves together can help partially remove the disease from your plants.
  • Remove all the infected plant parts and destroy them. Remember, do not compost any infected plant, as the disease can still be spread by the wind.
  • Spray infected plants with fungicides. Effective fungicides include sulfur, lime-sulfur, neem oil, and potassium bicarbonate.


  • Plant plants that are resistant or tolerant to powdery mildew.
  • Powdery mildew thrives in hot and humid weather, so avoid overhead watering to reduce humidity. Also selectively prune overcrowded areas to increase air circulation; this also helps reduce humidity for your plants.
  • Spray your plants with fungicides according to their directions. If you don’t want to use fungicides, try spraying your plants with a solution of 1 teaspoon baking soda in 1 quart of water. Remember to spray your plants thoroughly.


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This link said

This link said BlackSpot/Powdery Mildew. Are these different? I have black spots & yellow leaves on nearly every rose I plant in my garden but I don't have anything that looks like the powdery mildew description. Where can I find the best help for getting rid of Black Spot? My Hybrid Teas only last a maximum of 3 years before they succumb to this disease, it eventually ruins the canes and rots the root-stock. Thanks.

Oh, dear. Black spot is

Oh, dear. Black spot is common to roses the world over and there may be as many opinions on this as there are rose varieties. Some say that cleaning the ground of leaf debris at the end of season and then again in spring is the solution, as well as pruning the infected canes, avoiding wetting canes on gray (cloudy) days, and avoiding planting roses too close together. Others suggest that in combination with control agents such as the fungicide chlorothalonil (Daconil), reapplying it after rain and applying it to all new leaves (applications in 7 to 10 day intervals have been proposed). Another suggests Funginex. Some say fertilizing roses with Epsom salts helps. And then there is choosing plants that are resistant to black spot.
Finally, you might also consult your local agricultural extension service for local advice and/or notice where roses thrive in your vicinity and ask the property owner how they handle or avoid this plague. Best wishes!

Rose Red77-I live by the

Rose Red77-I live by the seaside and have finally given up on having roses because of blackspot.The best treatment is to spray very frequently (weekly),rake under the roses getting all the infected stuff away from the plant,and buying roses that are blackspot resistant. There are websites that teach about blackspot.You have to do a little searching for them though. Hope This Helps!

Please help.--My home is in

Please help.--My home is in Turkey, (ex pat).Earlyier this year i returned from the uk bringing with me two 5ft conference pear trees (my favorite). Reading all the info about pear trees, i purchased another euoropean tree to cross polonate.--well i waited ,and in the begining of June the buds started to open NO flowers, It seemed happy with the position i planted it in,leaves and shoots started to appear . Now they have stopped growing the leaves a little curlled but still very green. Q. We have another 8 weeks of hot sunshine 35c untill it starts to cool down, could that be the case of it being to hot. All my other fruit trees do not seem to be affected --Apple,Peaches, lemon, & orange. ----PS, It would be an good idea to include the temptures that most plants can endure in artcles writen . Regards Michael. Trudgeon.

I just got my phlox in

I just got my phlox in July.Planted it now all the leaves have brown spots. Asked nursery told me it has that mildew.How can I tell if the whole plant is dead? I trimmed it as much as possible. Thank you for ur time.

Yes, powdery mildew is a

Yes, powdery mildew is a well-known nuisance on phlox. Usually, this is not a serious enough problem to kill the plant in its first season, but cut back all the disease and remove the stems this fall (after frost) s the fungus does not survive the winter. In the spring, watch for new development and spray the foliage with a fungicide or dust with sulfur. Also, make sure the plants are well spaced to allow good air movement throughout the foliage. Water plants early in the day so leaves dry quickly.
Do not over fertilize (especially with nitrogen).

I have two sun flowers one

I have two sun flowers one about 6 feet the other about 4and a half the small one all the leafs started to wilt couple of days ago now the tall one is doing the same the smaller one large flower three buds and the tall one has a very large flower what could be causing this any help would be appreciated thank you

Usually, sunflowers wilt

Usually, sunflowers wilt because they need more water. Water every day to every other day and see if they perk up.  Sunflowers also naturally drop as their seed heads get heavy and they protect the seeds from the sun; this is a natural part of the cycle.

I spend hours everyday in my

I spend hours everyday in my garden caring for plants I have raised from seeds. My plants are over-ran with powdery mildew. Especialy my peonies and ALL vines, watermelon, gourds, cantalope ect. Then there's the aphids. Every plant in the yard is covered with a disease and bugs. Also have a big problem with atleast 4 ant species. I'm really dissapointed this year. I'm happy everything grew but honestly the plants look terrible. I grow hibiscus, roses, spider plants, coneflowers, morning glorys, clematis, hot poker, iris and many more plants that attract birds and butterflys. My daylillies and grasses look terrible too... ANY suggestion?

See the tips above and

See the tips above and comments from our reader for help with mildew. We have also heard that spraying a milk/water solution on the leaves will help. Use about 30% milk and 70% water. It doesn't matter what kind of milk you use.
For the aphids see our pests page at www.almanac.com/content/aphids
For ants you can sprinkling cinnemon or corn meal or spraying a little bit of vinegar between the plants.

My Rose bush has Black Spot.

My Rose bush has Black Spot. Is there a home remedy to remove the Black Spot?
Thank You

First, prune off the damaged

First, prune off the damaged parts of the plant and dispose of the diseased material in bags or burn it. Do not add to the composter.
One home remedy is a solution made with baking soda: dissolve 1 teaspoon baking soda in a quart of water, add a few drops of liquid soap to the mix to help it cling better to the foliage, spray infected plants thoroughly. Another unusual remedy for fighting fungal diseases is manure tea. This formulation fights blackspot, as well as mildew and rust, while providing foliar nutrition. Place one gallon of well-composted manure in a 5-gallon bucket and fill with water. Stir the mixture well and let sit in a warm place for three days. Strain the mixture through a cheesecloth or mesh and use the resulting tea to spray disease affected plants.
Remember to water your rose plants at soil level and avoid getting the leaves wet. Water in the morning. Space the plants well to ensure good air circulation. Smaller rose bushes be spaced 3 feet apart and larger rose bushes be spaced 4 feet apart from one another.

Last year was my first year

Last year was my first year growing a garden by myself. All the vine type plants (pumpkins, squash, melons, etc.) were killed by powdery mildew. They were doing great at first, by the end of summer the powdery mildew spread and rotted all the fruit and veggies. It was suggested to me that I burn the garden last fall, but I didn't get a chance to do it. In a month it will be time to plant the garden again. Will the mildew come back because I didn't burn the garden? Is there anything I can do now before I plant to prevent the powdery mildew from returning?

Some sources advise burning

Some sources advise burning the infected plant materials that were affected with powdery mildew in the same season. Hopefully, you at least cleaned the garden of any infected plants. If you have not yet, do that as soon as you can and avoid shaking any residue that might be infected into this year's garden bed. The spores can overwinter on affected plants and it can fall off as you move plant residue.
As for this season, plant resistant varieties for better results. Plant in full sun. Avoid excess fertilizer (hard to know how much for you would be "excess"; follow fertilier guidelines). Provide youor plants with good air circulation; give the adequate (or slightly more) space between each.
If you do see signs of powdery mildew returning, prune to remove the infected branches or shoots as soon as you can. 
We hope you have a happy harvest this year.

Pumpkins are heavy feeders

Pumpkins are heavy feeders and I would plant them in a different area this year. Be shure to feed your last year's garden with a good compost or other natural amendments. I always rotate heavy feeders every year and plant a cover crop to till in for the following year. Burning diseased plants or putting them in the trash is a good idea. I wouldn't plant a heavy feeder in the same spot for two or three years. If you don't have the room to rotate then feed the soil heavily. I like a mulch of at least 6 to 8 inches but pull it aside to get your plants into the soil. Happy gardening!

The top of our raspberry

The top of our raspberry plants are dieing. what causes this?

how do I keep Beatles off

how do I keep Beatles off rose bushes

This is our powdery mildew

This is our powdery mildew page.  You can find more information on our Roses page as well as our Japanese Beetles page here:
You need to handpick these beetles and drop into pails of soapy water. You could also place fine netting over the rose bush.  Another idea is to get ride of the grubs in the lawn with Milky Spore. Finally, you could use an insecticide; speak to your local garden center about what's approved in your area.

I bought a lilac bush (a

I bought a lilac bush (a young plant) a few months ago and a few days later I noticed it had powdery patches on it. I suspect it is powdery mildew. I planted it in my backyard a month ago. I didn't know what to do about the powdery patches so I haven't done anything about it yet. My lilac bush hasn't grown at all since I bought it and this concerns me. It is in partial sun--it gets the sun from the morning, and is shaded by trees in the afternoon. Any suggestions? Does it just take forever to grow? Will the powdery mildew kill it if I don't do anything? Please reply with suggestions. Thanks.

Your lilac tree is still

Your lilac tree is still young and you just planted it. It will grow more in the spring and next summer. Powdery mildew is common on lilacs after a hot humid summer. It's not going to hurt your bush. Lilacs need about 6 hours of full sun a day to bloom well. Go to our lilac page to find more tips about growing lilacs.

hey i had powdery mildew bad

hey i had powdery mildew bad last year and my buddy had the same issue so we figured a little cure searching was in order so after losing all of my tomatoes and most of my peas i found this stuff called cuh2o and i guess all this is, is copper and water when i called the number the people told me it was used for years and so i asked whats so special they literaly just told me its the copper suspended in watter and its pattend or whatever yadda yadda epa yada all that jazz and so i says send me a bottle and man with in the week i called em back and gave them my blessing cuz it kicked butt i mean i now have no sings of powder and it dont leave the nasty residue but any who ill share the number with you so u can combat and rid your plants of mildew your not alone with the problem and it dose suck the life out of em but ya heres the number 616-226-6539

I have powdery mildew on my

I have powdery mildew on my sunflowers and it killed them off and I would like to know if it will go away or do I have to remove my dead sunflowers and plant new ones next year? I really hope next year they will come back or can I do something now before the summer ends? I live in Tampa Fl where it is the start of the rain season every afternoon.

Hi Jessica, You need to pull

Hi Jessica,

You need to pull up and destroy the dead sunflowers.
You can try to plant new seeds in a different area of your garden. Plant the seeds in full sun and space them so that they will have good air circulation. For prevention spray with a neem oil spray or a mixture of 1 teaspoon of baking soda blended into a quart of water.

I to am having trouble with

I to am having trouble with black spots and powdery patches, thanks for all the information...My question can the water from a water softner harm roses or any plants?I planted 20 roses lost 10 and other annuals.......

It's OK for a little while

It's OK for a little while but not advised for the long-term due to the build-up of sodium. Water softeners take away calcium and magnesium and then leave sodium in the water. It is better to use the outside tap runs off the mains. Rain water, tap water, purified water, and boiled water are better options.

my pumpkin plant is severely

my pumpkin plant is severely infested with white powdery mildew after a week or two of rain. With more rain to come, is there a chance that spraying the leaves will help save the vines, or should I tear them out before it spreads?

Several sources we consulted,

Several sources we consulted, Jesse, say that your pumpkins will be ok, esp this late in season and esp if they are strong and healthy otherwise. Dampness is not the best thing. Spraying, esp  with rain coming that may wash off the spray, may not be the best solution. If you do want to spray, consult a nursery about horticultural oil of a biological fungicide.
In future, consider planting resistant varietes, give the plants plenty of room to grow, and certainly full sun.
Here's hoping you get this before the rains!

I have powdery mildew on my

I have powdery mildew on my pumpkin plants (took me a while to realize what it was) and I have 8 pretty big pumpkins on them at the moment. half the leaves have died and we still have 1.5 months to go before halloween comes along. Can I save my pumpkins? if yes how? do I need to cut them off right away or can I leave them to mature a bit more? I dont want to cut them off now and they rot before halloween comes! Thank you!!

Test to see if your pumpkins

Test to see if your pumpkins are mature: press the end of yout thumbnail into the flesh of the fruit; if little indentation is left in the fruit, the pumpkin is mature.
You could target the powdery mildew with spray, if it is not covering most of the plant. Consult a nursery for a recommendation.
When the plants are done, remove all of the decayed plant material to reduce overwintering fungus. Avoid fertilzing with too much nitrogen. Next season, avoid crowding plants.

Do I need to treat pumpkins

Do I need to treat pumpkins (whose leaves had powdery mold) when I harvest them? I'm wondering if I should wipe them, or at least spray the stems, with a disinfectant.

Powdery mildew should not

Powdery mildew should not affect your pumpkins now that the skins are hardened and cured. It is a fungus that grows on the surface of leaves and some fruit.

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