Yeah I will do this moving forward for sure.
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[quote=“JoeCrowe, post:658, topic:36891, full:true”]
so this eliminated a powdery mildew infestation? Tell us your story.
[/quote] A local indoor grow had mites and powdery mildew out of control they were using sulfur burners sticking up the neighbor hood . They had clones sitting out infested I took a couple home and treated with doctorzymes and killed the mites and the mildew . They loved the results and sprayed the green houses and the indoor and saved there grow . Just my two cents I still use it for mites mildew aphids no residual chemicals or smell / taste . I’ve grown a long time and have never used sulfur . This was hundreds of plants that were sick I used a lot of home made sprays but nothing worked like the zymes .
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Are you still using it weekly or so? Does it kill the mildew, or will come back if you stop spraying?
Either way, good to know of another decent product for the Arsenal. I’m doing weekly or every other week IPM treatment until it is freezing out again.
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yah whats the protocol? Like I spray that shit on there once and all bugs and fungus are dead to never return?
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It would be nice if it was sold in Canada .
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No it’s like anything else you need to pay attention to your grow . So far this season no problems last season it was aphids I had to spray several times . It worked great and no mildew no bud worms . I don’t have the mildew problems this time of the year its too dry here . But I grow outdoors with plenty of dry wind . But I used this product in my grow tent to kill off a few mites that came with the clones . Its whatever works for you I just don’t want smelly compounds on my smoke .
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yah, when you are eradicating the mildew never spray in bud. I would never recommend spraying anything but water on budding plants.
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no different than all the stuff I’ve been smoking all the way up till this past couple years.
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lol that was a photo I took of myself and turned into a cartoon with the caption ripped straight from the study on illegal cannabis. Frankly I was not surprised by the results, after the shit I’ve seen.
I sulfur sprayed some plants that I just flipped (no flowers yet), and the ones that have buds are getting mammoth canacontrol as a precaution. Using up to two weeks before harvest, then after chopping I’m going to wash the buds in some water with hydrogen peroxide mixed in.
Maybe it’s overkill since I haven’t seen any other infected plants, but I know there’s the chance they were exposed so everything gets treated.
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That’s why I suggested this stuff it worked right up though budding . Our problems are closer to the end off season starts cooling off possible early rains saved more than one grow . I just smoked a bowl of Vanilla Frosting sprayed with this stuff seems to work real good Happy Growing JoeCrowe
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Will hot weather kill mold and mildew ? seems both like the dampness . I don’t remember having mold and mildew problems until wet weather any Northwest coast growers growers on here .
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Here’s the thing gramps, and I know this will probably be offensive. The powdery mildew is a replicating pathogen, so you have to have a host plant infested with it, close enough to your crops, in order to get the mildew on your cannabis plants. If you kill the mildew off first, then plant the plants, you won’t see mildew again, even in the rainy season. Rain and high humidity brings what’s known as botrytis aka bud rot/mold, a kind of fungus that eats your buds from the inside.
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50 feet away is most likely close enough and hundreds of plants . No offense taken different problems at different times of the year . I know what bud rot is its been a very small problem also late in the season . Have you taken offense because I don’t use sulfur lol .
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These same spores can also lie dormant in the soil for years so if the area has been infected in the past, it could reappear once conditions for the disease are favorable.
As soon as the soil is tilled or disturbed or new growth changes the soil structure, the spores can become active and infect plants.
Other infected plants or weeds in the area could also transfer the disease to healthy plants. This can happen over relatively long distances so while your area might be safe, spores could travel from neighboring properties.
No moisture is necessary for infection, unlike most other fungal infections.
High temperatures 90°F / 32°C plus tend to slow down the spread as does rain. Having said that, the spores of powdery mildew can survive harsh winters. Although they will become dormant they can flare up again when conditions are more favorable.
What does powdery mildew do to your plants?
The fungus sends out threads into the plant as it develops. These fungal threads (haustoria) absorb vital nutrients from the infected plant. While they generally appear on the leaves they can also be present on the stem and later the fruit, buds, and other areas.
They are host-specific. In other words, certain fungi prey on specific plants. Again, there are hundreds of varieties so they attack a wide range of plants.
In some respects, this could be good news. The powdery mildew on your tomatoes, as an example, is unlikely to attack your roses. That is not to say you can be complacent as the fungus spreads rapidly and can quickly attack a range of plants.
The other bad news is that, although not fatal, powdery mildew will weaken the plant. This not only affects growth and flowering or yields, but also leave the plant more susceptible to other disease, insects, and problems.
A healthy plant is tough and can often handle most problems. One weakened by a fungal infection will not be able to put up much of a fight.
How to treat powdery mildew
Powdery mildew can affect more 10 000 species of plants so it is important to always keep a careful eye out for it and treat it as quickly as possible.
Despite not killing the plant, in most cases, it is a menace that you do not want on your plants. It spreads rapidly so the sooner you can treat it the better.
As with most diseases and pests, they tend to prey on plants that are weak or in poor health. Most strong plants are more resilient. We will get to how to prevent powdery mildew but let’s first look at what to do if your plants are already infected.
There are several ways to go about treating this fungal disease. One option is to treat with commercial products which are generally chemical fungicides.
You can get commercial products that are based on organic ingredients. The other option is using natural products you can mix yourself, some might call them home remedies.
Both chemical and organic products can be effective options depending on the severity of the infection, their environment, and the type of plant.
We will look at all options. You might need to experiment a bit in order to determine which is best for your situation. Often a combination is recommended.
Home solutions
Baking soda
A safe, inexpensive, and effective home solution is a solution of sodium bicarbonate (baking soda). It has many amazing uses in the garden and preventing and treating powdery mildew is just one of them.
To make this, simply mix a teaspoon of baking soda in water (1 quart/ 950 ml). Using a spray bottle, drench the plant in the solution. It is only effective where it makes direct contact.
You can improve on this mix by adding a horticultural oil. Simply add just over two tablespoons of the oil to the mix above.
As with many of these treatments, they need to be reapplied frequently. Once or twice a week is the minimum.
Remember that excess bicarbonate buildup in the soil will slow the absorption of iron and reduces magnesium and calcium. Always monitor the process and results closely.
This mixture is often more effective if one adds a small amount of liquid soap to the blend.
Milk
While there are no conclusive scientific studies to prove the effectiveness of milk, many people are using it to treat powder mildew. It is used mostly on roses, cucumbers, and squash. It is believed that it acts as an antiseptic. It is mixed in a ratio of one part milk to three parts water and sprayed onto the plant.
One of the first reports of this treatment was reported in 1999 by Wagner Bettiol, a Brazilian scientist. Other tests were conducted by Peter Crisp, a researcher from Australia. The results, in both cases, were positive.
We are by no means saying that this solution prevents or treats powdery mildew but there are many people that swear by it.
Mouthwash
Another unusual and controversial treatment is mouthwash. It is mixed in the same ratio as milk, one part mouthwash to 3 parts water, and needs to be sprayed regularly.
Mouthwash is designed to kill germs safely and appears to be effective on the spores of powdery mildew. It could have a negative effect on new growth so be careful with this method and keep a close eye on the plant.
Garlic
Another common home remedy for many plant issues is garlic and it can be effective against powdery mildew. To create this mix, blend two or three garlic bulbs in a quart (950 ml) of water, and add a small amount (a few drops) of liquid soap.
Strain the solution to leave only the liquid and cool in a refrigerator. Use one part of this concentrate to 10 parts of water and spray the plant. If the fungus has already started to spread, increase the concentration.
Apple cider vinegar
This has been used to protect against and treat powdery mildew for many years. Mix in a ratio of 2 tablespoons of the vinegar to a quart (950 ml) water and spray the plant thoroughly. Spray frequently and observe the plant to ensure it is working.
Compost tea
Another popular antifungal is compost tea. It is relatively easy to make but you can buy commercial kits that will help with the process. The tea takes a bit of time to create but goes a long way. It is completely safe, effective against powdery mildew, and offers other benefits to the plants.
Oils
These are used in many commercial organic products but can also be made at home. Oil such a canola oil works well but soap needs to be added to emulsify the mixture. Use about 3 tablespoons of oil, a quarter-teaspoon of soap (liquid dish-washing soap is fine) to a quart (950 ml) of water.
Neem oil can be used in the same way and also protects the plant from other pests and diseases. Other oils used by some growers and gardeners include rosemary oil or mint oil.
Commercial Organic Fungicides to treat powdery mildew
Here, you will pay a bit more but there are many great products on the market that are safe and effective.
It is always best to use organic solutions where possible as they are effective against unwanted problems and diseases without harming beneficial organisms, insects, birds, and other aspects of the delicate balance in your garden ecosystem.
The better products have been tried and tested and are safe to use. This is particularly important for use on fruits and vegetables.
Preventative (protectant) fungicides are usually used (as the names suggests) to prevent the appearance of fungal infection. If you catch the powdery mildew early enough and it has not multiplied prolifically, these products should help.
Ingredients to look out for include neem oil, lime-sulfur, sulfur, and potassium bicarbonate.
If the infection has multiplied and advanced you will need an eradicant fungicide.
Bacteria solutions
Both Bacillus pumilis and Bacillus subtilis are bacteria that prevent and treat powdery mildew. They also protect against other diseases.
Popular brands include Sonata (mainly used for roses), Rhapsody (popular with commercial growers) and Serenade which is the main option found at garden centers for home use.
Antitranspirants
These sprays are designed to reduce plant water loss (transpiration). They are often used on cut flowers and Christmas trees as well as shrubs that have been transplanted.
They stop the plant from drying out but can also be effective against powdery mildew. They are also beneficial for plants with blackspot and downy mildew.
The two most common brands on the market are Wilt Pruf and Vapor Guard. While these sprays are natural and safe they can reduce essential photosynthesis. Only use them when conditions are sunny and apply when new growth appears.
Air purification
For plants grown indoors, there are commercial air purification systems that reduce the risk and spread of powdery mildew. This is especially important when grow lights are used. Fans are often used with the lights to disperse the heat but this also helps to spread airborne pathogens.
Air purification systems “clean” the air and destroy powdery mildew spores as well as many other harmful pathogens.
Chemical fungicides (protectant or contact fungicides)
Sometimes a chemical solution is best. It can also be used in conjunction with other solutions we have discussed.
The most common chemical treatments for powdery mildew contain propiconazole, triadimefon, myclobutanil, hexaconazole, or penconazole. Sometimes these are used in combination.
Your local garden center should have a range of products specifically designed to combat fungal infections and most should be effective on powdery mildew.
Most general-purpose fungal sprays should be effective but as we will discuss, it is important to not always use the same ones.
Strobilurin Fungicides
These are systemic fungicides, part of the FRAC group 11 fungicides. They are effective against a range of pathogens and fungi. There is a range of options available. They work by preventing respiration in fungi.
Some popular brands and the active ingredients include:
- Flint – trifloxystrobin
- Cabrio – pyraclostrobin
- Quadris – azoxystrobin
- Quadris Top – azoxystrobin + difenoconazole, 11 + 3
- Quadris Opti -azoxystrobin + chlorothalonil, 11 + M5
- Pristine – pyraclostrobin + boscalid, 11 + 7
- Quilt – azoxystrobin + propiconazole, 11 + 3
You will note that some of the products are used in a combination of ingredients. What is important to note is that in many cases the fungi can develop a resistance to the chemicals.
It is necessary to use a range of fungicides to avoid this. Alternate the chemicals used to prevent fungicide resistance.
Other commercial treatments for powdery mildew:
SuffOil-X is another option. It needs to be sprayed regularly for prevention, control, and removal. Do not apply when it is extremely hot and bright as it could burn the plants.
Monterey Complete Disease Control and Monterey Bi-Carb Fungicide are other options.
For large applications, you can use MilStop.
How to prevent powdery mildew
Once you have this disease on your plants it can and will spread rapidly. The best measure is always to defend against it and prevent it before it starts. If your plants do become infected, you need to ensure that it is treated and removed quickly so that it does not spread to other plants.
Remember that spores can remain dormant for a few years so you need to prevent against reinfection down the line.
Plant powdery mildew resistant plants
While many plants are susceptible to the disease, certain varieties have been bred or are naturally more resilient to the disease. This is especially important in climates where the disease is more common.
By using these plants you reduce the risk of infection and the spread of this fungal disease.
Even some of the most susceptible plants, including squash, melons, and cucumbers, have strains that are all but immune to powdery mildew. With a bit of research, you can find the strain that is best suited to your environment.
If you are experiencing regular problems with powdery mildew it is important to research and find plants that are more resilient to the disease.
If you find that certain plants or crops are particularly susceptible to powdery mildew it is probably best to remove these plants altogether and plant something else.
There is no point fighting an ongoing battle. It will only put your other plants at greater risk.
Remove infected plants as soon as possible
The spores are light and travel quickly. If powdery mildew is noticed the best bet is to remove all infected plants immediately.
If this is not possible or viable, remove heavily infected leaves, treat, and monitor.
Do not discard nearby or compost the infected plants as this will only worsen the problem. Bag and discard or burn the plants.
Water well from above
One of the conditions that the disease thrives in is hot and particularly dry conditions. Without overwatering the plants, give them sufficient water so that they are not distressed. Water from above for maximum effect.
Plant in the sun
While this cannot be done with all plants it is possible with most of the more susceptible plants. Powdery mildew prefers shade so it stands to reason that plants in the sun have a better chance of not being infected.
You need to prune carefully around plants so that they get enough light and air to reduce the risk of powdery mildew. This pruning also reduces humidity which the disease thrives on.
Ensure there is good air circulation
Poor circulation around plants leads to many problems and can contribute to an increase in powdery mildew. As mentioned above prune and clear the area around the plant to improve the airflow. Keep some space between plants so that they are not overcrowded.
Do not over-fertilize
It is best to use a slow-release type fertilizer to encourage natural growth. Powdery mildew is likely to occur on new growth so rapid growth could make the problem worse.
Mulch
Applying a decent layer of compost (quality organic compost) after preparation is a good practice. This will cover any dormant spores that might be present in the soil and prevent them from getting to the plant.
If you practice all of these precautions and preventative measures it is unlikely that you will need to resort to any organic or chemical remedies. A healthy protected plant in the correct environment is not likely to be affected by powdery mildew.
Which plants are particularly at risk of powdery mildew?
As there are so many varieties of powdery mildew it affects a wind range of plants.
Flowers at risk include roses, sunflowers, dahlias, zinnias, begonias, and chrysanthemums. Other plants at risk include hydrangea, phlox, gerbera daisy, and verbena.
Vegetables and fruit that are particularly susceptible include tomatoes, peppers, cucumbers, potatoes, peas, beans, eggplants, melons, squash, pumpkins, grapes, parsley, and lettuce. Many fruit trees are also at risk.
Marijuana is now a major legal crop in many parts of the world and there are also many enthusiastic home growers. Powdery mildew is a major threat to this plant especially when grown indoors.
This list is not exhaustive and many other plants are susceptible. It is therefore important to keep a careful eye on all plants.
Frequently asked questions about powdery mildew
When do I need to worry about powdery mildew?
One should always be on the lookout for pests and disease but when the weather is particularly hot and dry, you want to inspect regularly for signs of powdery mildew. It can occur overnight and spread rapidly. The sooner you identify and treat it, the easier it is to eradicate.
Is it difficult to see and identify powdery mildew?
No, one thing about this fungal infection is that it is easy to spot even in its early stages. The white to gray spots are fairly obvious and can be seen with the naked eye.
Are my plants safe from powdery mildew in a greenhouse?
Unfortunately, they are not. A greenhouse, in fact, is an ideal breeding ground for the disease and extra care should be taken in preventative measures. One should always be on the lookout for any sign of the infection and take fast and decisive action if it occurs.
Does all powdery mildew look the same?
The answer is no. While the vast majority of cases present with white/gray spots that start on the leaves there are other variants of the disease that look different.
A good example is Leveillula taurica. This forms as yellow patches and is normally found on tomatoes and artichokes. The patterns and behavior are the same but the color is different.
Can I not just ignore powdery mildew?
Just because it does not kill the plants is no reason to not be concerned. The disease literally sucks the nutrients out of plants and if left untreated it can spread rapidly.
It makes the plants look unpleasant and unhealthy. In flowering plants you will have fewer flowers and the quality will be poor and possibly misshapen. In fruit and vegetables the yield will be significantly lower and of a poor quality size and the taste will not be great.
Is powdery mildew harmful to humans?
The fungi are not harmful to humans. If you touch it or eat a fruit or vegetable that has powdery mildew it will not do you any harm. The only harm is to your attractive plants and your fruit and vegetable yields.
What is the difference between powdery mildew and downy mildew?
Both are fungal diseases but there are distinct differences. For instance, downy mildew is more prevalent on the underside of the leaves while powdery mildew is usually more noticeable on top of the leaves. Also, the spores are smaller and more difficult to notice. The color is also different. Downy mildew is darker, red to purple or brown in color.
Downy mildew preys on similar plants and is also common but is more common in cooler climates or seasons. It also likes high humidity.
Is powdery mildew the same as sooty mold?
Not at all. While they are both caused by fungi they are completely different. Sooty mold, as the name suggests, is dark in color. The leaves turn black and start to die off. The fungus is prevalent on plants with an insect infestation. They secrete honeydew which is what attracts the sooty mold.
Final thoughts
Powdery mildew is a serious fungal infection that is extremely common all over the world. The good news is that it seldom, if ever, kills the plants.
That is not to say it should not be taken seriously. It is a serious plant disease that needs to be treated quickly and effectively.
Knowing how to identify it is critical. Prevention, as always, is better than cure. Take the necessary precautions to reduce the risk of infection. Inspect plants regularly to see if any plants have been infected.
If noticed, it should be treated correctly and regularly. Keep a very close eye on plants to ensure the treatment is working and do what is necessary to prevent the spread or future infection of plants.
When the rights steps are followed for prevention and treatment, powdery mildew is nothing more than an irritation. Left untreated it can be disastrous. Do not think that just because it does not kill plants it is not a major threat.
Look after your plants, treat them well, and avoid this dreaded fungal disease.
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Read the Article: Best Potting Mix for Vegetables
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.
About me
This is me and my Chinese Money Plant. Taking care of houseplants and gardening are my greatest passions. I am constantly looking for new houseplants to gradually transform my apartment into an urban jungle and grow veggies in my garden year-round.
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All you need to know and then some take your pick and have a great season .
ok well perhaps there has been a misunderstanding. What we want to achieve is a protocol to exterminate powdery mildew. I’m talking boom dead it never comes back. The powdery mildew protocol I recommend does that. Unfortunately the information you posted has no protocol for the elimination of the parasite, so it’s not useful. You never came up with an elimination protocol either, so I would suggest that method does not work.
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I did mix according to directions and spray in the evenings . They also make a cleaner that might be useful in removing failed remedies lol . I do a soil drench also but that’s just me I think I’ll back out of this and let everyone find there own way . Sulfur works great but not on buds I posted a link several times on the product I use read it . It has all you need to know about the product take it or leave it .
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I did read it, and I read everything you posted. Unfortunately, there was no information regarding the eradication of the mildew. So I will disregard it as time wasting. Anyone reading this, know that I will stake my reputation on the fact the mildew extermination protocol I describe will end your problems once and for all. I will tell you exactly how to exterminate the mildew and try and help you recover from fear, using knowledge. The more you know, GI Joe.
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