POWDERY MILDEW - 6 weeks flowering

milk doesn't consistently work, so guess what? it probably doesn't do much. At best it changes pH, which is same hope/prayer of using baking soda. amputate any parts that show the disease. by the time you can see it easily it's already spreading spores around, but being gentle about it or wrapping it before agitating can't hurt. but dynamics of a grow area involve circulation fans, so it has already potentially started spreading around with 5-7 days of infection -- not when you can see it, but actual infection. low RH prmotes faster spread. high RH promotes faster reproduction. Damned if you do, damned if you don't. I'd keep your VPD in check but don't think chanign pH will do anything. It's good to avoid exctreme RH on either end. all the little concoctions you can google do not work. nothing will rid your plant of wpm if it is systemic. Clean the surface, sure, but the fungi creates a mycelium network underneath teh surface, and that's going to re-grow on surface eventually. preventative measures are key. using horticultural oil (like neem) can coat the leaves and make it lower probability that a spore can latch on successfully. Keep area clean of dead plant material -- don't leave dead leaves and other rotting material around. if it's fairly warm during light cycle and operating at 45-55 RH give or take, you'd be suprised how high the dewpoint is. Make sure you are not hitting dew point when lights go out and it cools down. RH skyrockets to 100 % more quickly than you probably perceive. I have a dehum, so i never worried about it, but i was probably getting some dew on my leaves which only invites WPM and other microbes. if it happens each night even for a few minutes, it's promoting microbial growth. I've had wpm issues for a while. one of the recent changes that lead to a 100% clean run was keeping it slightly warmer at night. Reference a dewpoint calculator. type in your peak operating temps and RH while lights are on. What is the dewpoint? keep night time temps above that --- at least until any dehumidifier can work it's magic and get the skyrocketing RH undercontrol. i also elevated my P ppm, which supposedly makes a plant more robust to infection... that's what the leaf symptom chart says, lol. https://extension.psu.edu/powdery-mildew -- shit url changed.. was a rundown on basics of it.. thinkgs to now -- it is supposedly species specific, so WPM from a different plant in your garden should stay relegated to that same species. it supposedly does not overwinter, so a few months of time betweem grpws can greatly help avoid it -- (anecdotal - i had plants that looked like someone doused with fake xmas snow, next cycle - zero problems. not even a colony formed - so not likely an overwintering trait). Get real info from places that perform studies, like a university. This info will be far more reliable than forums and "grow questions" on GD. uvB is showing promise with vineyards -- https://news.cornell.edu/stories/2019/05/uv-light-may-be-ripe-replace-chemicals-fungus-fight The cornell formula (see above 'concoctions') does not work. if it does anything it affect pH. It is named after a university but has absolutely nothign to do with any research or evidence-based reason to think it works well. Even real commercial grade fungicides are not very effective at treating a WPM infection -- and that's dangerous stuff at times... there is no real solution to this problem despite the numerous sources you can find proclaiming they can cure or beat WPM.. they are fucking liying and too low resolution to verify the claims anyway if only using human senses of sight/smell et al. Don't spray your plants with millk. you can even find people that believe in it arguing over whether you should use whole or skim milk... neither show consistent results, therefore an extremely weak correlation results. most likely just the pH change is the effective element and you can do that withtout spraying your plants with tsomethign that will rot and stink.. then the rot could be a vector for microbes too. I made this mistake when i was really, really desparate. don't spray your plants with milk. it's as false as thinking rain can make you sick. anecdotal wive's tale nonsense. play in the rain all you want.. bacteria and viruses cause sickness, not getting wet. Yet, many believe such a thing. many believe stress causes heart burn... not true, either. ppl beleive all sorts of things that are not true. So the best thing you can do is avoid the most receptive environment for WPM growth. if it shows up, make sure you aren't getting dew on yoru leaves at night. remove infected parts, immediately upon finding it. good circulation can help prevent it. horticultural oil can help prevent it / slow spread down. Nothing cures it. foliar sprays on wpm often just spreads it onto the stems. you end up with wpm under buds along stems which makes it even harder to find. this is a truly no-win situation. way the rate of spread vs time left and make a decision on harvest. sometimes a slightly early haravest may yield better than waiting another 5-7 days. That shit is going to double size of infection every week or so. if you find a spot, remove it and don't see anythign for weeks after, you can feel good about that. be happy you got lucky before it spread.

Short answer: It will always be on your plant. You can't truly beat powdery mildew, as it will always come back once it established itself. The best thing you can do is treat it and keep it under control until you harvest. Remove all the infected leaves and then start using an IPM that is directed at controlling Powdery mildew. Good luck.

Robert's is correct but I use homogenized milk at 60 parts water to 40 parts milk. I don't like copy and paste answers. The milk works, but you may need to repeat if you haven't lowered your humidity

50 50 mix milk and water to treat mildew. Then lower humidity.

Increase air flow, lower humidity, increase space between the plants and decrease the RH and Temperature swings in the room. You will need to totally remove the spots that have it, but when doing so taking a chance of it spreading it with every branch you touch. Here is a post that may help you. 5 Tips for Eliminating Powdery Mildew on Cannabis Crops - Greenhouse Grower 5 Tips for Eliminating Powdery Mildew on Cannabis Crops Welcome By Ryan Douglas, Ryan Douglas Cultivation LLCJune 10, 2021 Powdery Mildew in Cannabis Ryan Douglas Powdery Mildew in Cannabis; Photo: Ryan Douglas In the world of fungi, powdery mildew is unique, and controlling it can prove tricky for commercial cannabis growers. Unlike bud rot caused by Botrytis cinerea, powdery mildew can’t be stopped by simply drying out the atmosphere. Many growers think of powdery mildew as a dry mold because it can spread rapidly in environments with relatively low humidity levels. This is because the devil is in the details. Powdery mildew spores don’t require standing water to germinate, only brief periods of high humidity. Temporary environmental fluctuations are all that’s needed for spores to come to life, latch onto the leaf surface, and start sucking energy from the plant. Preventing the spread of powdery mildew must involve a multi-faceted approach that attacks the issue from several different angles. Consider these five tips to help keep your crop clean of this troublesome disease. Avoid Extreme Temperature Fluctuations Day and night temperatures should not fluctuate more than about 15°F. The optimal temperature range for cannabis production lies between 68°F and 85°F, but the tighter the variation, the less susceptible your crop will be to powdery mildew attacks. These fluctuations are one of the most significant contributing factors to disease infection for indoor grow operations. When lights shut off, temperatures can plummet for a short period of time. As temperatures drop, the air holds less water, so it is released into the environment. This can result in micro condensation and pockets of high humidity, setting the stage for spore germination. HVAC and dehumidification systems eventually catch up and stabilize the environment, but by then, spore germination has already occurred. Wall-mounted fans help to disperse the spores, and employees that brush up against the plants will inadvertently carry the spores to new spots in the grow room. Even though the day and night temperatures may be steady, a 45 to 60-minute period of extreme fluctuations can aggravate the onset of powdery mildew infection. Use Leaf Surface pH as a Weapon It may be impossible to eliminate powdery mildew spores from the environment, but at least growers can make it more difficult for infections to take hold. The success of powdery mildew closely depends on the pH of the leaf surface, so raising or lowering this value can disrupt its ability to become established in the crop. The application of products containing potassium bicarbonate will temporarily raise leaf surface pH, while products that contain sulfur will drop it. Although these products are approved for organic production, it is preferable not to use them on fully flowering plants. If you anticipate powdery mildew problems, consider using these products preventatively up to the second week of flower. Beyond this point, the application of these products could negatively affect the finished quality of your cannabis. Fight Nature with Nature Biofungicides are another organic method of preventing powdery mildew outbreaks. Products that contain Reynoutria sachalinensis use an extract of giant knotweed to trigger the plant’s natural defense mechanisms and produce disease-fighting biochemicals. This induced disease resistance is not systemic, meaning that only the treated area of the plant is protected. Still, it is translaminar, meaning that if sprayed on the top of the leaf surface, the bottom of the leaf will be protected as well. However, new plant growth is not protected, so the product must be reapplied on a seven- to 14-day schedule. Although biofungicides can be a powerful addition to a grower’s disease-fighting toolkit, make sure to verify that the use of fungicides — even organic ones — are permitted for use on your cannabis crop. Filter Out the Problem Most indoor cultivation sites do not circulate air between individual rooms, but even closed-loop ventilation systems can perpetuate powdery mildew outbreaks by dispersing spores throughout the grow room. Installing air filters with a MERV rating of 9 or higher can help capture mold spores and prevent them from being re-introduced into the cultivation area. Have your HVAC technician install these filters in the air handling system and be strict about cleaning or replacing them on a set schedule. With Severe Infestations, Cut Your Losses, Not the Leaves When powdery mildew is first spotted in a crop, it makes sense to remove the affected leaves. But if none of the previous four recommendations are followed, it’s unlikely that an outbreak will improve through leaf removal alone. With heavy infestations, removing leaves can actually make the problem worse. As workers pluck leaves, they inevitably cover their hands with spores and spread them through the crop every time they touch a plant. With severe infestations, this activity spreads as many spores as it removes. Furthermore, if the defoliation is extreme, the mildew will spread to the only part of the plant that remains to be infected — the flowers. Maintaining a crop that is heavily infested with powdery mildew will place the rest of the cultivation facility at risk. Sometimes it’s better to scrap the crop instead of providing life support until harvest day. Cutting down a damaged crop hurts, but infecting the entire facility will prove much more painful. As with any disease, prevention is key. Since cannabis cultivators can’t rely on conventional fungicides to protect their crops, growers must be creative as they fight the good fight. Goodluck growmie