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Powdery Mildew

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Powdery Mildew

Mountaingirl 35 Replies 44,673 Views
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Mountaingirl

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#1
Has anyone ever used colloidal shield to treat pm systemically, I got it bad and their in flower. I've already tried nem oil, and baking soda, and pmt made by cx. I'm bought ready to trash them and start over but was told the colloidal shield works well, so were giving it one more week. I have the under current system. Any suggestions?
 
#2
Im sorry,eagle 20 I heard works somewhat but powdery mildew is like herpes once your plant has it any little stress and BAM it will come right back,you could finish it and make hash or bho but its all up to you,you need clean genetics that has never been exposed to powdery mildew
 
#3
I would NOT use E20 in flower. That's me. The physical barriers and pH adjusters should be working for you, at least for controlling the PM fruiting bodies. I would look less to chemistry and more towards husbandry.

Consider getting and using a sulfur vaporizer. Initial cost isn't too bad. If you get the Ecoplus, it comes with absolutely SUCK-ASS directions.
 
#5
Run your room up to 95 to 100 degrees for 1 to 1 1/2 hours that will kill the PM. Can you find a product called Mighty Wash, it works also. PM is very reactive to pH so here are a couple other things to try.

What week of flowering are you in?

Part 1

How to Beat Powdery Mildew
BY URBAN GARDEN MAGAZINE ⋅ AUGUST 6, 2009 ⋅

If there’s one grower’s gripe we hear lots about at Urban Garden HQ it’s Powdery Mildew. So we asked our heavyweight in the pest control department, Zorro Torro, to lend some expert advice on what this nasty stuff is, what damage it causes your plants, and, most importantly, how to beat the crap out of it!
You’ll know powdery mildew has paid your plants a visit when it looks lot like confectioners’ sugar has been sprinkled on the plant leaves. At first it may be hard to spot as it might appear on just a small portion of the leaf appearing as an irregular circle. But it quickly spreads and soon appears on the surrounding vegetation. Soon the entire leaf is covered and at the same time colonies develop on the surrounding vegetation and in other areas of the garden.
So how does it all start? Well, the plant becomes infected when an airborne spore, or conidia, lands on a leaf and germinates. It soon grows a guide tube that attaches tightly to the leaf. Then it pierces the plant cell wall and membrane and inserts a hollow tube that sucks up plant nutrients, weakening the leaf and slowing growth. Within a week the fungus produces tiny mushroom stalks that release millions of spores, ready to infect more leaf surfaces. The fungus also produces a secondary spore, which over-winters outdoors and may also hide in a greenhouse or indoor garden even after the crop has been harvested.
Powdery mildew is most likely to attack the young leaves, up to two or three weeks old.
A dozen or so different fungus fall under the heading of Powdery Mildew, but two different fungus species are the most likely culprits. L. taurica, tends to attack warmer gardens. It prefers a temperature of about 77 °F (25 °C). S. macularisprefers a cooler temperature; however, the more virulent stain found in indoor gardens today has adapted to tolerate more heat. Both strains thrive in moderate humidity and are not injured by water. Their conidia can live in water for short periods and are mobile in it. However, strong water sprays do destroy some conidia.
CULTURAL CONTROL
Heat
Powdery mildew is sensitive to heat. Neither species will grow at 90 °F (32 °C). and will quickly perish when above 100 ° F (38 °C).
To get a complete kill maintain the temperature for an hour. This may not be a feasible option in most indoor gardens for several reasons. The first is that it may be difficult to heat the space to such a high temperature. The second is that even a single peak of 100 ° F (38 °C) affects the growth of plants. Vegetative plants with flowers or fruits in mid stage growth (weeks 3-7) may stretch a little from the experience. The heat treatment has relatively little effect on first and second week flowers or flowers nearing maturity.
You can minimize heat’s impact on plants in several ways. Heat the garden at the end of the day, as the lights are turned off. Since the plants are not photosynthesizing, they have lower water needs.
If the plants are being grown hydroponically, lower the temperature of the water to 60 degrees. Keeping the roots cool will help the upper plant parts beat the heat. It’s not difficult to do this, even if you don’t have a water chiller. Just add ice to the reservoir or flow through system. Roots of plants growing in soil can also be cooled using thermal ice packs at the base of the stem.
The heat treatment should kill off most of the fungus and its spores. The chances are there will still be some fungal re-growth. These can be eliminated using spot treatments.
Pruning
If one particular plant seems to be infected with a few tiny white spots on a few of its leaves, get a bag large enough to drop the leaves into and then cut them off into the bag. Remove the bag from the room. This prevents spores, the white powder on top of the leaves, from becoming airborne while being removed. Remember to wash your hands and clean the scissors or knife with soap and water, hydrogen peroxide, alcohol or bleach. Spray the plant with one of the sprays listed below after pruning to prevent re-infection and encourage healing.
If, you notice a re-infection a few days later, there is a good chance that this plant is very susceptible to powdery mildew and presents a good location for the infection to start and spread from. The plant should be removed immediately by placing a bag over it and removing it from the space. Then the space should be sprayed with one of the sprays listed below.
ORGANIC and IPM CONTROL
Here are some sprays that you can use to control the powdery mildew in your crop. All of these are safe to use for herb or for edible crops. Sprays are washed away by water, including rain.
Cinnamon Oil and Tea
Cinnamon is an effective destroyer of powdery mildew, with an effectiveness rate of 50-70%. It won’t kill it completely but it will keep it in check somewhat. It also potentiates other suppressive sprays so it is good to use in combination. To make your own, boil water, turn off the heat and add one ounce of ground cinnamon to one and a half pints water. Let the tea cool to room temperature. Add half a pint of 100 proof grain alcohol or rubbing alcohol and let sit. Strain the cinnamon. The spray is ready to use. A faster method is to add 2 teaspoons cinnamon oil to one pint of water and a dash of castile soap. Other herbs are also fungicidal. Clove, rosemary, and wintergreen oils are used in some botanical fungicides. The solution should consist of no more than 2% oil.
Garlic
Garlic is antifungal and anti-bacterial and has several pathways for destroying fungi including its high sulfur content. It can also be added to other anti-fungal sprays. Several garlic sprays are available commercially.
A homemade formula: Soak three ounces of crushed garlic in one ounce of neem or sesame oil and 100 proof or higher drinking alcohol or 70% or higher rubbing alcohol for a day or two. Strain. Then soak the garlic in a cup of water for a day. Strain. Mix the oil/alcohol, soaked water and 1 tablespoon liquid castile soap in a gallon container. Then fill with water and shake. The formula is ready to use.
A simpler brew consists of a teaspoon of garlic oil in a pint of water. To keep the oil and water mixed add a 1/8teaspoon of soap. Use garlic as a vaccination. Spray on new growth before there is a sign of infection.
Garlic is a general purpose insecticide as well as fungicide, so it should be used with caution on outdoor plants. It kills beneficial insects as well as plant pests.
Hydrogen Peroxide
Hydrogen peroxide (hp) is a contact fungicide that leaves no residue. It is an oxidized product of water and has an extra oxygen atom that is slightly negatively charged. When it comes in contact with the fungi the oxygen atoms attach to molecules on the cell walls, oxidizing or “burning” them.
Household hp sold in drug stores has a concentration of 3%. Garden shops sell 10% hp. Zerotol® contains 27% hydrogen peroxide and an unstated amount of peroxyacetic acid. Together they have a more potent chemistry than hp, with an activity of about 40% hp. It is considered hazardous because it can cause skin burn similar to that caused by concentrated acids.
To treat plants with drug store grade 3% hp use 4 1/2 tablespoons and fill to make a pint of solution, or a quart of hp to 3 quarts of water. With horticultural grade 10% hp use about 4 teaspoons per pint, 5 ounces per gallon. With Zerotol® use about 1 teaspoon per pint, 2 1/2 tablespoons per gallon.
 
#6
Part 2

Limonene
Limonene is refined from the oil of citrus rinds. It has a pleasant citrus odor and is the active ingredient in many of the new cleaning products. It also has fungicidal qualities. I’ve used pure diluted limonene and it controlled powdery mildew, but did not eradicate it. Perhaps a higher concentration would have been more successful. Start using 0.5-1% limonene in water 1/2-1 teaspoon per pint.
Milk
Milk kills powdery mildew so well that both home and commercial rose growers all over the world have adopted it for their fungicidal sprays. Use one part milk to nine parts water. I’ve only used 1% milk, but other recipes call for either whole or skim milk and use up to 1 part in 5 milk. Some recipes add garlic or cinnamon to the mix. When using more than 30% milk, a benign mold is reported to grow on top of the leaves. Use a milk spray at the first sign of infection then protect the new growth weekly.
Messenger®
Messenger’s active ingredient is a naturally occurring protein called harpin that stimulates the plant’s own natural defense system. It has been proven to promote more vigorous hardier plants that are more resistant to disease and have increased yields. It is used to prevent infection and decrease its virulence
Neem Oil
Neem oil is pressed from the seed of the neem tree (Azadirachta indica), native to Southeast Asia, but now cultivated worldwide. Neem oil has low mammalian toxicity. It degrades rapidly once it is applied so it is safe for the environment including non-target species and beneficial insects.
Neem oil protects plants with its fungicidal properties: it disrupts the organism’s metabolism on contact, forms a barrier between the plant and the invading fungus, and it inhibits spore germination. It has translinear action, that is, it is absorbed by the leaf and moves around using the leaf’s circulatory system – it can also be used as a systemic. When it is applied to the irrigation water it is absorbed by the roots and delivered throughout the plant. Adding a 0.5% solution, about 1 teaspoon per quart, to the irrigation water will protect the plant from infection.
Neem oil is best used before the plant or the garden exhibits a major infection. By using it before powdery mildew appears, it prevents the spores from germinating. It should not be used on buds or flowers.
Oil Spray
Growers have used different oil sprays to prevent and cure fungal infections. Until recently most horticultural oil sprays were made from petroleum distillates. However, most organic growers have switched to using botanical oils. Aside from the safety factor botanicals such as cottonseed, jojoba, neem and sesame oils have fungicidal properties. They can be used in combination with other spray ingredients listed here. The oils are mixed at about 1-2% concentrations. A 1% solution is about a teaspoon per pint or 3 tablespoons per gallon. Add castile soap to help the ingredients mix. Oil sprays should only be used on the leaves, not the buds or flowers. Use weekly on new growth.
pH Up
pH-Up is a generic term for alkaline pH adjustors, used to increase water pH in indoor gardens. They come as either a powder or liquid. Its active ingredient is usually lye (KOH) or potash (K2CO3).
Fungi require an acidic environment to grow and die in alkaline environments. Changing the leaf surface environment from acidic to alkaline clears up the infection. An alkaline solution with a pH of 8 will make the environment inhospitable for the fungus and will stop its growth. This is one of the simplest means of controlling the fungus. It can be used on critically infected plants.
Potassium/Sodium Bicarbonate
Potassium bicarbonate (KHCO3) and Sodium bicarbonate (NaHCO3) are wettable powders that change the pH of the leaf surface toward alkaline. Another reaction takes place; the fungus cell wall actually bursts in the presence of bicarbonate. Potassium is one of the macro-nutrients used by plants and therefore is preferred over sodium, as sodium can build up in the soil. Sodium bicarbonate can be found in your kitchen (baking soda), so some prefer it for ease of obtaining. Both are more effective when used with an oil and spreader such as castile soap. They can be used to cure bad infections and prevents new ones.
Use one teaspoon of bicarbonate powder, a teaspoon of oil and a few drops of castile soap in a pint of water, or 3 tablespoons each potassium bicarbonate and oil and a half teaspoon soap in a gallon of water. Spray on new growth.
Serenade® and Sonata®
Serenade® and Sonata® are composed of different bacteria. They use different pathways to stop mycellial growth. They are considered totally safe to humans and animals since the bacteria attack only fungi. Watch out if you are a mushroom, otherwise you are safe. The two bacteria work well together.
They are easy to use, quite safe and effective.
Sulfur
Sulfur has been used to control powdery mildew for centuries. Sulfur sprays can be used indoors but they are not popular because of residue that remains on the plant. In greenhouses gardeners use sulfur vaporizers that heat elemental sulfur to the point of vaporization. The sulfur condenses on all surfaces including the leaves. A fine deposit of very low pH sulfur granules covers the leaf surfaces. The low pH environment inhibits fungal growth. The heaters use a 60 watt light bulb to heat sulfur which is held in a container above the light. The bulb supplies enough heat to evaporate the sulfur, but not enough for it to ignite. The problem with vaporizers is that they also leave a fine sulfur film on the leaves and flowers.
Active mildew: 7 to 8 hours per night 1 to 2 times a week.
Preventative maintenance: 4 to 5 hours once a week
Vinegar
Apple cider vinegar is toxic to powdery mildew because of its high acidity (low pH). Use it at the rate of 1 tablespoon per quart of water several times a week . Some gardeners recommend alternating using vinegar with potassium bicarbonate and milk.
PREVENTION
· Isolate all new plants in a separate area where they can’t infect other plants.
· Filter incoming air to prevent spores from entering the room in the airstream.
· Install a germicidal UVC light, like the ones used in food handling areas. The light is fatal to all airborne organisms passing through the appliance. This will kill powdery mildew spores that are airborne.
· Spray the leaves with neem oil weekly. Neem oil presents both a physical barrier and a chemical deterrent.
· Cinnamon oil and cinnamon tea can also be sprayed as a powdery mildew preventative. If you are using cinnamon oil use 1 part oil to 200 parts water. (1 teaspoon oil in a liter of water.)


Thank you Urban Garden mag.

http://urbangardenmagazine.com/2009/08/how-to-beat-powdery-mildew-in-hydroponics/
 
#7
If you are at wits end...and ready to go the chem route...I would use something like E20. Like Seamaiden said though...not in flower. E20 should be used in Veg...cuz it has a residual effect of like 45 days. I would spray moms...wait 10-14 days spray again...wait a few weeks get them healthy as they will stress...then take cuts to reset moms. Just remember to keep in mind the residual effect! E20 will battle systemically....if done right it would end your problems...but like I said there is residual effects.

As for flowering plants....I believe there are homemade milk sprays that can contain it to finish if you choose that route...I would wipe out flower room after harvest...clean with E20...then clean with a bleach mix.

I will say this....E20 is not for regular spraying...it is to solve a problem. Coming up with a good spraying routine with some organics would be a long term solution...but you have to stick to your spray routine...like it is maintenance. Maybe come up with an isolation site for new incoming plants...don't go near other infected gardens...since you have it...you might wanna think about how to prevent it in the future...

Proper dosage is key also...

my 2 cents.....
 
#8
Thank you all so much for the help. Unfortunately I think it is just to late. The pm is so bad it looks like the entire room has been dipped in powdered sugar, it's horrible. I'm going to bag it all in plastic bags, remove it from the room and bleach the entire area. Walls, floor, etc. I'm trying to find what strain I should do next. I'm going to get clones this weekend and I want a sativa with high Cbd and good yields. Any ideas would be awesome!!
 
#9
Oh... fuck. Yeah... I can't make clone recommendations, but I would use isopropyl alcohol after the bleach, just spray it on and let it dry. And should it continue to pop up (expect that to occur until you have a handle on environmental and other husbandry issues), I completely forgot that milk is a proven treatment for powdery mildew. It's also effective for preventing spread of viruses in the greenhouse. I'll attach some information here for you.



This is with regard to milk in organic gardening:

This is actually a pdf, but I went for the cached version. Linda Chalker-Scott, controversial if not at least somewhat well educated. The Myth of Milk and Roses
 

Attachments

#10
I would skip the bleach, smell and residual.
Alcohol sprayed in a room = BOOM if any flame

H2O2 spray and let dry. Kills PM on contact. No smell and no BOOM.

IMHO

Seamaiden, not knocking alcohol as it works, but some growers are not that smart and lighting a joint while you work could produce bad results, funny as hell but dangerous.

Love Linda and have lots of her reports and papers. She sure has passion.
 
#11
While it's in an aerosol form it may be dangerous, but I use it very often and usually have a joint going and haven't ever had a problem. That's using it straight. It's no more dangerous than removing nail polish while smoking a joint, IME. ;)

H2O2 is another option, too, of course. There are many, but I would use more than one since what she described sounded pretty bad.
 
#12
When your room is cleaned set off a fungaflor bomb. I'd check into your environment controls, something's not right. I'd guess there are some big swings in your RH and temps from day to night.
 
#13
I would spray your current crop daily with potassium bicarb; spray them hard to knock the stuff physically down. This will wash your plants and possibly save your current grow. Obviously, run the room's RH a bit lower to help the buds dry, and increase the interval after the first few days, and try to discontinue altogether as the plants enter their final week before chop.

Between crops, spray your ROOM with Eagle 20 SC, including floor, outside of buckets, corners, closets, everything. Spray the plants you plan to move into the room before the trip with your choice of foliar sprays, I would suggest Cap's foliar pak properly brewed up and sprayed on regularly. Now, you've killed it on your new plants and you've killed the room, and that will at least give you a leg up on it.
 
#14
One final piece of powdery mildew advice; run fans on your plants to circulate air around the leaves and buds. Don't blast them, but keep the leaves gently dancing. This has all kinds of benefits, including helping the plant manage its own environment and increasing resistance to invaders like powdery mildew.
 
#15
Mountaingirl said:
Thank you all so much for the help. Unfortunately I think it is just to late. The pm is so bad it looks like the entire room has been dipped in powdered sugar, it's horrible. I'm going to bag it all in plastic bags, remove it from the room and bleach the entire area. Walls, floor, etc. I'm trying to find what strain I should do next. I'm going to get clones this weekend and I want a sativa with high Cbd and good yields. Any ideas would be awesome!!
Click to expand...

I can recommend Dairy Queen as high CBD, tho it isn't a straight sativa, it's a hybrid.
 
#16
sourthern california has a killer powdery mildew,strain raising the heat to 100 will not do anything to this super strain I still have a HIgh times magazine with a big print up about it,let me see if I can find it but it aint going away if you got this strain of pm its like herpees it thier for life
 
#19
socalpunx said:
sourthern california has a killer powdery mildew,strain raising the heat to 100 will not do anything to this super strain I still have a HIgh times magazine with a big print up about it,let me see if I can find it but it aint going away if you got this strain of pm its like herpees it thier for life
Click to expand...
 
#20
Thanks for replying. Have you been able to find that article I would be interested to see that. Even my few outdoor plants are now showing signs of it. And my indoor moms that are in a completely separate area. The temp and rh are 73 temp/40 rh 76 on plants when lights on
 
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