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AbuKeif

Defguard for bud rot/PM?

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Hey OpenGrowers,

I'm doing my first outdoor-ish run in a small greenhouse this year, and everything had been going wonderfully until last Friday, when I spotted a little bit of mold on one of my girls--looked like the beginning of bud rot.  When I was working indoors, I never had any difficulties with mold, but now that temps are starting to drop into 50F range at night, I guess I'm about to experience some of the classic outdoor issues. 

The very friendly folks at my local grow shop recommended Defguard as a deterrent for both botrytis and powdery mildew, but there seems to be very little information about it online besides the info supplied by General Hydroponics. My non-scientific understanding is that it's basically beneficial bacteria that colonize the plants' micro-biomes in a way that leaves detrimental molds with less of a chance to establish themselves. 

The grow-shop advice-givers suggested that it was safe to use all the way through flower, but I'm having difficulty finding any reviews online that might confirm this--can anyone share some opinions or experience regarding this product?  I'm particularly interested in opinions on safety for human consumption, and hearing about whether it might affect the flavor of the bud if applied this late in bloom.

And yes, before someone says it, I now understand that it would have been ideal to use this stuff (or another similar organic fungicide) all through veg and into the first weeks of bloom in order to create a healthy bacterial community and minimize the chance of mold late in the season... live and learn!  I now know what I'll be doing next year.

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I state that I am not a very expert, but according to my experience with these plants and others, I am a gardener,  instead of spraying the product on the plant it is perhaps better to find a product to give in the soil, a systemic fungicide would be ideal, on the product should be written the time of decadence of the product that is to say how many days before consuming "the vegetable" you have to stop the administration ... immediately remove the part of the plant affected by the mold otherwise it passes from plant to plant and is not good ..... I hope I helped you ... bye 

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Hi Haze--

Thank you for your input!  Indeed, if I could start my greenhouse grow again, I think I would have put more effort into cultivating a rich microdiversity in the soil earlier in the season.  Organic methods are important to me, so I would be interested to hear any suggestions you (and our fellow growers) have for organic systemic fungicides that could be applied to soil.  I have removed the small amount of mold that I saw on one plant (out of nine), and will definitely be very vigilant about checking the plants every day until harvest!

An aside: the only plant that I noticed was being affected was a very indica-looking wild-pollinated Lebanese landrace.  I have a slightly taller, wispier Lebanese plant as well--that one and all of the other "name-brand" strains don't seem to have been bothered yet!  Maybe it's that they're hybrids with some sativa lineage and mold resistance, or maybe it's that the Leb plant had larger, denser buds earlier than all of the others...?  I had been hoping that landrace vigor would result in fewer disease problems, but that seems not to have been the case.

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I wish we had a good solution for this, that was not harmful to health. The mighty ugly, and do not use Eagle 20 gets rid of it. We need something that does the trick like that, but is not dangerous to use.

Many use sulfur for PM. I would think would be much less chance of bud rot if you have a really nice steady air flow, and plenty of room between plants. Do you have a way of putting an air source on the plants?

Cover with plastic when it is suppose to rain, remove when it stops raining, make a tent like if needed, make sure the drip line goes beyond the plants. Shake plants of rain.

Remove any plants in the area that are prone to PM. If PM present, bag plants before removing. IF dealing with plants with PM< remove cloths, shoes, all, shower, before dealing with the ladies.

Considering researching for next year, plants that are resistant to mold.

I believe Jorge Cervantes has a video out about cleaning up PM with peroxide water. I did that many years ago, yes it got rid of it, and I rinsed it several times, in stages, the majority of the mold, second container rinse to get the remainder off. Did this all outdoors in those long under the bed type containers lol long and shallow. It all came off. Was a nice Sour D, but once jarred, well for one I did not Want to even try it lol I have bad allergies, but I could smell the peroxide in it. I tossed it and I Really do not recommend that, have no idea if you can actually get rid of all spores, and if you don''t, what that might do to the lungs. But that is just me and I look at health on a lot of this above all else. I toss all PM, knock on wood, only had it once, anything that even remotely looks like it on clones, goes to the garbage. I almost tossed a water spotted clone I freak about PM so badly lol

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It's humbling, isn't it, this lack of healthy solutions?  Since one of my main goals was to wind up with some seeds to continue propagating and selecting the Lebanese (after starting with just 5), I think my strategy is going to be:

1: chop and toss the bits of bud with visible bud rot

2: move the affected plant into a small tent indoors with better temp/humidity control

3: wait and keep my fingers crossed!

Even if the plant is a bust as smoke, if I wind up with a dozen seeds (hopefully many more), I can do another run in a more controlled environment.  I've had a fan running in the greenhouse ever since I spotted the first signs last week, so hopefully that will also help with prevention on the remaining other plants. 

Apparently the active ingredient in Defguard is "Bacillus amyloliquefaciens strain D747... a bacterium that is found globally in most terrestrial environments, "which has "produced no adverse effects (disease or toxicity) when it was administered orally to rats and it is not known to produce metabolites of toxicological concern," at least according to the Canadian government.  There's much I don't know (including whether it will actually be effective as a fungicide), but it doesn't sound inherently more dangerous than foliar spraying with compost tea?

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Looks like it is for veggie crops, I can't find any hazard warnings that are alarming. Called Double Nickle 55 in the states.

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Aha!  Thank you for cracking this case for me!  Funny, I hadn't come across that brand name before... I guess Defguard is just General Hydroponics' brand name for the stuff?  The internet seems to have a bit more info floating around for "Double Nickel 55" thank for "Defguard."

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Gosh darn it PM showed up in my friends outdoor today! As we speak. Told him to pull any that are close. Makes me sick to my stomach, two years in a row he got ripped, secure as secure this year, even sleeping out there, now PM. Booooooooo

So looking for him I ran across this, might be of interest to you :)

Presence of the fungi Trichoderma in a plant’s rhizosphere may play a crucial role in the prevention of powdery mildew. While there have been no studies directly related to the powdery mildew species that grow on cannabis, peer-reviewed studies of powdery mildew on other plants have shown that application of the species T. harzianum in soil resulted in a 75–90% reduction of powdery mildew infection on the leaves.[5]

Researchers speculate that the enzymes Trichoderma produces helps the plant to resistant powdery mildew, among other infections.

Trichoderma can be found in products such as Soil Blast on Amazon. However, note that over-application of Trichoderma may create problems with another beneficial fungi for plants, mycorrhizal fungi.

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Oh no!  Sorry to hear about your friend's (multiple) losses... this outdoor stuff is almost making me nostalgic for the days of battling spider mites inside.  Almost.

Never even heard of Trichoderma before!  It's mind-boggling to realize how little I understand what's going on in terms of soil life.  The more I read, though, the more it seems like our goal should be to encourage a healthy diversity with a little bit of everything, so that nothing can take over and cause us problems.  It reminds me of botulism--there were almost certainly botulism spores on the apple I ate today, but it isn't until we can with dangerously-low heat and kill off all the other microorganisms *except* botulism that it pose us a danger.  Maybe I'll toss some yogurt and sauerkraut into the soil next round to get those lactobacilli in the mix too:wOOt!

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My guy went out and helped him, took him our sprayer, the paint one lol you hook it up to an air thing, makes quick work of spraying. I hope he can save them. Stripped a lot of leaves, staked, tied them up. Next year he needs to defoliate more and stake sooner.

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Potassium bicarbonate– Similar to baking soda, this has the unique advantage of actually eliminating powdery mildew once it’s there. Potassium bicarbonate is a contact fungicide which kills the powdery mildew spores quickly. In addition, it’s approved for use in organic growing.

Potassium bicarbonate additives can help kill powdery mildew spores on contact, while also increasing the pH level on the surface of the leaves. A pH level above 8.3 on the surface of the leaves discourages fungi.

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