BT products would only help with budrot that is related to caterpillar damage and infestations.
caterpillar damage and poop introduces budrot. Bt isn’t going to help with budrot by itself.
Environmental controls are the best options. Planting varieties that are resistant is also important, especially if you have limited control on your environment and are in a humid area.
biologicals (Bacillus products, Stryptomyces products, Trichoderma products, teas, endophytes) can help colonize plants to compete with pathogens and unregulated the plant immune response
neem, horticulture oils can limit some molds
sulfur and Bordeaux mixture may limit some molds
I have trialed various allowable products for Oregon, and none really work well, unless @vernal wants to come explain systemic fungicides
Just want to clarify, when you say biologicals, including bacillus products, can help colonize plants to compete with pathogens etc, does that not include BT? Is it that other species of Bacillus (as opposed to Thuringiensis) specifically, have potential to be applied as more general fungicides?
Sounds like you’re saying they’re not very effective, which is sort of what I was expecting - it would need to be part of an integrated approach along with environmental controls, as you mentioned.
IDK much about fungicides for budrot, though I’m sure many of them would work. Not a big outdoor guy anymore, and since budrot is a late season occurrence that you often don’t even know is there until after harvest (unless it’s really bad), you’d have to spray mid-late season as a preventative…but obviously most people aren’t gonna do that lol. Plus it’s not like other fungi where it’s gonna spread to plants in veg, so…long story short…IDK.
Has anyone mentioned the pre flower calyxes? They ripen way before flowering finishes and should be removed from Indica dominant plants in a humid environment. These calyxes have been the source of mold on many occasions for me in the past, and I now make it common practice to remove these calyxes before they get buried by the flowers, and I smoke them to determine how good the plant is going to be. It’s a win-win
If the product has living bacteria in it, then sure. It may provide some niche competition and induced immune response in the plant. But Bacillus thuringiensis isn’t known to be specifically antagonistic to Botrytis (that doesn’t mean it isn’t or some isolates of it aren’t) Some Bt products only contain the toxin and the bacteria have been killed.
@vernal I am sure something like systemic myclobutanil would knock it out completely.
I’ve used it as an IPM and for remediation over the last couple of seasons. Third season using their program which includes a couple of their other products.
I think it works. At least, it seems that I have encountered less problems with powdery mildew and I haven’t had any botrytis issues during this time.
But, their products likely works best as a preventative. I feel that using their products at elevated concentrations (2x) to remediate an issue causes to much stress … when I’ve tried.
I’ve trialed Regalia outside and it made no difference.
This was supposed to be published on the Phylos blog… before their shit went sideways. It will probably posted on my own companies new blog eventually (Blog - Mycophyte Solutions LLC), but here is the rough draft I have been sitting on in the meantime (it needs touched up, for starters more species than just B. cinerea have been confirmed on Cannabis or I have just become aware of their confirmation in the last few years.) BotrytisStudyBlogPost.docx.pdf (67.2 KB)
I don’t doubt it at all, just you’d have to spray it way too late for almost anyone to be comfortable. It’s systemic but only provides a few weeks of residual activity at most. You could treat veg for PM and get it late flower.
Here is the LST’d main branch of a Zamaldelica clone of a clone, at flower 7 weeks.
I grow this one remotely and only can feed it every two weeks or so.
Thanks to blu mats or she’d been toasted by now.
She is dripping from a 9-1 , distilled H2O to Walmart H2O2 spray as she has a sticky, heavy mass I rarely see on sativas.
I only spray this at the beginning of the daylight cycle.
Normally I only use H2O2 after I harvest and always on outdoor plants.
But the grow room is humid and cool this time of year and 13 hrs dark doesn’t help.
I’ve lost a harvested crop to botrytis before and that just plain sucks.
And I’m glad to come across this topic.
I removed some branches at 5 weeks cuz I was out and lets just say she is promising to be much more.
Very few seeds from those branches but they are ones I didn’t intentionally pollenate.
I had to kick her out cuz she got knocked up way early.
She begged to stay, claiming she was “only a little bit preggers” but I’m just mean.
I can’t exactly see what’s going on in that first picture, but I think you’re saying flowering plants can be sprayed down with H202(3%?):water in a 1:9 ratio as a preventative / treatment measure?
I’ve noticed this as well - it does seem like they’re affected by nearby rot without exception, never really gave it any thought whether that’s where the rot starts. Definitely will give it a try.
@anon4675195 thanks for posting the results of your study, very informative but also disappointing that none of the tested treatments produced results. One thing you don’t mention is the mode of application for each treatment - Rootshield and Actinovate were by drench / fertigation, Serenade, Regalia and Trilogy were foliar? Sorry for the noob questions, I’ve never applied any of these products before so maybe this should be obvious.
In searching out myclobutanil, I got some ads for Fox Farms product Bush Doctor Force of Nature Fungicide - active ingredients sodium bicarb, cottonseed, corn, and garlic oil, oleic and lauric acids…I’m assuming this product is a gimmick, but does anybody have any experience?
Yeah I am.
Some outdoor grower here washes all his harvest with food grade 3% H2O2 and normally so do I but I am at another location and only have store bought.
Since this has several more weeks to run, I sprayed her down this am with distilled water.
Next time I’m here I’ll bring the food grade.
Various trials from university test plots. First is for hemp, the remainder on other crop. Not much outside of food crop being formally studied, currently:
Lot’s of interesting information across the use of both inorganic and organic formulations used to control a variety of fungal pathogens. It is also informative as to how widely the different formulations vary across differing plant types and infections. The design of experiments in some of these studies also illustrate the inoculation techniques to help avoid bias occurring in naturally random processes.
Thanks for pointing that out. I applied all treaments as foliar sprays with a gas powered backpack sprayer.
Rootshield WS is advertised as a root drench, so technically I may have been breaking the law applying it against labeled usage… but there is no specific reason the Trichoderma species in it or that formulation can’t be applied as a foliar.
I didn’t try enzymes, have managed to use BT in flower up to week 5 but one has to be very on top of timing with the weather outside… i.e. early morning before sunrise, allowing all day wind to dry it.
I almost never sprayed at the end of the day unless it was windy & very dry.
@gramps had good things to say about Dr Zymes i think
good timing on this subject… I just landed in Hawai’i with my dog yesterday & the dry California weed I brought re-humidified
I wish I saw this thread earlier
Recently encountered this nasty problem myself
I was inspecting the buds for ripeness and saw the tell tale signs ( dark brown patch in the middle with a different looking purple ) cut off the top of the cola I wanted to cry the bud was fn huge too !
I increased the intake fan to max also placed 2 fans oh high one on the bottom facing upward one opposite side on top facing down in to the buds.
Once I cut it down wet trimmed also to examine the buds better glad I did I found 2 more monsters tops infected chop chop gone ! Now there in jars and I just hope that’s the last of it the weed is stellar
Bud rot (botrytis) is a bastard. Basically it’s mostly a factor of the bud density and it’s ability to dry out again reasonably quickly after getting wet or to get rid of the water that occurs through transpiration.
I have tried selecting for ‘resistance’ but it seems to be entirely a morphological attribute rather than a genetic trait that can be selected for… other people may have had better luck… If you consider the environment the ‘land race’ broad and narrow leaf varieties evolved, the morphology and grow/flower cycle makes sense. Indica climates are hot and dry in summer, have very short seasons and exist in arid low humidity environments… the the sun is also lower in the sky and the plants receive less intense sunlight… hence the broad leaf for greater surface area.
‘Landrace’ sativa on the other hand have evolved in environments where the difference between summer and winter might be only an hour or less in length, they have very thin leaves because the light is intense, some of them are almost like ‘autos’ in that growth to maturity is longer and flowering times are much longer… and ‘winter’ Isn’t cold… here our cold days are 18 degrees C.
What’s interesting about these sativa is that they have much more open bud structure and tend to flower at a pace so that the maximum density isn’t reached until after the wettest period… also I have seen some sativa that have adapted so that they ‘shed’ any of the flowering bracts where rot establishes… they can do this because of the open structure of the flower… Indica can’t and so any rot is trapped and then the spores propagate.
All that said; I have found the occasional strain, or rather fkd around until I came up with a strain that seems both dense and resistant to rot… there is a bit of a natural selection process here though because anything prone to bud rot is basically fkd…
Bayer have a natural bacterial treatment called “serenade op to’ for botrytis on grapes that has no withholding period… I haven’t tried it however…
Excellent post. I have used serenade on stem rot but not Bud rot. It works really well for stem rot.
Just one thing to add about the broadleaf Afghan types. The fat leaves act as an umbrella to keep the Sun from drying out the internal flowers in that dry climate. Unfortunately, that same umbrella holds moisture in, in a wet climate.
I have found that most of the bud rot I have experienced in Afghan plants over the years is sourced from one of three things…
1). Petiols( leaf stems) that are left from pruning or dead leaves. Any leaf removal should be complete and done at the beginning of lights on or in the morning outside, to give the plant time for the wound to scar over or dry out so it doesn’t leak juices all night.
2). Seeds that have completely ripened, leaving the sheath to rot.
3). Pre flowers that have not been removed. These old calyxes get buried by the rest of the bud, and are always the first ones to mold, spreading to the rest of the bud. I always remove mine now. Good way to experience some early smoke and test potency
Studying on rot prevention as I am still quite the noob. I have a few Double-Grape Auto girls about 10 days from chop. Temps have been 90+ F and 70-90% rH with afternoon thunderstorms.
Can someone please show me a pic of what you are calling “pre-flowers”, as in the ones I should be removing. Are they the 2-4 pistils that you see before they flip?
