BH
Tha Dank Hoarder
Botrytis aka Budrot:
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How does B. cinerea infect plants?
Though B. cinerea has long been considered a necrotroph, newer literature is beginning to show that B. cinerea might be better classified as a hemibiotroph, meaning that it begins its life as a parasite and later transitions to a necrotrophic lifestyle . In order to succeed as a necrotroph, a fungus first has to gain a foothold in the plant, and it does this by suppressing plant immune responses for a short period of time until enough fungal biomass has accumulated in the host plant to successfully switch to a necrotrophic lifestyle and kill surrounding plant cells. For Botrytis, this is not a long time, and the very first symptoms of infection by Botrytis are necrotic lesions that begin spreading, showing that the parasitic phase is quite short-lived indeed.
So how do we know that there is a parasitic phase? As described earlier, necrotrophs must kill plant cells to feed on. However, in initial infection events, Botrytis actually interferes with the plant’s programmed cell death immune function known as the hypersensitive response (HR). The hypersensitive response is a common way for plants to defend against pathogen invasion by killing cells under attack and bolstering the defenses of neighboring cells. One might think that this is beneficial to necrotrophs, but it appears that in order to initially establish itself in the host, Botrytis must suppress PCD by secreting effector proteins and small RNAs that interfere with normal plant responses [3]. Secreted small RNAs from Botrytis ‘hijack’ the RNA interference system in plants and help silence genes involved in plant immunity [4]. Another factor that challenges the notion of Botrytis as an obligate necrotroph is the fact that it can sometimes colonize plants asymptomatically, although I am not aware of this being demonstrated yet in Cannabis [5]. This raises the question of whether B. cinerea is a fairly ubiquitous endophyte that only causes serious disease when both the environment and host are conducive to disease development (there may be cases where a necrotrophic phase is not tiggered).
What is going on biochemically during plant infection?
After accumulating biomass within the host, Botrytis can switch to a necrotrophic lifecycle, and it employs a variety of pathogenicity tactics, including inducing the HR response in plant cells rather than suppressing it. For instance, it begins to produce macromolecular toxins that can induce plant cell death [6, 7]. One such metabolite, oxalic acid, may induce these responses through acidification of plant tissues, leading to production and activation of various fungal enzymes including pectinases (pectin degrading enzymes), laccases (lignin-degrading enzymes), and proteases (protein degrading enzymes) [8, 10]. Furthermore, oxalic acid can weaken cell walls by chelating calcium ions, which is necessary for forming calcium pectate in plant cell walls [10]. In a closely related necrotrophic species, Sclerotiniasclerotiorum, oxalic acid has been shown to trigger host HR response [9]. Botrytis has also been found to produce plant hormones and/or induce plant hormone changes including ethylene and abscisic acid levels, both of which have been found to make plants more susceptible to Botrytis infection [11, 12, 13, 14]. Furthermore, different effector proteins are expressed at different points of infection. BcSpl1 is one such protein that is more abundant in later infection stages and is an important virulence factor for B. cinerea, inducing cell death [15]. Another effector, BcIEB1, may help protect the fungus from a host-produced antifungal, osmotin [16]. Most putative effector genes in Botrytis are not well characterized, and some effectors may not contribute to virulence due to host plants evolving ways to recognize the effectors and trigger defense responses, such as is the case with BcNEP1 and BcNEP2 [17]."
What is the life cycle of Botrytis?
As previously mentioned, Botrytis usually functions as an asexual fungus. In the spring, fungal mycelium and sclerotia (defined later) begin to grow/germinate and makeconidiophores that produce asexual spores known as conidia. Spores are usually dispersed through wind and water. In the presence of moisture (unlike PM, Botrytis spores require free water to germinate), the conidia (asexual spores) germinate and produce structures known as appressoria to penetrate plant cuticles through immense pressure buildup. The invasive hyphae can then grow within the extracellular space of plant tissues.
As previously discussed, they initially suppress plant responses and attempt to remain undetected while accumulating biomass. After a short period of growth, the fungus switches to a necrotrophic phase and begins to kill and rot proximal cells. After this initial foothold is established, the hyphae can continue to invade the host tissues and the fungus can produce more conidiophores on the plant tissue surface. This acts a secondary inoculum source that amplifies the spread of the disease within a given season (polycylclic disease). Come winter, the fungus begins to produce structures called sclerotia that are dense survival structures composed of highly melanized mycelium. Furthermore, mycelium can survive within dead plant tissue through the winter and produce conidia the following spring. The sexual phase is rare, but occurs when the sclerotia produce a fruiting body known as an ascocarp (analagous to a mushroom) that releases sexual spores known as ascospores.
What does bud rot look like in Cannabis? How do I diagnose it?
This disease displays both symptoms (visible effects on plant tissues) as well as signs (seeing the actual fungal tissue). However, long before you see a tuft of gray mold coming out of your buds, you will notice flagging of plant colas. This means that the tops of your colas will begin to dieback, leaving brown tissue as shown below:
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You might also first notice symptoms on foliage. If your plant is not showing signs of nutrient burn or natural senescence of late flower, it can be easy to spot random leaves that have turned brown and dry, such as below:
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Everything You Need to Know About Botrytis Bud Rot in Cannabis
Bud rot is one of the most devastating things a grower can deal with. This day and age, when a positive microbial test can cause a grower to lose their crop, there is zero tolerance for fungal path…
indicainfo.com
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PLANT GENETICS
Just like with humans, genetics plays a role in overall plant health. In this case, certain strains may be more predisposed to bud rot.Let’s take a look at the two primary strain types: sativa and indica. In general, sativas adapted to the climates of warmer, more humid regions of the world. Thus, they have lighter, longer, wispier buds, which makes them more resistant to mould.
Indicas, on the other hand, developed in drier climates, so once you introduce humidity into the equation, their dense buds become much more susceptible to mould growth.
As such, the type of strain you choose to grow depends largely on the climate of your location and/or the setup of your indoor grow space.
DENSE BUDS AND FOLIAGE
Speaking of dense buds, these are the type that are most vulnerable to Botrytis attack. That’s because plants with massive colas (a bud cluster that grows tightly together) trap moisture inside.And because there isn’t any air exposure, all of that moisture builds up over time. Eventually, mould will start to develop and consume the entire plant.
If these are the type of buds you’re growing, it’ll be best to keep a watchful eye on them—especially if you’re growing outdoors where you have very little control over the surrounding environment.
HOW TO IDENTIFY BUD ROT ON CANNABIS PLANTS
View attachment 103436They say prevention is better than cure. But if bud rot attacks before your preventive measures, then you should know how to spot it before it’s too late.
WHAT DOES BUD ROT LOOK LIKE?
To spot the first signs of bud rot, you must know where to look, and what to look for. Here are the common symptoms of bud rot, which will manifest differently depending on the stage of development.Bud Symptoms
This is one of the first signs you’ll see. Apart from discolouration around your buds, you’ll also see chunks that look crumbly and dry.
Furthermore, you’ll notice a very distinct slimy texture upon touching mouldy buds. And you’ll know that a full infestation has occurred when the infected region easily breaks off.
PREVENTING BUD ROT WHILE DRYING CANNABIS
Moulds and fungi can still develop during the drying process. Here are some ways to prevent bud rot during this stage:- Check your colas for any signs of rotting and immediately discard if you see some.
- Adjust the temperature and humidity levels of your drying room accordingly.
- If you’re growing during the rainy season, try to time your harvest for when there is the least precipitation. Ideally, you’d want a dry spell of a few days
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Cannabis bud rot: How to avoid, identify, and get rid of it - CannaConnection
Cannabis bud rot is something no grower wants to contend with. But it is a situation you can definitely prevent, as you'll read in this article.
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Botrytis blight, aka bud rot or gray mold, is a fungal disease that affects over 200 plant species. In cannabis, the disease causes a soft rot that damages buds during growth and after harvest.
The agent of gray mold is the asexual fungus Botrytis cinerea. Its name roughly translates to “grape disease” in Greek. Botrytis cinerea is an airborne plant pathogen with a necrotrophic lifestyle. The ability to induce programmed cell death plays a key role in the success of the fungi.
Gray mold appears as a thick carpet of velvety spore mass. Affected plant areas gain a fuzzy web of gray/blue mycelium, visible to the human eye.
As bud rot progresses, the damaged, water-soaked plant material collapses into black mush.
The earliest symptoms of gray mold on cannabis typically appear as small bruises or discoloring of the bud. The bruises collapse into rot, followed by the formation of the mycelium, gray mold.
Other symptoms include yellowing and damping-off of leaves close to the infection. Regular inspection for gray mold can be done by carefully opening buds and checking inside, where gray mold tends to hide."
How to Stop Botrytis on Cannabis (Bud Rot, Gray Mold) - Mold Resistant Strains
Get rid of Botrytis (bud rot, gray mold) on marijuana. The best ways to stop gray mold fast and prevent it from spreading.
moldresistantstrains.com
How to Avoid Bud Rot on Cannabis
While treatments exist that can smother or kill the fungus, applying chemicals to your plants can be risky.For instance, there have been cannabis recalls due to one particular fungicide treatment that, when burned, turns into what Jones described as a “hydrogen cyanide type gas.” Chemical use also can be an issue if you grow organic or medical-grade cannabis.
For those reasons, and for cost and efficiency’s sake, most large-scale growers will simply destroy plants affected by bud rot.
That’s why most experts recommend focusing on bud rot prevention. To that end, four factors affect your susceptibility to bud rot.
- Temperature. The ideal temperature recommended for your grow varies depending on several factors, but keep in mind that bud rot prefers cooler temperatures. Most experts recommend temperatures above 68°F to keep bud rot at bay. In a greenhouse, try to avoid cold nights by using a heater.
- Presence of Spores. If you grow indoors, it’s much easier to avoid Botrytis cinerea spores, but you still should be careful about what you let come indoors. Change clothes before you enter your growroom, and never let pets inside.
- Food Source. Remember that bud rot likes the parts of your plants that have the most moisture, so you’ll need to keep an eye on your denser colas. Of course, if you see infection remove it immediately and don’t let the infected parts of your plants touch those that haven’t been affected.
- Humidity. For indoor growers, limiting humidity is one of the easiest ways to avoid problems with bud rot. (More on this critical topic below.)
Don’t Forget Strain Selection
Of course, if problems like bud rot keep cropping up, Jones suggested it may simply be that you’re growing the wrong strain for your conditions.“When in doubt, pick a different plant,” Jones said. “If it happens too much, the density of the flower may be the problem, and selecting a different strain may do more than anything you can do with treatment and prevention.”
The How and Why of Humidity Control
There are a number of ways to think about humidity control relative to crop problems such as bud rot. For outdoor growers, simple tips include avoiding planting in the shade or too close to walls, which can restrict ventilation.Indoor grows require a bit more environmental care, especially once the operation goes beyond a few plants for personal use.
“If you’re growing indoors, you might not have problems when you first start out in your home, because the home environment is already controlled, said Clif Tomasini, business director at Quest Dehumidifiers. “Your house already has a cooling system, a ventilation system. But you can get to a tipping point where you exceed the capabilities of your home—your home wasn’t designed for all those plants.”
The challenge often comes from growers who go from hobbyist to commercial grower who don’t understand the science of climate control.
“They don’t know why they’re having problems like bud rot,” Tomasini said.
What Is the Ideal Humidity Level?
The ideal humidity level for growing depends on a number of factors—including who you ask.“If you ask the environment guys, we’re going to tell you any time you’re below 50 percent relative humidity and you have good air circulation, you’re safe,” Tomasini said. “But someone who is really focused on optimal plant growth may recommend something higher, because some plants reach their full potential under different conditions.”
“On the hobby side of things, the two easiest, most affordable things are to make sure you have good ventilation and good air circulation,” Tomasini added, as stagnant air can trap humidity, especially around densely-leafed areas.
Encouraging ventilation can be as simple as having a good fan in your grow room.
Of course, whether you need dehumidification depends on where you live, the time of year and grow technique. In more humid climates, such as the Pacific Northwest or New England, dehumidification is critical. However, if you live somewhere like Arizona, your need for dehumidification is very different, Tomasini said."
Nipping Bud Rot in the Bud: Stop Crop Loss Before it Starts
As your grows get bigger and yield more cannabis, the last thing you need is for crop loss to strike. That’s why you have to educate yourself about bud rot. “It’s very common, especially outdoors,” said Dan Kibbin, a Maine-based cannabis grower with 25 years of experience. “But I’ve experienced...
hightimes.com
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Other good information ( more coming sooon)
8 Core Components of a Cannabis IPM Program — Elevated Botanist
Like other high-density crops, cannabis is susceptible to pestilence and disease, particularly during the late flowering stage. Fortunately, it is possible to manage pest pressures, and produce clean compliant cannabis without the use of systemic pesticides. To achieve this goal, growers need to
www.elevatedbotanist.com
Videos focused on Cannabis Bud rot information and prevention/Control:
BuildASoil 10x10: HOW TO PREVENT BUD ROT: Season 2, Episode 18
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BUDROT IPM guide and product suggestions coming soon !
