Jump to content
Summer giveaway, Set of 4 Medical Cannabis Coasters Read more... ×
  • Recently Browsing   0 members

    No registered users viewing this page.

Purple Power

Pest: Bud Rot

Recommended Posts

Pest: Bud Rot




(Botrytis Cinerea)





Infected buds, leaves, stem, or root with Botrytis Cinerea should never be consumed since they can easily cause a lung infection known as“winegrower’s lung”, which is a rare form of hypersensitivity pneumonitis. It's an allergic reaction in the lung and airways that affects some who are predisposed. We can’t avoid mold spores, they are literally everywhere, and we smoke some in every joint without concern. Some medical marijuana patients however have compromised immune systems or respiratory problems and can become quite sick from smoking cannabis with high spore content. If your garden has had a severe outbreak of botrytis or any other fungus, it is imperative that you remove all infected bud and have your cannabis lab tested before offering it to patients.


Symptoms vary from mild to severe. Acute symptoms may last up to three weeks, and symptoms often include shortness of breath, cough, burning sensation in the chest, malaise, chills and fever. The symptoms may persist for as little as 12 hours or as long as 10 days. Between attacks, the person may experience no symptoms.


Chronic hypersensitivity pneumonitis lasts longer than three weeks. After repeated exposure to an allergen, a chronic cough may develop with excessive sputum, which often contains pus. The patient may also develop a chronic shortness of breath, decreased appetite and weight loss. Clubbing (enlarged fingers and toes) is seen in about 50% of patients with chronic hypersensitivity pneumonitis. Tachypnea (rapid breathing), respiratory distress and rales (crackling sound in the chest, as a result from fluid in the alveoli) may occur.


Chronic hypersensitivity pneumonitis may lead to pulmonary fibrosis (scarring of the lung tissue), which is usually irreversible.


A blood test can help detect allergies. A high-resolution CT-scan of the lungs may be performed to confirm a diagnosis.



Would you eat this strawberry? 220px-Aardbei_Lambada_vruchtrot_Botrytis


If you wouldn't,  then why would you smoke this?   Angel-2-moisi1-300x225-300x225.jpg



Special Species Notes:


"Botrytis" from Ancient Greek botrys (βότρυς) meaning "grapes".  It's a necrotrophic fungus that affects many plant species. It's from the Order: Helotiales, family: Sclerotiniaceae; Genus: Botrytis


The fungus is usually referred to by its anamorph (asexual form) name, because the sexual phase is rarely observed. The teleomorph (sexual form) is an ascomycete, Botryotinia fuckeliana, also known as Botryotinia cinerea. is a type of fungus or fungal disease. It's also known as bud/gray mold, Botrytis, botrytis bunch rot.


Actually, it is probably the most common fungus in cannabis crops, indoors, outdoors or in greenhouses, and it usually affects plants during their latest stage of flowering, and the drying process. It should be noted that even dried and stored cannabis are not safe from botrytis and should be inspected regularly.


If an outbreak is left unchecked, botrytis can spread to all of your plants and entirely destroy your garden in as little as a week. Like all fungi, it thrives in climates that are humid and cool. Gliocladium roseum is a fungal parasite of Botrytis cinerea ,which are toxic to organisms including other fungi, bacteria, nematodes, insects, and is of interest as a biological pest control agent. Clonostachys rosea protects plants against Botrytis cinerea by suppressing spore  production. Its hyphar have been found to coil around, penetrate, and grow inside the hyphae and conidia of Botrytis cinerea. Botrytis cinerea not only infects plants, it also hosts several mycoviruses itself. mycoviruses are able to infect other healthy fungi. A range of phenotypic alterations due to the mycoviral infection have been observed from symptomless to mild impact, or more severe phenotypic changes including reduction in growth/suppression of mycelia, sporulation and sclerotia production, formation of abnormal colony sectors and virulence.More on this below.


In dealing with Botrytis, nothing could be truer than “an ounce of prevention is worth a pound of medicine”.





Common Species:


There are many genetic varieties of Botrytis cinerea, but all persist through the winter months in the form of sclerotia or mycelia.  In the spring, both the sclerotia and the myscelia produce conidiophores which grow millions of asexual spores (conidia) that are then spread by wind and rain.









Change in the colors and texture of the plant. Leaves develop necrosis and dry out very fast. Stems become fragile, brown and ulcerated.


Bud rot can occur anywhere and anytime, even when your cannabis plants do not yet have buds. The temperature and humidity level are the most important determining factors in how at risk your cannabis plants are for getting bud rot.



How it spreads:


Your cannabis plants won’t get bud rot unless they are physically exposed to gray mold because it spreads from place to place through its dusty spores that either travel through water or dispersed by the wind.  Botrytis spores can remain latent for years in the environment until climate conditions are favorable for their growth.


First signs:





Any part of the plant can be attacked by Botrytis: buds, stems, leaves, etc. Botrytis commonly infects tissue through injuries and forms gray, velvety mats of sporulating tissues. The first visible symptom is a change in the colors and texture of the plant. Leaves develop  necrosis and dry out very fast. Stems become fragile, brown and ulcerated. The most common place to find this fungus is in the buds. They become pale-gray, dry out and develop a cotton-like substance in the interior part.






Life cycle:


Temperature:  The ideal temperature for botrytis growth is between 62-77F (17ºC-25ºC), though it can grow with higher temperatures. A great difference between day and night temperatures can also stimulate the appearance of Gray Mold.


Humidity: humidity levels raise when temperatures drastically drop at the end of the day.

It grows better with high humidity levels, so keeping the humidity below 50% during the whole flowering period. This highly reduces the chances for our plants of being attacked by botrytis.


Botrytis cinerea is characterized by abundant hyaline conida (asexual spores) borne on grey, branching tree-like conidiophores.. The fungus also produces highly resistant sclerotia as survival structures in older cultures. It overwinters as sclerotia or intact mycelia,  both of which germinate in spring to produce conidiophores. The conidia, dispersed by wind and by rain/water, cause new infections.






Host plants:


Botrytis affects more than 220 plant species. Some examples are strawberries, grapes (especially wine grapes), tomatoes, peonies,  bulb crops, rhubarb, snowdrops, white meadowfoam, western hemlock , Douglas-fir and cannabis.


What To Do: Prevention


Although bud rot can be absolutely devastating, there is some good news, there are specific things you can do to prevent it from ever taking hold on your precious cannabis plants to begin with. This means not only keeping the environment a toasty warm, dry place with good ventilation, but also taking other types of precautions to prevent any unnecessary risk of gray mold exposure.


Preventative measures that should be taken include changing your clothes before going into the grow room, as clothes can easily serve as transport for bud rot spores. This has  the added benefit of being preventative for a number of other pests being exposed to your plants. If you were working in your vegetable garden or doing the yard work, take a shower too. If you happen to have a cat or dog, be sure they always stays away from your grow room especially if they are allowed to go outdoors. Although, I know this can be hard or impossible at times when they are determined to get some leaf or sun bath under the light,.... least my cats are. One of my cats prefers a grow light over the sun. My cats are indoor only to reduce that chance of them carrying something in.


Excess nitrogen at the end of the flowering period can also increase the appearance of Botrytis. Although this is a rare because we usually don’t give nitrogen to our plants at this stage. Especially, just before harvest cause we have been flushing our plants with straight water for weeks which is good for the plant's health and gives us tasty medicine/buds.


CO2 generators produce more than just CO2, they also produce heat and water vapor. The heat will help keep the room above 70 degrees, but the water vapor increases humidity that must be dealt with. Make sure you are only running your CO2 generator during the daylight hours since this is the only time the plants benefit from CO2 anyway.


Keeping the space clean is very important to prevent any kind of pest or disease. You should clean it often and remove any decaying plant debris (I do daily as I leave). Any types of tools that you use on your cannabis plants should be sanitized before and after use. The same applies to outdoor grow setups as much as possible.


As a general rule of thumb, the temperature of your grow room should always stay above 70F (21C). This said there should also be enough humidity for your plants to stay healthy, it should remain below 50%. This is crucial when trying to avoid the development of bud rot. In addition to keeping the grow room or garden as free of spores as possible, you must also maintain an environment healthy for cannabis plants, but inhospitable to botrytis. Fungi that affect cannabis plants thrive in conditions with overly wet, soggy soil, humid air, and poor air circulation. These problems can generally all be fixed through adjusting your watering schedule and proper ventilation.


A way of preventing the development of bud rot is not to let your plants get too bushy and dense in terms of leaf growth. You can train or prune your plants to maintain the proper shape without too high of a density, thus allowing plenty of ventilation (air) to penetrate the foliage of your plants. Plants with densely growing leaves are more likely to develop bud rot because there is a greater opportunity for moisture to get trapped.


The best way to remove any leaves is to take away the ones that are already receiving little or no direct sunlight, or ones that are blocking numerous other leaves from getting lots of direct sunlight. Before I remove the leaf, I move it out of the way to see how the light penetrates the plant and how many shaded leaves get light. If I like what I see, I remove it. Using selective pruning to remove any unnecessary foliage or stems from the lower parts of the plant.. This will be the most efficient way to lower the density of your cannabis plant's leaves. Pruning your cannabis plants should be done carefully. Make sure you don’t remove a high number of leaves all at once, as this will not only shock the plant, but will also cause your plant to lose many valuable sources of energy. I prune my plants daily, taking a little here, and little there.


We should also leave enough space between plants to promote better air circulation, so that humidity doesn’t remain inside our growing space, avoid over crowding them (too close together). This is something you need to consider when transplanting and placing the pot/container. It doesn't matter if they are outdoors, indoors, in small to large pots, or in the ground. You must maintain airflow through the plants themselves and around them. They will grow and may encroach upon each other if placed too close. Keeping air moving across your plants does wonders for keeping them dry and healthy. The key is to make sure the air is touching all parts of the plant, not just the tops.


Improving ventilation isn't just limited to pruning the plant, but also making sure the ventilation system (air extractor, interior fans, etc.) and/or use a dehumidifier is doing there job in the room. If your grow room uses ventilation to keep it cool, make sure your fan is strong enough to quickly remove moist air sufficiently. Oscillating circulation fans will prevent pockets of moisture and help move air through the plants foliage and across the surface of the growing medium. An added benefit of circulation fans is that this airflow will also strengthen the plants stems, so you won’t require as much staking towards harvest.


It is very important to maintain a humidity level in your grow room under 50% and a temperature that is above 70 degrees F. Warm air holds more water than cool air. So make sure you are not over watering your plants.  The extra water in the room or pooling water in your garden will evaporate causing the humidity to increase. So don't forget to dump out those saucers before you leave.


If you are running a sealed grow room or the air outside is above 50% humidity, you may need to stop drawing in outside air and use sealed light hoods and a small air conditioning unit to keep the rooms humidity low and the air within the correct temperature range. Make sure any outside air that is drawn into the room is filtered to remove as many outside contaminants as possible. A dehumidifier can quickly and inexpensively remove extra moisture from the air while helping to heat the room. Dehumidifiers are easy to use but must be emptied daily, they create some heat and generally draw between 400 and 700 watts.


From a general point of view, mostly Indica strains develop harder and more compact buds, this makes them more sensitive to fungal attacks than Sativa flowers, which develop less compact and dense, allowing better air circulation and retaining less moisture. However, there are a few exceptions among Indica plants, like the White Domina, Green poison, High Level or Philo Skunk, Gokunk, or Pakistan Chitral Kush. You may also consider hybrid crosses too.


Since botrytis usually attacks the biggest and dense buds, pruning the tops of the plants can help. A plant with multiple tops usually develops slightly smaller buds where Botrytis doesn’t g row so easily. The biggest and dense buds might be pretty on the outside, but they are basically sponges with no airflow and full of moisture, the perfect environment for botrytis. To open up a bud like that is sickening when you see botrytis and have to throw it away.






Watering is also an important thing to think about. Pay careful attention to your watering schedule, rather the timing of your watering schedule. The best time to water cannabis plants which may be at any risk for developing botrytis is after the sun is up, during the heat of the day, (late morning to middle of the day) or lights have come on and your room has reached its normal daytime temperature allows them to properly dry out.  This way the majority of the water evaporation takes place during the warm period which will not increase the humidity of the grow room nearly as much before the cooler, dark night cycle takes place, which is when bud rot has the best conditions to start developing. Even indoor marijuana setups can follow this. Whatever type of setup you have, make sure your plants have an adequate amount of time to dry out afterward before nighttime or the lights are turned off.


At the end of the flowering phase, reduce the amount of water in each watering, since too much water can affect the flowers (which could rot). During this stage, wait until the pot has completely dried before watering again. If outdoors and in the ground or very large pot, use a stick of bamboo and put it in the ground (I use several around the plant), and use it like a dipstick. To check the water/moisture in the ground pull them out and look, there will be a change of color where it is dry vs. moisture in the soil. I also do this while watering to check the depth of water. Then put them back in the soil. I usually put it in a different, but close spot. Be careful if the stick is close to the plant, you don't want to damage the roots.  In addition to over watering, another common mistake for indoor gardens and greenhouses is using larger containers and more growing medium then necessary. While you certainly don’t want your plants to be root-bound, too much soil means extra expense on nutrients, extra water and extra humidity from evaporation. Before my plants went in to the ground, a 45 gal smart pot was perfect.


For outdoor plants, we are at the mercy of the weather. Outdoors plants are at the greatest risk for developing bud rot after rain. If there is rain in the forecast and you know well enough in advance (I highly recommend checking the weather often from several places), try putting a tarp over the plants to prevent most of the water from getting on them. Be sure that there are no spots for water to pool on the tarp. If rain starts and the plants aren't very wet yet, shake them and use a large garbage bags, cover your plants. Just make sure you take them off as soon as possible and shake the plant.  If the rain happened before you could do anything, get back to your plants as soon as possible and physically shake each one of them, and be prepared to get soaked in cold rainwater when shaking them. Check your plants at least twice a day. I usually check more often as they get closer to harvest and weather (rain, high humidity, etc.).


If you do discover bud rot on any of your plants, remove the entire plant right away. Losing one plant to protect the others is well worth it. Whatever you do, don’t add this plant to a compost pile, as that will spread the mold far and wide. Seal it into a plastic bag and then discard it. Some people manage to prune the affected parts of the plants successfully, and the rest of the plant continues living. This is by no means a surefire way of saving the plant, however, it is very time consuming. I can easily spend hours inspecting plants and removing gray mold infected parts from a plant.


Once an outbreak of Botrytis is discovered it is imperative that you take action immediately. If the conditions are right, an outbreak can spread and wipe out an entire garden of buds in a matter of days. Sterilize your pruning shears in alcohol and cut the bud at least one inch below the affected area. Cut the stem (just removed) length wise to make sure, if you see unhealthy steam (less then an inch) cut more off, and wipe/clean your scissors after every cut you make.


You must be very gentle while removing the bud to prevent spreading the spores. The infected parts fall apart easily. Make sure not to let the bud, your hands or the scissors/shears touch any other buds, stem, or leaf until they have been sterilized.


If you're are indoors, once every bud has been inspected, and the damaged areas are removed, drop the humidity in the room as low as possible and make sure the temperature does not fall below 70 degrees. If the humidity can be maintained below 50%, continue to treat with biological foliar sprays all the way until harvest.


Keep in mind, you may need to harvest your plants early if you start seeing widespread signs of bud rot. If I see it bad in one plant (more then 2 buds), or see it light in 2 or more plants, I harvest early.  Harvesting early does come with a greater risk of mold developing during the drying process, so remember that the risk does not go away once you’ve harvested. When drying the buds, they should be in a single layer and spaced out with air flow (fan). I take as much timber out as possible when trimming.






As a preventative measure plants can be treated with foliar sprays. These can be either a non organic chemical based fungicide, an organic fungicide containing copper or sulfur, or they can be inoculated with foliar sprays containing beneficial fungi. Wear the appropriate personal protective equipment (PPE), carefully read ALL lables. Whatever you do, don’t use fungicides when your plants are in their flowering phase. This could have a detrimental effect on the taste and smell of your buds. If you do discover gray mold in your indoor grow setup, there is probably something about the environment that you can change to make it less hospitable to this pest.


Using biofungicides. This is Biological Warfare at its Finest.  They are formulations of living organisms that are used to control the activity of plant pathogenic fungi and bacteria. The concept of biofungicides is based upon observations of natural processes where beneficial microorganisms, usually isolated from soil, hinder the activity of plant pathogens. Biocontrol microorganisms are free-living fungi, bacteria, or actinomycetes that are active in root, soil, and foliar environments.  These microorganisms produce a wide range of antibiotic substances, parasitize other fungi, compete with other fungi, and induce localized or systemic resistance to a variety of plant pathogens. The use of composts and suppressive growing medium, which both contain living microorganisms, to ameliorate disease is another example of this disease management option.


Gliocladium is a species of parasitic fungus living in the soil. It produces volatile organic compounds which are toxic to other fungi and bacteria. Gliocladium protects cannabis from gray mold by suppressing spore production. It is best applied as a soil drench and is available under several brand names.


Plant Shield, Root Shield, PreStop, SoilGard, and T-22 PlanterBox are commercial formulations of Trichoderma species and the closely related Gliocladium species. Species of Trichoderma are the best studied of all biocontrol organisms. These species are also abundant in many types of compost and are the most frequently isolated soil fungi from all temperate and tropical soils. The production of antibiotics by these species is well documented.  In fact, Trichoderma species have been found to be highly resistant to a variety of toxins and antibiotics produced by soil microorganisms, antimicrobial compounds produced by plants, and even chemical fungicides. This makes these fungi active colonizers of toxic environments and a strong competitor. Trichoderma (beneficial fungi)- attacks fungal pathogens. brands include shield, root shield, trichodex, biotrek.


Pseudominas (beneficial fungi)


Companion and Cease are bacteria in the species Bacillus. Many biofungicides that consist of bacteria are labeled mainly for soilborne diseases, though there are some that are also labeled for foliar diseases like leaf spots, powdery mildew, botryitis,  and downy mildew.


Bacillus Subtilis is a naturally occurring anti-fungal bacterium found in soils. bacillus subtilis spray Biological based foliar sprays containing Gliocladium and Trichoderma species. It has proven to fight blight, gray mold and several strains of mildew, yet has no adverse affects on the environment or humans. For this reason, it has been approved as a fungicide and bactericide for use in organic farming. Bacillus Subtilis compounds prevents pathogens from colonizing crops. This biological fungicide can be procured online under several brand names. Two strains are available; one for foliage applications (QST 713) and one to be used as a soil amendment at the time of planting (GB03 or MBI600). Trade name Cease, bacillus subtilis QST 713, Compaion liquid bacillus subtilis GB03or products like Serenade that contain Bacillus subtilis can be used to both prevent and treat outbreaks of botrytis all the way up until harvest. These species are also fungi’s but colonize plants in a symbiotic relationship protecting them against fugal attacks. The bacillus subtilis is more effective than the pathogen at gathering critical nutrients or space and, therefore, must be in place before disease onset. Antibiosis: The bacillus subtilis produces a chemical compound of some type (antibiotic or toxin) that acts against the pathogen. Iredation or parasitism: bacillus subtilis directly attacks the pathogen. Induction of host plant resistance: bacillus subtilis triggers a defensive response in the host plant that limits the ability of the pathogen to invade the plant.


Regalia Reynoutria sachalinensis Botrytis, Leaf Spots, Powdery Mildew, bacterial diseases,  Rhizoctonia, Pythium, Phytophthora, Fusarium, Verticillium for Herbs and spices. Soil treatment. Plant health promoter


Bacillus Pumilus is a spore-bearing bacterium found in soil. It is resistant to environmental stresses, include UV light. The growth of Bacillus Pumilus on plant roots prevents Fusarium spores from germinating. A commercial product is available by the name of Sonata. Application boosts the cannabis plants’ immune system, inhibiting fungal germination and growth.


Streptomyces lydicus  WYEC 108 broad spectrum antifungal biocontrol agent. The optimal temperature and substrate concentration for maximal chitinase production were 77-86F (25–30°C) . When applied to soil mixes or turf grass, the bacterium protects the plant against a range of root decay fungi. Streptomyces lydicus strain WYEC 108 can also be applied to plant foliage in greenhouses to control powdery mildew. It is approved on vegetable commercial agriculture as a soil drench or foliar treatment in CA. for powdery mildew, Downy mildew, Botrytis. trade name Actinovate. S. lydicus colonizes  growing root tips of plants and acts as a mycoparasite of fungal root pathogens which helps protect the plants. Other possible mechanisms include the production and excretion of antifungal metabolites (e.g., antibiotics and/or low molecular weight antifungal compounds or lytic enzymes like chitinase) after colonization. To learn more about Streptomyces lydicus WYEC 108  click links https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/decision_PC-006327_15-Feb-05.pdf




So far for products I've found Actinovate SP Bio-Fungicide 100% Soluble Powder Streptomyces lydicus WYEC 108: https://www.organicapproach.com/p-3518-actinovate-sp-bio-fungicide100-soluble-powder-streptomyces-lydicus-wyec-108.aspx?CatID=100


Eagle 20EW. This product is effective and, therefore, popular with many gardeners. The active ingredient is Myclobutanil. Eagle 20EW acts as a systemic with a residual presence in the plant. For this reason, treating a plant once or twice in its vegetative stage is often sufficient enough to successfully suppress powdery mildew. This is also the reason to avoid treating plants with it during the latter stages of growth. Eagle 20EW can be used as a preventative treatment when introducing new plants to your garden from outside gardens. It can also be an effective knockdown treatment when other options have failed to break the pathogenic cycle. That being said, it should not be overused. Science has proved that overuse of fungicides, like Eagle 20EW, can result in some fungi becoming resistant to them. For this reason, the product label recommends alternating it with other products after two consecutive uses. Use personal protective equipment and carefully read the labels before mixing and using.


using a spray such as bacillus an oil-based spray, like neem oil, coriander oil, fish oil ,or sesame oil. They form a sort of shield against the development of mold. Potassium Bicarbonate will do the same thing. Sesame oil spray destroys molds and spores.


Neem oil – This is a readily available organic option to disease and pest control. Neem oil is extracted from the neem tree, native to India. This is an effective disease control and a broad spectrum, natural insecticide that is kinder to beneficial insects and mammals. As for controlling powdery mildew, results vary but it is not the best option. Results are usually moderate at best. Neem oil is a rather weak fungicide. Spray onto your plants so that there is another barrier preventing the gray mold from getting started growing


Potassium bicarbonate-based fungicide has been proven to cure and prevent powdery mildew, blackspot, downy mildew, blights, molds and other plant diseases, such as Botrytis cinerea. It is a fertilizer and a fungicide, use 1%.


Sulfur, copper, and Lime/Sulfur – Direct contact by sulfur prevents disease spores from developing. When mixed with hydrated lime, the solution will penetrate leaves for even greater effectiveness. A widely available version of this combination includes. it can be in the form of a spray, vaporizer, or burner.  Copper has been as a fungicide for more than 100 years. Copper sulphate and hydrated lime, known as Bordeaux mix. However, all of these solutions can burn plant tissue and is damaging to microorganisms in the soil and harmful to beneficial insects. It is also considered moderately toxic to mammals and humans. Copper sulfate mixed with slaked line, used commonly by vineyard workers to prevent bud rot. Copper soap and copper spray are also available for use throughout your plants’ lives. spray your plants with sulfur, so the treatment takes to the air and spreads. Chemical and copper or sulfur based fungicides can’t be used along with biological sprays because they kill fungi indiscriminately and will effectively wipe out your beneficial fungi along with the harmful parasite.  Do not apply in temperatures above 90F and less than 50 percent humidity. It stays on foliage until washed off. Use sparingly and with caution if at all: Wear a mask, gloves, and safety goggles; cover exposed skin and hair. Avoid skin, eye, ear, and nose contact. Irritates eyes, lungs, and skin. While often effective, the drawback is that chemical or copper and sulfur bases sprays is they can only be used during a vegetative period. These organic and non-organic chemical sprays can be extremely harmful if smoked, especially for medical marijuana patients, and should never be used after your plants begin to flower.














The link below will take you to "An Intro to beneficial bugs and beneficial insect food" it has a list (been worked on) to pests and beneficial insects




Classy, sassy, and a bit of a smart assy

Share this post

Link to post
Share on other sites

IME botrytis can also be treated with H2O2 sprayed on, greencure or other method of changing the ph beyond the spores ability to survive.

Even UV-c can help kill botrytis.


IT WONT, however, remove the dead spores! Spores, even dead ones CAN effect some to many people! Smoking spore-free bud is the IDEAL situation.



Edited by IammuA

Share this post

Link to post
Share on other sites