With increases in marijuana production, a particular problem has begun to emerge: mold. Cannabis is actually very susceptible to mold, and if not stored properly, it can ruin your entire stash. Moldy bud is (generally) easy to spot. It typically looks like wispy white fuzz, in essence, it looks like mold. If you think moldy weed may not be as dangerous as, say, moldy bread, well that is most definitely not the case. Have you ever had to move out of an apartment or house because of mold? That is because inhalation of mold is extremely hazardous to your health. So is smoking moldy marijuana just as dangerous?
Photo source: Herb
The most typical types of mold that could grow on cannabis (the flower or the leaves) are Botrytis (aka "bud rot"), Cladosporium, Mucor, Penicillium (yes, where penicillin comes from), and Rhizopus. The common causes of mold are similar to most plant material: for example, wet conditions, humidity, lack of ventilation, improper storage, moisture, etc.
If one does decide to smoke moldy weed, possible acute reactions can range from allergic reactions to poisoning by toxins produced by molds. A smell of mildew can indicate mold, and even smelling the bud can cause coughing or sneezing. More chronic conditions from smoking moldy weed can be more severe. Chronic exposure to mold, of any kind, can lead to sensitization to other microorganisms, infection, and immunologic lung disorders. Marijuana smokers can increase their chances of developing these conditions due to microorganisms present on pot.
In fact, in a case study report published in 2011, researchers documented the cases of two patients with chronic pulmonary aspergillosis. Although relatively rare, cases due to marijuana have been previously reported. It is important to note that, in immunocompromised patients and those suffering from cancer, these mold-bourne illnesses can be deadly. This may give some pause before using marijuana to treat certain conditions, including cancer.
Photo source: NCSM
Are there ways to "clean" marijuana from mold? For instance, will the mold burn off during combustion or vaporization? According to one website, baking 300°F degrees for 15 minutes in an oven should remove most forms of mold. Marijuana combusts around 329–374°F and starts to vaporize at about 300°F (however, most vaporizers on the market today range from 330 - 375°F). Unfortunately, heat can deactivate mold but does not kill it. According to the Image Permanence Institute (devoted to sustainable practices to maintain art including mold prevention), "[I]t is not feasible to control mold growth by controlling temperature alone". So, it would appear that the best way to deal with mold on marijuana is the same way to deal with mold on food: throw it out.
Here's a video which describes more about mold on marijuana.
Video source: YouTube.com
Sources: leafly.com, www.ncsm.nl, Mold and Bacteria Consulting Laboratories, Journal of Allergy and Clinical Immunology, Mediterranean Journal of Hematology and Infectious Diseases, Wikipedia - Chronic pulmonary aspergillosis, sparkreport.net, Ask Ed: Marijuana Gold: Trash to Stash, Image Permanence Institute