3 min read

Identifying Bud Rot Before a Little Issue Becomes a Big Problem

ByTrichome Team

January 17, 2023

Reading Time: 3 minutes

Growing cannabis is not that difficult. Make sure there is enough water, light and nutrients in the growing medium, establish a comfortable temperature, and the cannabis plants should be happy and ready to thrive. When the cultivation becomes commercial and there are hundreds of plants across thousands of square feet all under one roof, however, things become a bit more difficult. Although the technology and techniques used in most larger grow settings sharply decrease the chances of things going wrong, there is still plenty of room for issues to arise. 

Common Cannabis Pests

In larger cultivation settings, there are several situations that can develop even with constant attention and oversight that affect the quality of the plants, and in turn, the product.

  • Aphids
    • A common cannabis pest that feeds on the juices of stems and leaves
  • Fungus Gnats
    • Insects that damage larger roots causing weak plants, slow growth and fading foliage
  • Leaf Miners
    • Pests that eat the tissue of cannabis leaves 
  • Spider Mites
    • Their sharp mouths pierce plant cells and suck out the liquid
  • Thrips
    • They thrive on chlorophyll and turn cannabis leaves brittle and dark 
  • Whiteflies
    • Pests that steal nutrients from underneath cannabis leaves

What is Bud Rot?

Bud rot is another major problem that plagues small and large grows alike. The term “bud rot” is slang for the technical name Botrytis cinerea and refers to a pathogen that affects over 200 plant species. It is a fungus that looks like a gray-black mold, thrives in high-humidity environments and spreads in spore masses via air currents, splashing water droplets and facility workers. If Botrytis cinerea has infected cannabis plants the first sign will be water-soaked spots on the leaves. The spots are normally white or off-white in color and will eventually turn a yellowish brown. Once they begin to cover the entire leaf it will wilt completely. Other symptoms that might indicate the presence of Botrytis cinerea include:

  • Visible signs of mold
  • Mushy stems with grayish coloration
  • White and fluffy fungus on the buds
  • Rotten brown buds
  • Spots on leaves
  • Abnormal leaf growth
  • Burnt and wilted leaves
  • Purplish leaf coloring

Time to Quarantine

Once the presence of Botrytis cinerea is confirmed, the entire grow must be analyzed to judge the extent of the problem. Is the mold confined to one area? Is it only in one section of the grow? The safest course of action is to pull and destroy the infected plants without composting any of the remains. And while there are some foliar sprays with beneficial microbes that might help to address the problem, the use of those sprays will not prevent the plants from failing New Jersey’s tests for total aerobic bacteria count.

Any plants that do not show signs of Botrytis cinerea—but are near the plants that do—should be tested. It might not be visible, but since there is a known infection in nearby plants, it is imperative to be sure that the infection is contained. Trichome Analytical tests for Botrytis cinerea using DNA-based analysis (through qPCR).

How to Prevent Botrytis Cinerea

The maintenance of an ideal humidity and temperature is key. Botrytis cinerea thrives in high humidity, so a level around 40% is ideal. Keep the temperature under 70 F and thoroughly and frequently examine all of the plants in the grow in order to catch the fungi early. This is especially important in outdoor environments where the humidity cannot be manipulated. It is also important to make sure that the plants have proper drainage and there is no sitting water. Even the most advanced and modern cannabis cultivation facilities can experience Botrytis cinerea so it is best to always be prepared.

Want to learn more about Bud Rot (Botrytis cinerea) or other molds and pests that can ruin a cannabis grow? Reach out to Trichome Analytical today.