Teaching Healthy Cultivation · Pest & Disease Library
Identify the organism or disorder before choosing a response.
These profiles are evidence-first references. A symptom photo can suggest possibilities, but confirmation may require magnification, repeated scouting, microscopy, molecular testing, or a diagnostic laboratory.
Spider Mites
Spider mites are tiny arachnids that feed on plant cells. Early infestations can be easy to miss because damage may appear before obvious webbing.
Thrips
Thrips are slender insects whose feeding can create silvery scars, distorted young growth, and dark fecal specks. Several life stages may occur in different parts of the crop environment.
Fungus Gnats
Adult fungus gnats are small flies often associated with moist organic substrates. Larvae develop in the root zone and can feed on organic matter, fungi, and tender roots.
Aphids
Aphids are soft-bodied sap-feeding insects that may cluster on growing tips, stems, or leaf undersides. Honeydew and cast skins can be important clues.
Whiteflies
Whiteflies are small sap-feeding insects. Adults may fly when leaves are disturbed, while immature stages remain attached to leaf undersides.
Broad & Russet Mite Suspicion
Broad and russet mites are extremely small and may cause distorted new growth, bronzing, reduced vigor, or flower damage. Visual symptoms alone are not sufficient for confirmation.
Caterpillars & Chewing Larvae
Caterpillars and other chewing larvae remove tissue directly and can hide inside dense foliage or flowers. Frass is often an important clue.
Powdery Mildew
Powdery mildew presents as superficial white fungal growth on susceptible tissue. Similar-looking residues make confirmation important before management decisions are made.
Botrytis / Gray Mold Suspicion
Botrytis can infect damaged or senescing tissues and is especially concerning in dense flowering material. Internal decay may be present before the exterior looks severe.
Root-Zone Disease Complex
Brown roots, weak growth, wilt, or root loss can result from low oxygen, temperature, salinity, physical injury, pathogens, or combinations of these factors. Root appearance alone rarely identifies the causal organism.
Hop Latent Viroid (HLVd) Suspicion
Hop latent viroid can infect cannabis and may be associated with reduced vigor, altered morphology, poor rooting, or reduced flower/resin performance. Symptoms are variable and visual inspection cannot confirm infection.
Damping-Off & Seedling Collapse
Seedling collapse near the media surface can involve pathogenic fungi or oomycetes, but excessive moisture, poor aeration, weak seedlings, temperature, and mechanical injury can create similar outcomes or increase disease risk.
Use the same evidence rule for every profile.
Record what you actually see, compare look-alikes, collect evidence that can separate them, and recheck after any intervention. Presence of an organism does not automatically prove it caused every symptom on the plant.