What Pest Is This?
Use this to narrow down what you are seeing and jump straight to the right pest page. Keep it simple. Pick the most repeatable symptom, not every small imperfection.
Before you spray: take a clear photo, check the underside of leaves, and use a hand lens if you have one.
This is a guide, not a lab test. If you are unsure, start with scouting and prevention first.
Read the full pest and disease guide as text
Every pest and disease the tool above can identify, grouped by the symptom you are most likely to notice first. If you already know what you are looking at, go straight to that guide. If you are not sure, use the tool, or start with pests and diseases fundamentals.
What causes silver streaks or fine speckling on cannabis leaves?
Silver streaks and scraped looking leaf surfaces usually point to thrips. Fine pale speckling that gets worse over time, with webbing showing up later, usually points to spider mites. Check leaf undersides and new growth first for both.
Thrips
Silver streaks and scraped looking leaves. Check undersides and new growth first.
Where to look: top of the canopy and new growth.
Spider Mites
Speckling that gets worse over time. Webbing shows up later. Warm, dry zones are common hotspots.
Where to look: leaf undersides, starting in warm dry corners and near intakes.
What causes sticky residue on cannabis leaves?
Sticky residue on leaves is honeydew, which means a sap feeding insect is present. Aphids and whiteflies are the usual causes above the soil line. If the plant is also stalled and feeding does not help, check the root zone for root aphids.
Aphids
Clusters on tender growth and leaf undersides, plus sticky honeydew.
Where to look: new growth at the top of the plant and leaf undersides.
Whiteflies
Small white insects that lift off when disturbed. Check undersides for immature stages.
Where to look: leaf undersides, with adults flying up when the plant is moved.
Root Aphids
Plants look hungry and stalled no matter what you feed. Check the root zone and runoff areas.
Where to look: in and on the growing media, around drainage holes and runoff.
What causes twisted or bronzed new growth on cannabis plants?
New growth that looks twisted, hardened, or bronzed is the signature of russet and broad mites. This one is often misread as a nutrient problem at first, because the mites themselves are too small to see without magnification.
Russet and Broad Mites
New growth looks twisted, hardened, or bronzed. Often misread as a nutrient issue at first.
Where to look: the newest growth at the top of the plant.
What is the white powdery coating on my cannabis leaves?
A white powdery coating on leaf surfaces is powdery mildew. It spreads fast in dense canopies with poor airflow and stable humidity, and it can move onto buds if it is left alone.
Powdery Mildew
White powdery spots that can spread fast in dense, humid microclimates.
Where to look: lower and mid canopy first, then buds if pressure builds.
What causes tan or brown spots on cannabis leaves?
Distinct tan or brown leaf spots that start on lower leaves and move upward are usually leaf septoria. It tends to appear when conditions stay wet and leaves do not dry out between waterings or rain.
Leaf Septoria
Tan or brown leaf spots, usually starting low and moving up if conditions stay wet.
Where to look: lower leaves first, working upward.
Why are my cannabis buds turning brown and mushy from the inside?
Buds that brown and go mushy from the inside out are botrytis, also called bud rot. It is driven by humidity, bud density, and weak airflow, and dense flowers can hide it until the damage is well advanced.
Botrytis (Bud Rot)
Buds browning from the inside out, usually tied to humidity, density, and airflow.
Where to look: inside the densest buds, opening a suspect cola to check the core.
What is chewing holes in my cannabis leaves and buds?
Clearly chewed tissue, along with frass, means caterpillars or budworms. The chewing damage matters less than what follows it, because tunneling into dense flowers often opens the door to rot.
Caterpillars and Budworms
Chewed tissue, frass, and bud damage. Often leads to rot in dense flowers.
Where to look: on and inside buds, and anywhere leaves show chewed edges or holes.
What are the tiny flies around my cannabis pots?
Tiny flies hovering around pots, media, or drains are almost always fungus gnats. The adults are the visible part, but the damage is done by larvae in wet media, so watering habits are the first thing to correct.
Fungus Gnats
Adults hover around pots. The real issue is larvae in wet media. Fix watering first. Shore flies look similar but signal algae and standing water rather than root feeding.
Where to look: the media surface, drainage trays, and lower leaves.
Why is my cannabis plant wilting even though I am watering it?
Wilting that does not respond to watering points at the root zone. Pythium is tied to wet media and low oxygen, fusarium causes a sudden wilt that does not respond to water or feed, and root aphids cause plants to stall as though underfed.
Pythium (Root Rot)
Wilting with wet media and compromised roots. Oxygen and irrigation habits matter here.
Where to look: the root zone and the growing media.
Fusarium
Sudden wilt that does not respond to water or feed. Often tied to vascular infection.
Where to look: whole plant wilt, with stems and roots checked for discoloration.
Why are my cannabis seedlings collapsing at the soil line?
Seedlings that collapse at the soil line are showing damping off. Propagation moisture and cleanliness are the levers that prevent it. Pythium can produce similar losses in very young plants.
Damping Off
Seedlings collapse at the soil line. Propagation moisture and cleanliness are the levers.
Where to look: at the soil line on very young plants.
Before you treat anything, take a clear photo, check the underside of leaves, and use a hand lens if you have one. If two options still feel close, start with scouting and environment corrections before reaching for stronger tools. For the fundamentals, see pests and diseases.
