Symptoms:
Leaf Colour:
Edges Appear Brown or Burnt
Pale Colour Leaves
Yellow Leaves - New Growth
Yellow Leaves - Lower, older leaves
Yellowing Between Veins
Dark or Purple Leaves
Black or Gray Patches on Leaves
Patches of white powder on leaves
Brown or Dark Spots
Mottling / Mosaic Pattern
Leaf Symptoms:
Upper Leaves / Newer Growth Affected
Lower Leaves / Older Growth Affected
Leaf Edges Appear Burnt
Leaf Tips Appear Burnt
Leaf Tips Die
Yellowing Between Veins
Patches of white powder on leaves
Red Stems
Spots
Mottling / Mosaic
Old Leaves Dropping Off
Slow Growth
Twisted Growth
Abnormal Growth
Leaves Curl Under
Leaves Curl Upwards
Wilting / Drooping
Webbing on leaves
Plant Symptoms:
Red or Purple Stems
Weak Stems
Old Leaves Dropping Off
Slow Growth
Twisted Growth
Leaves Curl Under
Leaves Curl Upwards
Plant Wilting / Drooping
Root Symptoms:
Slow Growing
Other Symptoms:
Webbing
Bugs
Mould
Buds Not Fattening
Spots on Leaves?: Yes
Unfortunately, bugs and other garden pests can totally mess up your marijuana harvest!
This page aims to be a comprehensive resource on the different types of bugs / pests / mould that can affect your marijuana crop, along with tips for preventing and solving each problem.
Pests that can affect your marijuana plants include aphids, fungus gnats, thrips, green flies, black flies, mosaic virus, spider mites, caterpillars, inchworms, whiteflies, white powdery mildew / white powdery mould, stem rot, and even mammals such as deer or cats!
Aphids
Barnacles / Scale Insects
Broad Mites & Russet Mites
Bud Rot or Mould
Caterpillars & Inchworms
Crickets
Fungus Gnats
Grasshoppers
Leafhoppers
Leaf Miners
Leaf Septoria / Yellow Leaf Spot
Mealybugs
Root Rot
Slugs / Snails
Spider Mites
Thrips
Tobacco Mosaic Virus (TMV)
Whiteflies / White fly
White Powdery Mould
It's time to fight back against cannabis bugs, mould and pests!
Quick Tip! Whenever you spray plants with anything, make sure to get the undersides of the leaves too, as this is where many pests like to hang out! A one-hand pressure sprayer / mister is also really helpful for spraying leaves.
Aphids
Aphids live under leaves & have different forms depending on their stage of life
Barnacles / Scale Insects
These bugs that look like barnacles and stick to the plant on stems and underneath leaves
Broad Mites or Russet Mites
These mites are so small you will likely never see them even under a magnifier. However, you can tell your plant has been infected because your new leaves will be blistered, twisted and glossy. The overall plant will also be growing poorly and if it's flowering the buds may turn brown. Broad mites and russet mites are often mistaken for other problems like nutrient deficiencies, heat stress or pH problems.
Bud Rot or Mould
When bud rot strikes, certain buds may start looking sickly overnight, with leaves turning yellow and/or bud becoming discoloured. When opened up the inside of the bud is dead or mouldy.
Caterpillars, Inchworms & Cabbage Loopers
Caterpillars and worms eat holes in leaves and leave droppings that look like black specks
Crickets
"Regular" crickets will munch on your leaves while "mole crickets" can tunnel under your plants and disturb their roots!
"Regular" Crickets
Mole Cricket - these can tunnel under your cannabis plants like moles
Fungus Gnats
Fungus gnats look like tiny dark flies. They hang around soil that stays wet for long periods of time, and their worm-like larvae crawl around in the wet top soil. Plants start getting sick if a gnat infestation gets out of control.
Grasshoppers
You've probably seen these before, but these seemingly harmless garden creatures will happily eat your cannabis leaves!
Leafhoppers
These bugs come in almost every colour known to man so sometimes it can be tough to tell what they are just from looking. However, they all make clusters of spots on your leaves where they've sucked out all the sap, so if you see spots like this you know you've got leafhoppers!
Leaf Miners
Leaf miners are larva that actually live inside your leaves and tunnel through them to eat!
Leaf Septoria / Yellow Leaf Spot
This fungus causes round yellow or brown spots, with symptoms often starting on lower parts of the plant
Mealybugs
These tiny white bugs look "hairy" and are found crawling on leaves and buds
Root Rot
Root rot is a common problem in hydroponic systems though overwatered plants in containers often display similar symptoms. Plants with root rot wilt and leaves may become discoloured. In the reservoir the roots turn brown, smelly and slimy.
Slugs / Snails
Slugs and snails usually come out at night, leaving holes in leaves which have scalloped edges from their individual bite marks. They also leave slime trails on leaves and on the ground.
Spider Mites
Spider mites are often caught from another grow room, and their bites leave small white speckles all over your leaves. They're so small they can be hard to see, though the best place to look is underneath leaves. You may see webbing if there's enough of them living on the plant.
Thrips
Thrips leave irregular bronze or silver marks that may look like "dried spit" or tiny snail trails. Their young look like fat, tiny worms.
Tobacco Mosaic Virus
It's not known whether mosaic virus has jumped from tobacco to cannabis plants, but in this article I'll share what I've learned so far...
Whiteflies/ White fly
Whiteflies look like tiny white moths and hang out under your cannabis leaves
White Powdery Mould
WPM leaves a white powdery substance that looks like flour or powder on leaves and stems
Discord
Links
