Pest control on cannabis plants
Insect pests like aphids, spider mites, or whiteflies can damage the leaves of your cannabis plants. To find out how to identify and treat these bugs, visit our guide to common cannabis pests.
When small pests are found in the walls or on the cannabis leaves, you may have to go a step further. The steps to take would be similar for many types of pests so we’ve included a few tips that might help control your problem.
Pest control on cannabis plants can be difficult depending on the type of infestation you’re dealing with. We’ll help you identify, understand and treat every plant pest known to man
Inspect the entire plant, especially under the leaves. Look for pests and the damage they do to your plants. Sometimes, a plant can be infested with these pests without even seeing them. Small holes in leaves can be signs of damage from pests such as thrips and spider mites. Leaves turning yellow or brown could be a sign of pests eating them from the inside out.
It is common when insects are present, they will go unnoticed until the population has multiplied. Once you see a pest problem it is likely to be a serious one. The leaves are where they are most active and easy to spot, so make your observations there.
SYMPTOMS
Small, pear-shaped insects with two “tailpipes” on their rear end cluster on the undersides of leaves. They can be any color. Ants may also be present; they bring and protect aphids.
DIAGNOSIS
aphids: green peach aphid (Myzus persicae), black bean aphid (Aphis fabae), hops aphid (Phorodon humuli), hemp louse (Phorodon cannabis)
SOLUTIONS
• Sanitize
• Use screens on doors, vents, and windows
• Use traps
• Use beneficial insects
• Use beneficial fungi
• Use kaolin
• Use hot-pepper spray
• Use insecticidal soap
• Use neem
• Use horticultural oil
If there are ants:
• Use traps
• Use diatomaceous earth
SYMPTOMS
A cloud of tiny, bright white insects flies up when plants are disturbed. Insects cluster on leaf undersides. Leaves turn yellow and wilt. Leaves are coated with a clear, sticky, varnishlike substance on which gray-black mold grows.
DIAGNOSIS
whiteflies: greenhouse whitefly (Trialeurodes vaporariorum), sweet potato or tobacco whitefly (Bemisia tabaci), silverleaf whitefly (Bemisia argentifolii)
SOLUTIONS
• Sanitize
• Use traps
• Vacuum adult insects from the air
• Use beneficial insects
• Use beneficial mites
• Use beneficial fungi
• Use garlic spray
• Use insecticidal soap
• Use neem
• Use horticultural oil
• Use pyrethrin
• Do not plant near eggplant, sweet potato, tobacco, or cotton
SYMPTOMS
You see tiny beetles that hop like fleas on leaves. You also find numerous small holes between leaf veins. Leaves may be skeletonized (soft tissue eaten away but veins remain).
DIAGNOSIS
flea beetles: hemp flea beetle (Psylliodes attenuate), hops flea beetle (Psylliodes punctulata), striped flea beetle (Phyllotreta nemorum), others (Podagrica spp.)
SOLUTIONS
• Sanitize
• Weed
• Use traps
• Use beneficial nematodes
• Use beneficial bacteria
• Use hot-pepper spray
• Use garlic spray
• Use insecticidal soap
• Use neem
• Use spinosad
• Rotate crops
• Do not plant near eggplant
SYMPTOMS
You see black beetle-like insects with long snouts on leaves. Leaves have holes in the middle or notches on the edges. Each hole or notch is surrounded by a yellow halo. When disturbed, pests drop to the ground and play dead. They often hide in the soil.
DIAGNOSIS
weevils and curculios: hemp weevil (Rhinoncus pericarps), cabbage curculio (Ceutorhynchus rapae)
SOLUTIONS
• Sanitize
• Weed
• Use row covers
• Remove pests by hand
• Use beneficial nematodes
• Use hot-pepper spray
• Use garlic spray
• Use insecticidal soap
• Use neem
• Use diatomaceous earth
• Use spinosad
SYMPTOMS
Extremely small bugs, barely visible to the naked eye, crawling on leaves. Fine silk webbing covers leaves, which are speckled with tiny yellowish dots.
DIAGNOSIS
mites: two-spotted spider mite (Tetranychus urticae), carmine spider mite (Tetranychus cinnabarinus), hemp russet mite (Aculops cannabicola)
SOLUTIONS
• Sanitize
• Use beneficial insects
• Use beneficial mites
• Use beneficial fungi
• Use kaolin
• Use insecticidal soap
• Use neem
• Use horticultural oil
• Manage humidity
SYMPTOMS
Small, wedge-shaped insects on the undersides of leaves jump and fly away rapidly when disturbed. Leaves are speckled with tiny whitish to yellowish dots and become coated with a clear, sticky, varnishlike substance, on which gray-black mold grows. The plant may wilt.
DIAGNOSIS
leafhoppers: glasshouse leafhopper (Zygina pallidifrons), red-banded leafhopper (Graphocephala coccinea), potato leafhopper (Empoasca fable)
SOLUTIONS
• Sanitize
• Weed
• Use row covers
• Use screens on doors, vents, and windows
• Use beneficial insects
• Use beneficial fungi
• Use insecticidal soap
• Use neem
• Use pyrethrin