The leaves of cannabis are distorted
This may be caused by the following factors; a high-temperature environment, excessive light, or a lack of nutrition. To avoid these problems and achieve consistent growth, you should use a plant growth regulator.
SYMPTOMS
Leaves pucker and distort. Leaves are coated with a clear, sticky, varnishlike substance on which gray-black mold grows. The plant may wilt and die. Look for small, pear-shaped insects with two “tailpipes” on their rear ends clustered 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
Leaves surrounding buds are curled into a pouch and sewn shut with silk. A caterpillar or its pupa is inside the bag. Leaves are skeletonized (soft tissue eaten away, leaving veins).
DIAGNOSIS
leaf-eating caterpillars and budworms: European corn borer (Ostrinia nubilalis); hemp borer, leaf roller, or hemp seed eater (Grapholita delineate); cotton bollworm (Helicoverpa armigera); corn earworm (Helicoverpa zea); flax noctuid (Heliothis fireplace); hemp bagworm (Psyche cannabinella); silver Y moth (Autographa gamma); dot moth (Melanchra persicaria); cabbage moth (Mamestra brassicae); garden tiger moth (Arctia caja); common hairy caterpillar (Spilosoma obliqua); beet webworm (Loxostege sticticalis); hemp dagger moth (Plataplecta consanguine)
SOLUTIONS
• Weed
• Use screens on doors, vents, and windows
• Use cutworm collars
• Turn off lights at night
• Remove pests by hand
• Use beneficial insects
• Use beneficial nematodes
• Use beneficial bacteria
• Use beneficial protozoa
• Use insecticidal viruses
• Use hot-pepper spray
• Use garlic spray
• Use insecticidal soap
• Use neem
• Use spinosad
• Use pyrethrin
• Do not plant near corn (maize)
• Rotate crops
SYMPTOMS
Leaves curl up. Silvery white or yellowish speckles and streaks appear on leaves. Black specks that look like ground pepper cover plants. Plants may wilt and die.+
DIAGNOSIS
thrips: onion or tobacco thrips (Thrips tabaci), greenhouse thrips (Heliothrips haemorrhoidalis), marijuana thrips (Oxythrips cannabis), Indian bean thrips (Caliothrips indices), western flower thrips (Frankliniella occidentalis)
SOLUTIONS
• Sanitize
• Use screens on doors, vents, and windows
• Use traps
• Use beneficial insects
• Use beneficial mites
• Use kaolin
• Use insecticidal soap
• Use neem
• Use spinosad
SYMPTOMS
Leaves become twisted and distorted. Leaves soon turn brown and drop off the plant. Undistorted leaves have angular yellow spots that vary in size (spots confined by leaf veins). Look for grayish velvety fuzz on the undersides of the leaves.
DIAGNOSIS
downy mildew (Pseudoperonospora cannabina, P. humuli)
SOLUTIONS
• Sanitize
• Weed
• Mulch
• Filter the air
• Move the air
• Use beneficial bacteria
• Use baking soda spray
• Use copper
• Plant polycultures
• Choose genetically resistant plants
• Rotate crops
• Create healthy soil
• Decrease nitrogen
• Keep foliage dry
SYMPTOMS
Leaves are distorted and twisted, with curled margins and hooked tips. Plant growth stunted. Stems are thin, brittle, stiff, and break easily.
DIAGNOSIS
calcium (Ca) deficiency
SOLUTIONS
• Create healthy soil
• Measure and modify pH
• Manage essential nutrients
SYMPTOMS
Leaves twist and become deformed, then turn yellow, and may exhibit gray specks. Apical buds (at the top of the plant) and lateral buds in leaf axils (where the leaf attaches to the stem) turn brown and die.
DIAGNOSIS
boron (B) deficiency
SOLUTIONS
• Create healthy soil
• Measure and modify pH
• Manage essential nutrients
SYMPTOMS
Young leaves at branch tips twist and deform, turn pink, grow very pale, and then wither.
DIAGNOSIS
molybdenum (Mo) deficiency
SOLUTIONS
• Create healthy soil
• Measure and modify pH
• Manage essential nutrients
SYMPTOMS
Leaves grow abnormally in size and shape and are deformed. Leaves also have odd yellow markings resembling virus infection. The plant is stunted and may die.
DIAGNOSIS
herbicide damage
SOLUTIONS
• Stop using herbicides
• Move affected container plants indoors