Camellia leaf blight / RHS Gardening (2024)

FAQs

Camellia leaf blight / RHS Gardening? ›

Camellia leaf blight is a disease that can be caused by two fungal pathogens: Monochaetia karstenii or Pestalotiopsis species. The development of the disease is favoured by wetness on the leaves and any factors that weaken or damage the foliage.

Apply fungicides: Apply a fungicide as a preventative measure before the flowering season starts or at the first sign of the disease. Fungicides containing active ingredients such as copper, thiophanate-methyl, and mancozeb can be effective in controlling camellia flower blight.

Fungicide sprays recommended for the flowers include mancozeb. Application of soil drenches, such as mancozeb or captan, around the plant every 2 weeks from late December through January may be helpful in reducing the intensity of disease.

Give your camellia a well-drained soil and adequate water and nutrients can prevent browning. Plant your Camellia in a location where they receive partial shade. Check the condition of your Camellia regularly and adjust these as once your leaves start browning there is no turning back.

Feeding Your Camellia

As they prefer to be grown in an acid soil, camellias have a high magnesium requirement and once a year Epsom salt (a tablespoon to a gallon of water) can be given along with topdressing the soil with cottonseed meal (about a ½ inch sprinkled on the top of the soil).

When algal leaf spot is severe, copper fungicide sprays are recommended. Sprays may need to be applied every 2 weeks if wet conditions persist. However, when the affected plant is too tall to apply sprays safely, treatment may not be feasible for the homeowner and may require professional assistance.

Infection by the Ciborinia camelliae fungus initially causes small, brown, irregularly shaped blotches in petals. Spots enlarge rapidly until the entire flower is brown and dead. Except when wet, blighted petals are dry or leathery but do not crumble when handled.

Use coffee grounds as mulch for acid-loving plants — roses, azaleas, rhododendrons, evergreens, hydrangeas and camellias. They like coffee grounds for the natural acidity and nutrients they add to the soil. Sprinkle coffee grounds around areas of ant infestation to deter them.

If the whole plant appears dead, cut hard back to 10 cm from the ground and give it till autumn to regenerate - which it will do if the roots are healthy. If you have a camellia in a pot, it is vital to stop the roots freezing. Wrap the pot in bubble wrap or bring it indoors in cold weather.

Be sure to cut off all of the infected leaves because they will not recover. I know a horticulturalist who frequently repeats the phrase, “Bad leaves never turn into good leaves.” It is advice worth remembering. A: There is no way I would contradict a certified arborist, Julia.

Should I remove leaves with blight? ›

Treating Blight

Once blight is positively identified, act quickly to prevent it from spreading. Remove all affected leaves and burn them or place them in the garbage. Mulch around the base of the plant with straw, wood chips or other natural mulch to prevent fungal spores in the soil from splashing on the plant.

Chemical methods

Spray Streptomycin sulphate + Tetracycline combination 300 g + Copper oxychloride 1.25kg/ha. If necessary repeat 15 days later.

Treat with a miticide, like Natrasoap, it is really easy to mix following the directions, make sure you thoroughly cover both sides of the leaves. Then feed the plants to encourage lots of healthy new growth. A final tip that could help stop this pest from taking hold.

Galls should be removed and destroyed as soon as they are seen. Repeat infection is less likely if this can be done before the bloom of spores develops on the gall. If spores are already present it would be worth enclosing the gall in a plastic bag before removing it.

If your camellia does die back, cut back to healthy growth. If the whole plant appears dead, cut hard back to 10 cm from the ground and give it till autumn to regenerate - which it will do if the roots are healthy. If you have a camellia in a pot, it is vital to stop the roots freezing.

Black vine weevil (Otiorhynchus)

So, if you see leaf feeding, it is highly likely that the soil in the pot is also infested with black vine weevil larvae. For control: Normally, weevils cause only damage that your camellia can compensate for well in a healthy state.