Problems with camellias come in the form of diseases such as dieback and canker (most serious of camellia diseases), pests, and injury caused by improper environmental conditions. To successfully deal with problems with camellias, identify their particular susceptibilities and maintenance requirements, like a need for consistently moist, acid, well-drained soil for effective prevention and treatment.
Problems with camellias include susceptibility to certain diseases. Camellia dieback and canker, according to the Clemson University Extension, is the most serious disease. This fungal infection is created by the fungus Glomerella cingulata. Symptoms include yellowing and wilting of leaves, gray spots on bark and stems and cankers on stems (sunken areas) that eventually lead to the extreme loss of health and death. To prevent and treat dieback and canker, maintain your camellias for vigorous plants that are able to fight off disease. As treatment, prune back twigs below cankers and apply the fungicide thiophanate-methyl. Another disease-based problem with camellias is flower blight caused by the fungus Ciborinia camelliae that causes the display of brown spots on petals that spread over most of the flower. Within 48 hours, expect flower drop. Since the fungus lives in soil, keep mulch fresh and remove diseased parts. Apply the fungicidal spray mancozeb or triadimefon, as suggested by the Clemson University Extension.
Pests are a damaging problem with camellias. Scales make up the most prominent insect pest that injure camellia flowers. Scale is parasitic, extracting sap mainly from leaves. The removal of nutrients diminishes the health of the camellia plant, and symptoms may also include yellowing of leaves, a decrease in the amount and size of blossoms and leaf drop; scales occasionally create a fatal infestation. To treat mild infestations, remove diseased parts of the plant as well as the insects by scraping them from the camellia; for severe problems, apply a spray horticultural oil during the spring season when the camellia has bloomed. Clemson University Extension suggests two applications; spray when weather is between 40 and 85 degrees Fahrenheit and repeat application after 10 days.
Many problems with camellias simply stem from improper environmental conditions. Bud drop causes buds to fall from the plant as well as the browning of younger buds. Often caused by extreme changes in temperature or moisture, or nutrient-deficient soil, keeping your camellias in their required conditions is the best course of action. Camellias may also suffer from the problem of sunscald if placed in locations with too much direct sunlight; the Clemson University Extension recommends keeping camellias in shaded areas to prevent scorched leaves and the potential infections that arise with injured camellias.