Photinias are a beautiful species of evergreen shrubs and small trees known for their attractive fruit and colourful foliage. However, photinias are prone to a fungal leaf spot known as diplocarpon or entomosporium. Treatment for this defoliating plant problem is most often as simple as spraying the photinia with a fungicide that contains liquid copper.
Causes of Photinia Fungal Leaf Spot
Fungal leaf spot on photinia is caused by fungal spores that spread to the leaves of the plant. The fungal spores are often spread by splashing water on another plant that contains the spores. The spores are also spread by overwintering on the fallen leaves of plants. Careful watering and effective removal of fallen leaves in the winter can help reduce outbreaks of fungal leaf spot on photinia.
Fungal leaf spot is usually not fatal for photinia unless the infection is severe. Tiny red or purple spots on the tops of the leaves are a sure sign of fungal leaf spot. The spots can enlarge and turn white or grey in the middle as the infection progresses. Usually the fungal spotting will only cause aesthetic damage to the plant but if severe enough, the fungus can cause extensive leaf drop (called defoliation) that negatively affects the photinia's health.
Liquid copper fungicides are preventive in nature. Essentially, this means that liquid copper fungicide will not actively combat the existing fungus but it will help to stop the spread of the fungus. Because copper fungicide is a preventive measure, many gardeners and landscapers spray their photinia with it during the spring, as the shoots emerge, in preparation for later season problems. Copper fungicides are available in several forms, including pellet, powder and, of course, liquid.
Benefits and Drawbacks
Liquid copper fungicides have a specific advantage to other forms of copper fungicides, namely with ease of use. Liquid copper fungicides are sprayed onto the leaves of the plant using an attached ready-to-use system or, as a concentrate, mixed with solution and applied with a sprayer. The drawback of a liquid copper fungicide is that you will inevitably use more than you really need to control the problem. Apart from being costly, excessive application can also be detrimental to the environment if allowed to accumulate in the soil.
Apart from spraying with a liquid copper fungicide, gardeners can also control and prevent the spread of fungal leaf spotting on their photinias through proper landscape management. Fungi spread and develop in high humidity, low sunlight and poor air-circulation areas. Thus, gardeners should provide good air circulation by removing underbrush and spacing photinia plantings properly. Additionally, if the photinia are planted in a shadier environment, gardeners should be vigilant for appearance of the fungal spotting and avoid overwatering.