This week, I received a question from a concerned home gardener about a disease on red tip photinia. Before I saw the pictures included in the email, I had a good hunch about the culprit.
Red tip photinias became popular in the 1960’s as a privacy screen. This large shrub has beautiful spring color and can be found lining many fencerows in older homes. Unfortunately, red tip photinia faces a devastating disease issue called entomosporium leafspot.
Entomosporium leafspot is a fungal disease that affects woody ornamentals in the rose family. Indian hawthorne is another shrub impacted by entomosporium leafspot. This fungus does the most damage when we have frequent fall and spring rainfall, temperatures are between 60 and 80 degrees, and the plant is actively growing.
The first symptoms are bright red spots on the new leaves that can join to form large maroon blotches in heavily diseased plants. The fungus might just cause leaf drop in minor infections, but over time it can kill the whole plant.
If you have a light infection of entomosporium leafspot, you can help slow the spread by removing fallen leaves to reduce fungal spores. Try not to allow the foliage to remain wet, so water in the morning and use drip irrigation if possible.
New growth increases the susceptibility of the plant to infections, so limit pruning and excessive fertilizer to prevent a lot of new growth. Fungicides such as thiophanate-methyl and myclobutanil can be used when conditions are favorable for the disease. You have to time the application to cool, wet weather. Fungicides are not effective during hot, dry weather.
Unfortunately, entomosporium leafspot is destructive for red tip photinia and Indian hawthorn. If you have this fungus for long, you might consider removing the shrubs and replanting with other options. The “Grow Green: Native and Adapted Landscape Plants” guide has some great recommendations for our area of Central Texas. You can find it free online or at most local nurseries for purchase.
For more information about lawn and garden topics, contact County Extension Agent Kate Whitney at the AgriLife Extension Office at 512-943-3300.
