Entomosporium Leaf Spot Diagnostic Guide
Leaf spot, caused by the fungus Entomosporium maculatum, is a widespread and destructive disease of red tip (Photinia fraseri), loquat (Eriobotrya japonica), India hawthorn (Rhaphiolepis indica), some pear cultivars (Pyrus sp.), and several other members of the rose family. This disease is most damaging to plants in the landscape and nurseries during periods of cool, wet weather and when active growth is occurring. Low levels of leaf spot are usually purely aesthetic. Severe infections can result in early and heavy leaf drop. Heavy leaf drop severely reduces the landscape value of red tip and can cause plant death.
Trees at Risk
Indian hawthorn, red tip photinia, loquat, and pear species.
Affects trees throughout SE and the southern US.
Red Tip Photinia
Signs of Damage
- Tiny, circular, bright red spots on both the upper and lower surfaces of young expanding leaves are the first symptoms.
- Numerous small spots may coalesce into large maroon blotches on heavily diseased leaves.
- Leaf spots on mature leaves have ash brown to light gray centers with a distinctive deep red to maroon border.
- Tiny black specks, spore-producing bodies of the fungus, can often be observed in the center of each leaf spot.
- Spots similar to those on the leaves can develop on leaf petioles and tender stem growth during prolonged periods of cool, wet weather.
Looks like many other leaf spot diseases, may also be mistaken for thrips damage.
Masses of spores are released during periods of wet weather from the fungal spore producing structures in the center of the spots from late winter through much of the year except during the hot periods of summer. These spores are spread to healthy foliage by a combination of splashing water and wind. New leaf spot symptoms appear within 10-14 days after a wet infection period.
Field diagnosis of the diseases and the host plant are usually sufficient. Collect leaf samples and submit to a local extension for a definite diagnosis.
Provide adequate fertilizer and water. Avoid overhead irrigation, and/or water early in the day. Avoid excessive pruning of hedges. Rake and dispose of fallen leaves offsite.
Other Treatment Practices
- Irrigate once a week during extended drought periods. Do not use overhead irrigation: use drip or trickle irrigation instead to keep the foliage from getting wet.
- Mulch is very beneficial for all trees because it reduces competition with turf and moderates soil temperature and moisture levels. Maintain a 2-3 inch deep layer of composted mulch over the root zone.
- Rake and dispose of fallen leaves offsite.
Treatment Strategy Expectation
Entomosporium will always be present in the landscape, and treatment must focus on suppression, not eradication.
A Diagnostic Guide is designed to help you identify a pest issue and management solutions. Always refer to product label for all rates and approved uses. Some images courtesy forestryimages.org. Use of the images does not imply endorsement of treatments by forestryimages.org