Entomosporium Leaf Spot on Red Tip

Ornamental Disease Information Note 11
Ronald K. Jones, Plant Pathologist (retired)
Mike Benson, Plant Pathologist






[General Information] [Symptoms] [Disease Cycle] [Control]
[Back to Ornamental Disease Notes] [Other Resources]

General Information

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.

Symptoms


Entomosporium leaf spot on red tip.
Tiny, circular, bright red spots on both the upper and lower surfaces of young expanding leaves are the first symptoms of Entomosporium leaf spot. 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.

Low levels of leaf spot usually cause little more than cosmetic damage but maintain a source of spores for future infections. Severe infections, however, often result in early and heavy leaf drop. Heavy leaf drop severely reduces the landscape value of red tip and can cause plant death. Some cultivars of India hawthorn are as severely affected as red tip.

Disease Cycle

Spots on the leaves and young shoots are important in the survival of the Entomosporium leaf spot fungus. Fallen, diseases leaves are less important sources of the fungus. 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.

Control

For the landscape, purchase plants showing no leaf spot symptoms. Isolated healthy plants or hedges can often remain healthy as the spores are only splashed over short distances. Space plants to improve the air movement around the plants and promote rapid drying of leaf surfaces. If it is necessary to irrigate the plants, do not wet the foliage or irrigate in midday to reduce the period of time foliage remains wet. If possible, remove fallen diseased leaves. Do not water or fertilize plants any more than necessary to avoid promoting excess new growth. Also, reduce pruning during the summer which promotes continual new growth. Severely defoliated plants may need to be pruned heavily to have a small, easier to spray plant, to reduce the source of spores and improve air movement. It may be necessary to remove severely diseased plants that have also been damaged by cold injury and replace them with another plant species that is not susceptible to leaf spot.

Several fungicides may also be help in the management of leaf spot in the landscape.

Fungicides Recommended for Entomosporium Leaf Spot Control

Fungicide Rate per gallon Rate per 100 gallons
Banner 1 tsp. 12-20 fl. oz.
Daconil 2787 75W* 1 1/2 tbs. 1 1/2 lb.
Daconil 2787 4.1F 2/3 tbs. 2 pt.
Chlorothalonil* see label see label
Fore 80W 3/4 tbs. 1 1/2 lb.
Bayeleton 25W** 2 tsp. 1/2 - 1.0 lb.
Funginex EC* see label see label

*Available in small packages.
**Repeated applications may cause some injury.

This disease is very difficult to control after plants are severely infected. During extended cool, wet periods, protective sprays may be necessary. Where leaf spot is a problem, applications of one of the above fungicides should begin as new growth starts in the spring with additional sprays at 10 - 14 day intervals until mid-June. Make applications at 10 day intervals during cool, wet periods and at 14 day intervals during drier periods. Fungicide applications should not be necessary during hot, dry periods. It may also be helpful to make 3-4 applications from mid-October to late November if wet weather prevails.

Other Resources

Plant Disease Information Notes Home Page
HIL-636 Shrubs 8'+ for North Carolina Landscapes or PDF version of HIL-636
Horticulture Information Leaflets Home Page
North Carolina Insect Notes
North Carolina Agricultural Chemicals Manual
NCCES Educational Resources

For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service personnel.

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Recommendations of specific chemicals are based upon information on the manufacturer's label and performance in a limited number of trials. Because environmental conditions and methods of application by growers may vary widely, performance of the chemical will not always conform to the safety and pest control standards indicated by experimental data.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical. For assistance, contact your county North Carolina Cooperative Extension Service agent.

Published by North Carolina Cooperative Extension Service Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

Webpage reformatted Dec. 2000 by A.V. Lemay