Entomosporium Leaf Spot on Red Tip
Disease Information Note 11
Ronald K. Jones, Plant Pathologist (retired)
Mike Benson, Plant Pathologist
[General Information] [Symptoms]
[Disease Cycle] [Control]
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caused by the fungus Entomosporium maculatum, is a widespread and
destructive disease of red
tip (Photinia fraseri), loquat (Eriobotrya japonica),
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.
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.
leaf spot on red tip.
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.
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.
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.
fungicides may also be help in the management of leaf spot in the landscape.
Recommended for Entomosporium Leaf Spot Control
per 100 gallons
- 1.0 lb.
**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.
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Because environmental conditions and methods of application by growers may
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Recommendations for the use of chemicals are included in this publication
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