Plant Disease Alert: Entomosporium Leaf Spot
July 3, 2019
The intense heavy rains we’ve received over the past year have encouraged a big uptick in certain plant fungal diseases. Entomosporium leaf spot disease is one we are seeing run rampant this spring and summer.
Entomosporium leaf spot is a fungal disease caused by the fungus Entomosporium mespili and affects several common landscape plants here in North Texas. Indian Hawthorn and red tip photinia are particularly susceptible. Other host plants include ornamentals in the Rosaceae family like quince and pear.
The fungus is spread by splashing water from rainfall or irrigation.
Entomosporium leaf spots spreads aggressively during the wet and cool spring and fall seasons, causing small, circular bright red to maroon spots on the surfaces of newly expanding leaves; the spots enlarge and turn grey as they age. On the highly susceptible photinia & Indian hawthorn, you will even see mass defoliation of plants which can eventually kill the plants. Once the usual hot & dry weather of summer hits, the fungus doesn’t spread as easily.
How to Slow the Spread of Entomosporium Leaf Spot:
- The fungus thrives in wet weather & needs moisture on leaves to spread. Allow plantings plenty of air movement and they are not planted too close together. You may need to remove excess plants if they were placed too close together.
- Water plants in the morning instead of the evening. This will allow leaves to dry faster. Or better yet - use drip irrigation so water does not unnecessarily splash on foliage.
- Remove & bag fallen diseased leaves from landscape beds. This will cut down on the amount of spores present & slow the rate of infection.
- Certain fungicides, like chlorothalonil, can slow the progression of Entomosporium. But, it will require multiple applications. You can also try natural copper fungicides to help suppress the disease.
- The best control method? Choose other plants besides Indian hawthorn or photinia for your landscape. If you love Indian hawthorn, we suggest Carissa or dwarf yaupon holly or perhaps try an abelia. A suitable replacement for a photinia hedge would be Nellie R. Stevens or Oakland holly.
If your trees and shrubs are on our SEASONS Bio-Fertilization Program, we can help address and treat specific plant diseases and pests.