George Sundin, Michigan State University Extension, Department of Plant, Soil, and Microbial Sciences, and Nikki Rothwell, Michigan State University Extension - Cherry leaf spot is the most important fungal disease of tart cherries in Michigan. Leaves curl and become yellow and purple or reddish spots appear on the leaves followed by holes developing in foliage. Placing a layer of straw under the trees can also help stop spoors from moving up from the ground into the tree. X–disease Also known as cherry buckskin disease, this cherry tree disease is spread by a parasitic organism transmitted by leafhoppers. Spots gradually turn brown before the leaves turn yellow and drop, defoliating the tree. This information is for educational purposes only. Leaves and fruit drop from the tree, and fruit has a leathery, bumpy appearance and fails to ripen properly. This article was published by Michigan State University Extension. The latter attacks members of the Prunus family – such as cherries and plums, both edible and ornamental. At least two applications of chlorothalonil should be made before shuck split with the goal to minimize the potential of infection at this early timing. Cherry leaf spot is a bigger problem in the Eastern United States, but it can occur anywhere cherries grow. Remedies for Cherry Leaf Spot Disease The best protection against cherry leaf spot is good sanitation in the orchard. Leaf scorch is a noninfectious condition caused by an unfavorable environment - there is no virus, no fungus, no bacterium to blame. However, upon further examinations of infected trees, we found significant infection of these early forming bract leaves (Photo 2), and as we have been saying with early apple scab infection, these early infections can drastically jump-start an epidemic. We will hope for a good winter for your trees. To contact an expert in your area, visit, or call 888-MSUE4MI (888-678-3464). Spots gradually enlarge to about ¼ inch in diameter and turn reddish-brown. If you are growing cherry trees, you should know about cherry leaf spot, one of several fungal diseases that attack both cherry and plum trees. The spots begin to brown and fall, leaving a hole in the foliage. These are the new SDHI premixes Luna Sensation and Merivon and the strobilurin fungicide Gem. As with all other diseases, cherry leaf spot infection will rise to epidemic proportions under conducive weather conditions, and with less infection early, there will be less inoculum in the tree that growers will have to control during times with more optimal conditions for cherry leaf spot development. Infection happens as spores enter the leaves through the stomata on the underside of the leaf during damp conditions. This dead portion then falls out of the leaf leaving behind the hole. Wenn Sie die Anzeichen kennen und eine frühzeitige Behandlung durchführen, können Sie Ihre Ernte retten. The organism is then transferred up into the tree canopy and settles on the leaves. Trees that become infected early enough in the spring set fruit that fails to mature. Begin removing and destroying the dropped leaves at the understory. Later in the growing season, new spoors can develop on the leaves causing a secondary infection. However, this pathogen also attacks sweet cherry and plum trees. Hello. The cherry leaf spot fungus infects leaves through stomata, and these parts of the leaf structure are not open and functional until the first leaves are mature. Dr. Sundin's work is funded in part by MSU's AgBioResearch. Prior to shuck split, the recommended fungicide for cherry leaf spot management is chlorothalonil (Bravo and generics). Check out the MSU Agricultural Industries Certificate Program! The disease causes the part of the leaf that is affected to turn brown and die. This early defoliation can result in weak trees, and if we have a hard winter, trees may be at risk of winter injury. It’s critical to protect tart cherry trees early in the season from cherry leaf spot infection. Removing these leaves will reduce disease spores the next spring. Whitish-pink masses of sticky spores (conidia) form within the spots on the undersides of infected leaves during periods of damp weather (Figure 2). Die Flecken auf Kirschblättern sind leicht mit mehreren anderen Pilzkrankheiten zu verwechseln. Large portions of the tree can become defoliated during the growing season. The fungus grows most rapidly in temperatures between 60º to 68ºF (16º to 20ºC) and younger leaves are most at risk for becoming infected. Once fungal infection occurs in the tree, the fungus will produce tremendous spore numbers from lesions established on the leaves, and in most cases, there are usually more spores developing from lesions than ascospores that are coming up from leaves overwintering on the ground. I am not sure of the fungus, but it is likely cherry leaf spot, which causes cherry leaves to defoliate prematurely during the season. The tree will be more susceptible to winter damage, loss of fruit spurs, small fruit buds, decreased fruit size and yield, and eventually death of the tree occurs. It can not be helped by chemical control so you will have to discover the underlying causal factor which can be drying winds, drought, root damage and other environmental problems. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture.