Any advise would be GREATLY appreciated. Proper pruning of Japanese maple is essential for tree health. The wood of affected plants shows a gray to olive-green streaking if the bark … May not injure silver maple. Japanese maples and maple species are very susceptible to this disease. Aphids often feed on leaves producing honeydew that encourages the growth of black sooty mold fungus on other leaves or on surfaces beneath the tree. My Japanese Maple of 15 year is loosing its trunk bark. Figure 2. An annual pruning of Japanese maple trees and shrubs to remove dead or dying branches and to keep the tree… I am not sure what to do or why this is happening. Important Notes: Chemical control of diseases and insect pests by sprays on large trees is usually not feasible since adequate coverage of the foliage with a pesticide cannot be achieved. Maple Tree Diseases. 2 Horticultural oil may injure Japanese, amur, and red maples. maple, cottony camellia, oleander, and cottony taxus scale. The bark over the canker becomes sunken, and reddish-brown sap oozes out. The female Japanese maple scale has an elongate, grayish white, waxy cover. Often triggered by a wet spring season, this fungal infection may spread on your Japanese maple tree… Various leaf spot diseases caused by fungal infection (like Phyllosticta and Septoria fungi) are found on Japanese maples, causing visible spots on the surface of leaves. Note the purple color of this life stage. Regardless of its color, when a maple's bark develops white spots, the tree may be fighting disease. Every summer we get a few questions about blemished or discolored leaves on Japanese Maples, which are most often symptoms of leaf scorch, a noninfectious disease or disorder that occurs most often after prolonged periods of dry and windy hot weather or bright sunshine, when the roots of a tree, especially young or recently planted trees which have yet to develop a substantial root system, … Infections capable of killing these plants tend to attack a tree’s internal systems, invading via the roots. Additionally, the clusters of white prunicola scale and white peach scale male's waxy covers give the host plant bark a white, woolly appearance. These types of health conditions generally affect the leaves, producing unsightly leaf spots and barren tree limbs. Of all the Japanese maple problems dead branches can be one f the most alarming. 1 Acephate may damage red and sugar maples. The majority of maple tree diseases are purely cosmetic and don’t threaten the life of the tree. Bleeding canker: Reddish-brown cankers develop in the inner bark of the main trunk and branches. Leaves wilt and branches die. Unsightly calluses and sunken areas on maple tree trunks and bark are caused by canker diseases. Leafhoppers and spittle bugs carry the bacteria from tree to tree. The short answer is the splits will not likely cause harm, but let's go in detail. Promote plant vigor by protecting the tree from stresses. Phytophthora cactorum Some varieties of Japanese maple (Acer palmatum, which grows in USDA zones 5b through 8), for example, have red, green or yellowish bark. I have put chicken wire around it for now to protect it and am thinking about using tree … The disease begins in bark layers, then extends into inner wood and often leaves oozing, wet areas on the bark. The inside of the tree at the base is fully exposed. Life History Close-up of a female beneath its waxy test. A: The problem of bark splitting on maples is a common one, especially in this part of the country. Common to maples, the fungal pathogens enter the trees through wounds. Verticillium is a soil fungal disease that can cause a wilting or dieback of branches and can lead to the tree dying.