Sycamore trees are one of the most popular ornamental trees in the world. They grow in many different climates and habitats. The genus Sycamea includes over 600 species worldwide, with the largest number found in North America (Saccamyrma). There are several subspecies of Saccamyrma, but all belong to the genus Sycamea. Most species have yellow or white flowers, which vary greatly in size and shape depending on their age. Some species produce only male flowers; others produce both female and male flowers at the same time.
The genus Sycamea contains approximately 200 species of trees, shrubs, and herbs. Many of these plants are used medicinally, especially for treating coughs and colds.
Others are cultivated for their wood products such as plywood, veneer, and paper. Trees grown commercially include ash, birch, cherry, elm, hickory, maple (Alnus), oak (Quercus), pine (Pinus), poplar (Populus) and willow (Salix).
Symptoms of Sycamore Tree Disease:
Symptoms of sycamore tree diseases usually appear after years of neglect. They can also emerge when the soil is disturbed during construction or planting.
The most common symptom of a diseased tree is the loss of leaves. This occurs during different times of the year, depending on the disease.
Drought stress: Trees begin dropping leaves in late summer or early fall. There may not be any other symptoms except for dead patches of grass in the tree’s root zone.
Borers: During severe infestations, trees begin dropping leaves in the spring. Dead branches found at the top of the tree may also be a sign of borers (beetle larvae).
Woodpeckers may appear at the base of the tree, pecking around randomly.
Vascular wilt: A fungal disease that gradually clogs the supply of water and nutrients to the foliage and roots of trees. Becomes apparent during rainy weather or during periods of drought.
Trees that are under stress due to other reasons (such as construction) are most susceptible.
Canker: Fungal disease that causes dead spots on the leaves and eventually kills them. After several years, cankers girdle and kill the trunk of the tree.
Leaf scorch (Sycamore anthracnose): Can be identified by brown spots on the leaves which later turn yellow and fall off. Underneath the spots are veins that become prominent, hence the name “leaf scorch.” These brown or black spots may merge to form large blotches on all the leaves.
The disease affects both wild and cultivated trees.
Sycamore bark disease: Rarely kills trees but causes unattractive, dead stripes on the trunks. Lesions are 1 to 2 inches wide and may be several feet long.
Girdling roots: Dead, thin brown strips of bark encircle the trunks of infected trees. Trees more than 6 inches in diameter are not affected.
This disease is common in newly planted trees and can be prevented by planting at the correct depth.
Trees can also become diseased from contact with infected seedlings or stumps that have not been completely cut through.
Control of sycamore tree diseases:
There is no cure once a tree is infected. Most sycamore tree diseases are spread by insects or fungi.
Therefore, the key to disease control is to keep the trees healthy. The following practices will help to maintain a healthy tree:
Plant trees in sites with good air circulation (such as on a hilltop).
Choose an appropriate nursery tree.
Choose a disease-resistant species or cultivar.
Avoid wounding the tree during planting.
Water the tree during dry spells.
Keep weeds and grass away from the base of the tree, as they compete for water and nutrients.
Maintain a 3- to 4-foot-deep layer of leaves or other organic mulch around the base of the tree. This layer will protect the tree from drying winds and droughts, and it will also keep competing weeds from stealing water and nutrients.
Do not plant the tree in a low spot where it may become waterlogged.
Trim tall trees regularly to promote strong root growth.
If greens are harvested from the tree, wait until after they have been mowed twice to prevent nitrogen deficiency.
Buy only certified disease-free trees.
Do not plant trees too close together or allow any branches to intertwine, which promotes the spread of disease. Leave at least 6 feet between trees.
Do not put diseased trees in piles of chipped trees for use as mulch. Chips from infected trees can carry fungal spores that will infect other trees.
Prune branches at least 6 feet above the ground, and remove all pruned wood from the area to prevent further disease spread.
Deeply planted trees are more resistant to borers, but they also become more susceptible to other tree diseases.
Include a 3- to 5-year supply of tree planting stock in your emergency preparedness plan.
Special case: Honeylocust tree borers
Honeylocust trees are very susceptible to borer infestations. If borers are found in the trunk, immediately look for exit holes by carefully brushing the bark.
Check the entire circumference of the trunk. If borers are present, they will have exited the tree within 2 or 3 feet of each other.
The borers re-infest an area much faster than they leave it. They do not fly or jump.
They crawl only a short distance so all new infestations begin within 100 feet of an existing infestation. It is critical to immediately find and destroy all nearby infected trees to keep borers from spreading.
Trees within 100 feet of the infected tree must be examined for borers. Check trees for exit holes or galleries by gently running your hand over the bark.
Be careful not to mistake sawdust from emerging moths for exit holes. Examine the lower trunk first. If borers are present, they will have left the tree within 2 or 3 feet of each other.
If borers are detected, mark the tree. Check all surrounding trees within 100 feet for telltale exit holes or sawdust.
If you find any additional infested trees, mark them and begin again by looking at all trees within 100 feet of those trees. The procedure is repeated until no more infested trees are found. All infested trees must be treated to prevent re-infestation.
Borers may also be detected by tapping on the trunk with a stick. If you hear a hollow sound, borers may be present.
The tree should be cut open to determine if borers are present.
Thoroughly inspect trees in late summer or fall, before the moths emerge.
Treat all infested trees immediately after detection to prevent re-infestation.
Treat each infested tree as soon as possible with an appropriate insecticide. Injecting the trunk with a soil drench is the most effective method for treating borers.
After treatment, cut out all exit holes and remove infested wood. This can be used to make bee blocks for honeybee hive maintenance.
Purdue University and Indiana Department of Natural Resources
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Sources & references used in this article:
A guide to major insects, diseases, air pollution injury, and chemical injury of sycamore by TD Leininger – 1999 – books.google.com
Sycamore pests: a guide to major insects, diseases, and air pollution by TH Filer – 1977 – books.google.com
Chemical Management of Invasive Shot Hole Borer and Fusarium Dieback in California Sycamore (Platanus racemosa) in Southern California by JS Mayorquin, JD Carrillo, M Twizeyimana… – … disease, 2018 – Am Phytopath Society
Sycamore anthracnose. by D Neely – Journal of Arboriculture, 1976 – cabdirect.org
Quality and availability of food for a sycamore aphid population. by AFG Dixon – Animal populations in relation to their food resources., 1970 – cabdirect.org
Insecticidal properties of bistrifluron against sycamore lace bug, Corythucha ciliata (Hemiptera: Tingidae) by C Yoon, JO Yang, SH Kang, GH Kim – Journal of pesticide science, 2008 – jstage.jst.go.jp