Our Upstate Trees
Spring has sprung! Buds are rousing and leaves are forming; soon the fragrance of blossoms will fill the air. What kind of year can we expect from our trees? Most urban trees will continue to struggle due to the impacts of construction, girdling, poor species selection and improper installation. Topsoil stripping and compaction will continue to indirectly affect roots while directly affecting the life of our trees. Another drought will affect us all. What are some of the pests our trees may encounter this year?
Oaks & Sycamore: 2011 was a bad year for bacterial leaf scorch on pin oaks, white oaks and sycamore. You might have thought a mischievous boy painted your pin oak leaves half brown. Leaf scorch is spread by leafhoppers and spittle bugs. A late summer drought will exacerbate the problem. Watering and mulching will help. Severely infected trees can die without treatment, while spreading to other oaks, sycamores, maples, and other species. This probably won’t go away on its own.
Leland Cypress: Seirdium canker continues to spread from Leland to Leland across the South (as well as other conifers). Leland cypress has proven be a poor screen tree for our area (green giant is a better choice). A screen, which blocks an undesired view, as well as buffering sound and providing privacy, goes unnoticed as long as it does its job. But it has our attention when evergreen branches turn brown and holes start appearing in our screen. By that time the inner crown may already be severely infected with Seirdium canker, Botryosphaeria canker and blight. We have no effective fungicide.
Light to moderate outbreaks can be managed through stand thinning, pruning, mulching and irrigation by an arborist with experience in dealing with these stubborn fungi; owners and arborists usually are not aggressive enough. Watering can sometimes cause trees to outgrow the canker (make sure you have adequate drainage, as Leland’s are susceptible to Phytophthora root rot). It’s better to thin the stand and spend a little more on watering than to loose the entire screen and have to replace it.
Hemlocks: Like the American chestnut, American elm and butternut, we are seeing another species disappear before our very eyes. We have already lost millions of hemlock from Nova Scotia to Alabama. Infected trees will eventually die unless treated for hemlock whoolly adelgid. Many hemlocks are attacked by spider mites after being treated for HWA (which in turn, will require treatment).
Various Species: Stressed white pines in the Piedmont will continue to yellow, bleed and die due to white pine root disease. Virginia pines will continue to thin, lean and fall due to Littleleaf disease. Yellow pines will continue to develop pitch cankers. We will continue to see poorly-planted maples develop Phytophthora basal canker. Oaks will continue to experience a host of secondary pests, such as boring beetles, leaf worms, bacterial leaf scorch and slime flux. A cool damp spring may bring anthracnose, while an Indian summer may bring fall webworm. Our native black cherries will continue to be attacked by tent caterpillars while poorly-planted flowering cherries will struggle with borers and butt rot. Yellow-bellied sapsuckers will continue to make small, horizontal holes on sugar maples and Bradford pears (looks worse than what it is). Ambrosia beetles and hypoxylon canker will continue to take out the weak.
Future Concerns: If it’s raining twigs under your pecans and hickories, you may have twig pruners. At any time we could see another outbreak of the southern pine beetle. The common oak moth has been found in Anderson. Oak wilt has taken a foothold in the Columbia area. Sudden Oak Death has been found in South Carolina, North Carolina and Georgia. Dogwood anthracnose, thousand cankers disease, Asian longhorned beetle, gypsy moth and emerald ash borer has not made it this far south…yet. All in all, it could be much worse. Enjoy your trees and the great Upstate
~ Randy Cyr (March 21, 2012).
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