MAINTANING TREE HEALTH

Leininger, T.D; Solomon, J.D.; Wilson, A. Dan; Schiff, N.M. 1999. A Guide to Major Insects, Diseases, Air Pollution Injury, and Chemical Injury of Sycamore. Gen. Tech. Rep. SRS-28. Asheville, NC: USDA Forest Service, Southern Research Station. 44 p.

Because healthy trees are less susceptible to attack and injury by insects and diseases, sycamore plantings should be managed to optimize vigor. Seedlings and saplings that become stressed when planted “off site” or on marginal sites, and become further weakened by drought or other factors, are sometimes devastated by disease. The following cultural practices, singly or in combination, are suggested to promote and maintain good tree health in forest stands, plantations, nurseries, shelterbelts, and ornamental plantings:

1. Plant sycamore in deep, well-drained, loamy soils with a good supply of ground water such as alluvial soils, terrace soils, and fertile sites in coves and lower slopes. Site selection is the single most important factor in maintaining tree health and minimizing losses from diseases and insects.



2. Where possible, avoid planting sycamores on abandoned old-field sites with well-developed, impermeable hardpans, especially those that have been badly eroded and leached.



3. Use only vigorous planting stock (of adequate size and free of root and stem diseases) produced in nurseries that strictly follow recommended practices for growing, lifting, storing, and handling seedlings and cuttings.



4. When it is available, use planting stock from improved selections grown in sycamore seed orchards or from a locally adapted seed source. (Some research has shown that plants from seed sources north of a planting site are more severely damaged by certain canker diseases than those from seed sources south of the planting site.)



5. Ensure that trees receive sufficient water, nutrients, and sunlight through irrigation, fertilization, proper spacing, and other intermediate stand-management practices, such as timely thinning and crop-tree release cutting.



6. Use sanitation practices such as pruning, removing dead and symptomatic branches, and raking, discing under, or removing diseased and insect-infested leaves. Such practices reduce buildup of overwintering fungal inoculum and hibernating insects in plant debris that can cause new pest problems the following year.



7. Prevent or minimize injuries by harvesting and cultivation equipment, fire, or other sources that can create entry points for canker fungi, wood-decay fungi, and insect borers.



8. If pruning must be done, schedule it for the dormant season when fungi are inactive and less likely to colonize fresh wound sites. Always sterilize pruning tools with a solution of 50 percent laundry bleach and water before moving to the next tree.



9. Losses from canker diseases may be reduced substantially by early detection and shortened cutting cycles. However, when a shorter cutting cycle is not possible, cankered trees should be felled and destroyed or removed to minimize disease spread. Sanitation cuts of unmerchantable stands containing canker diseases are recommended when adjacent sites are to be planted in sycamore.



10. Managers should learn to identify serious diseases such as canker stain. Identification errors can result in premature and unneeded salvage harvest or failure to harvest trees that will die or become unmerchantable before the next cutting cycle.



11. Strictly follow label guidelines when using herbicides around ornamental plantings and shade trees as well as in nurseries and young plantations. Adequately shield young trees from direct contact or spray drift. When used improperly, herbicides can injure young sycamore trees.



12. Examine plantings regularly for disease symptoms and the first signs of insect feeding. Early detection will allow for the greatest number of pest-management options.



13. Insect pheromones and traps are available commercially for monitoring a number of species. Determining local, seasonal abundance can help establish the need for control and proper timing of insecticide application.



14. For information on pesticides or additional assistance with sycamore pests, contact your State Forester, county extension agent, or the nearest office of the USDA Forest Service, State and Private Forestry, Forest Health Protection.