Common Borers of Missouri

Show Me Smart Gardening Best Management Practices:

Tree Care: Avoid Wood Borer Issues!

Most common borers of Missouri:

Flatheaded appletree borer
Roundheaded appletree borer
Shothole borer
Peachtree borer
Lesser peachtree borer
Dogwood borer

For more information on these borers click here

(For specific on Missouri and Emerald Ash Borer click here )

Show Me Smart Gardening Best Managment Practice Guidelines

Wood borers are attracted to stressed trees. The stress can be caused a variety of reasons including transplant shock, injury, (common causes: mechanical: pruning, machinery and animal damage or environmental including ice storm, wind damage and other weather induced injury from freeze and thaw cycles. Also drought, compacted soil and limited/ confined root room (competition from other trees, construction and hardscape such as pavement.)

Most of the time healthy trees can fend off wood borer attacks and are able to recover from a limited number of borer attacks.

BMP recommendations:

Avoid damaging tree trunks and roots with mowing equipment and string weed trimmers.
Avoid pruning oaks in spring and summer, when beetles carrying the oak wilt fungus and wood borer adults are active.
Do not have trees topped (cutting branches back to stubs in a hat-rack manner.) Topping stresses trees, increasing their risk of tree decline and death.
Place mulch around the base of trees to conserve moisture. Mulch should be distributed 2 to 3 inches deep in a ring around the tree, but should not touch the trunk or be piled against it in a volcano shape.
Provide supplemental water during summer droughts by allowing a hose to drip slowly on the soil above the root zone at approximately two-week intervals.
Wood borers are difficult to control with insecticides, and few insecticides are registered for treating wood borers in landscape trees. Attempts to use insecticides are likely to be ineffective and may have harmful effects for humans or the environment.

Betula nigra river birch selection still being recognized

River birch's 'Heritage' cultivar was selected by the Society of Municipal Arborists as 2002 Tree of the Year. Since then it has been featured, promoted and recommended throught Missouri and Illinois as an outstanding choice for cultivated green spaces.
'Heritage' birch is a selection of one of Missouri's most popular and common native trees Betula nigra . 'Heritage' was found and propagated by Earl Cully from a tree growing naturally in Illinois that displayed outstanding bark color and classic form. It has wonderful ornamental value appropriate for commercial and residential use in the lower Midwest. Resistant to birch borer, it tolerates turf competition, lawn irrigation, and poor drainage.
It is a large hardy, fast-growing, nicely forked tree, so allow adequate room to enjoy its beautiful spreading natural habit. Because the birch wood is somewhat naturally pliable, it tends to be wind and ice resistant except in the most extreme conditions.

River birch is very attractive and worthy of specimen placement and uplighting opportunities. The many layers of bark peels in colorful flakes of cinnamon brown, salmon, peach, orange, and lavender and is a bonus in regions where paper and white birches are plagued by borers. It is especially notable during the dull gray days of winter!

For more tidbit information about Earl Cully's 'Heritage' Birch and its history click here

Prune Pin Oaks Now To Avoid Oak Wilt

Avoid pruning oak trees from April to October. Remember this rhyme,

DON'T PRUNE

IN APRIL, MAY

AND JUNE!

Oak Wilt
By Dennis Patton
DPatton@oznet.ksu.eduCounty Extension Agent, Horticulture Johnson County, KansasKansas State University Research and Extension
Oak wilt can attack all species of oak, but the red oak group is most susceptible. This group includes red oak, blackjack oak, and pin oak. The white oak group is more resistant to the oak wilt fungus, which is usually found in oak woodlots or in urban subdivisions that were built in areas where native oak stands were present.
From mid-May to early June, oak wilt symptoms become apparent. Infected trees show a bronzing or wilting of leaves on individual branches or on a portion of the tree crown. The leaves appear scorched on the outer half of the leaf, which then turns red or brown, and the inner half of the leaf, nearest the leaf stalk, remains green. In a few weeks, wilted leaves start to drop. Wilting spreads to other portions of the tree during the summer. Most red oaks are killed in one season.
If you suspect oak wilt, collect a sample of a wilting branch that is at least one-half inch in diameter and six inches long. Make sure the sample is not exposed to high temperatures, as the fungus is very sensitive to heat. Take the sample to your County Extension Office. Because oak wilt can be confused with other problems on oak, a sample is needed to positively identify the presence of the wilt fungus.
Since the fungus can pass from one tree to another by root grafts, and since oak trees within 50 feet of each other often have a common root system, oak wilt can quickly spread through a stand of oaks. Thus, to avoid transmission of the disease, control methods must concentrate on inhibiting the root-to-root contact. Trench to a depth of 3 feet between adjacent healthy and diseased trees. Also, oak wilt may be spread by insects, birds and small mammals, so avoid pruning in late spring, as the sap seeping from wounds might attract insects that could spread the disease.
A tree infected with oak wilt cannot be saved. Remove it and destroy the wood. The only way you can possibly use the wood for firewood is to split and stack it, cover the whole pile with 4-mil clear plastic tarp that has been sealed to the ground. There should be no tears or holes in the plastic, and the pile should be tarped all summer. Since the fungus is sensitive to high temperatures, this treatment will heat the wood sufficiently to destroy the oak wilt fungus.
Fungicide injections should only be considered for healthy oaks adjacent to oak wilt pockets. For more information about oak wilt, call your County Extension Office.