LSU AgCenter agent Ricky Kilpatrick points out how to prune a branch properly during a presentation at the Bossier Parish Library in Benton Feb. 23. (Photo by Mary Ann Van Osdell. Click on photo for downloadable image.)

BENTON, La. – The No. 1 yard tree problem is damage caused by construction of new houses, according to Ricky Kilpatrick, LSU AgCenter agent in Bossier Parish.

Kilpatrick presented his annual “Top Ten Yard Tree Problems” at the Bossier Parish Library in Benton Feb. 23.

Kilpatrick bases his list on phone calls and actual observances of local problems. He has been keeping the list since 1999.

Kilpatrick said soil movement, compaction, mechanical injury and other damage resulting from home construction are the culprits in the decline and death of yard trees.

“If you are building a house, leave more trees out there than you really want,” he said.

No. 2 is bacterial leaf scorch. Kilpatrick said he has confirmed cases in live oaks, water oaks, post oaks and southern red oaks.

Bacterial cells cause the problem by constricting the flow of sap through xylem. “If I had this, I’d prune that limb out and fertilize the tree,” he said.

The third problem is graft compatibility.

Kilpatrick said Bradford pear trees have been declining in the Shreveport-Bossier area. Many trees were turning to their fall colors in midsummer and then shedding their leaves.

After closer inspection, Kilpatrick said, many of these trees were found to have been grafted, and it appears that the root stock is growing slower than the scion or top material.

Bad pruning is fourth on Kilpatrick’s list.

After bad ice storms, homeowners want to prune back the large trees to reduce the chances of limbs falling through the house, he said. However, improper pruning will result in limbs weaker than the ones that were pruned.

Keys to good pruning are keeping your tools sharp, Kilpatrick said, adding that one-hand pruning shears with curved blades work best on young trees. He suggested not pruning for the first year of a tree’s life.

When you prune back to the trunk or a larger limb, branches too small to have formed a collar (a swollen area at the base) should be cut close, Kilpatrick said. Otherwise, follow the rules of good pruning on larger limbs by cutting at the branch ridge and collar and at a slight down-and-outward angle so as not to injure the collar.

Yard care ranks fifth in Kilpatrick’s list of tree problems.

Often homeowners with good intentions cause problems for their trees while tending their lawns, Kilpatrick said. One of the worst problems is improper use of lawn chemicals.

Another common problem is lawn mower and weed trimmer damage. Trunk and root injuries not only stress and weaken trees but create entry points for insects and diseases, Kilpatrick said.

Sixth on his list is site selection. Studying the site and understanding soil characteristics are the beginning steps in planning for landscape trees. “It’s a good thing to know what your soil pH is,” Kilpatrick said.

Homeowners should take a soil sample and use the results to select the appropriate trees to plant, Kilpatrick said. The LSU AgCenter can evaluate soil for nutrients and minerals, along with the soil pH. More information is available at parish extension offices.

The next culprit is fire blight. “If you have pear trees, you’ll have fire blight,” Kilpatrick said. This is a bacterial disease.

Eighth are the eastern tent caterpillar and fall webworm, which construct webs on tree branches and detract from aesthetic values.

No. 9 is oak decline and root rot. Oak decline is often a result of a complex interaction of various environmental stresses and pests. Root rot is commonly found in these stressed trees.

Galls round out Kilpatrick’s list.

Galls are often a problem in hickory trees and more recently in oaks, he said. The trees are attacked by a group of small insects called gall makers that cause deformities known as galls. The galls are formed when the female insects lay their eggs on the leaves or twigs.

The reaction between chemicals deposited by the insect and the plant’s hormones result in the formation of the gall, Kilpatrick said.

Kilpatrick’s honorable mentions are oak leaf blister and wildlife damage.

Leaf blister is favored by mild, moist conditions during the early phases of leaf growth. Severe cases may cause heavy premature defoliation, Kilpatrick said.

Damage done by woodpeckers, sap suckers, deer, squirrels, rabbits, beavers, nutria and domestic farm animals can strip off bark.

Kilpatrick said the pine beetle has dropped off his Top Ten list.

Kilpatrick offered a number of practices to promote good tree health:

– Prune to reduce competition for moisture and nutrients and to favor the more vigorous section of the tree.

– Mulch to reduce competition from sod and to reduce or alleviate soil compaction.

– Fertilize to correct nutritional deficiencies.

– Use insecticides as needed to reduce defoliation.

– Water.

Mary Ann Van Osdell