LSU AgCenter agent lists top 10 tree troubles

Ricky Kilpatrick, Van Osdell, Mary Ann  |  7/2/2008 1:01:21 AM

News Release Distributed 07/02/08

The No. 1 yard tree problem in Shreveport-Bossier is construction damage, according to Ricky Kilpatrick, LSU AgCenter area forestry agent.

Kilpatrick presented his annual top 10 tree troubles for Shreveport-Bossier at the monthly Lunch and Ag Discovery session at the LSU AgCenter’s Red River Research Station June 27.

Kilpatrick bases his list on observations of local problems and presents it David Letterman-style. He has been keeping the list since 1999.

By construction damage, Kilpatrick means neighborhood development in which a lot of soil is moved, killing the trees.

“Many times soil movement, compaction, mechanical injury and other damage resulting from construction are the culprits in the decline and death of yard trees,” he said.

Many trees, especially oaks, have shallow root systems, and adding, removing or compacting the soil on the roots is detrimental.

No. 2 is graft compatibility. Recently, Bradford pear trees have been declining in Shreveport-Bossier. Many trees were turning to fall colors in mid summer and then shedding their leaves. On close inspection, many of these trees had been grafted, and it appears the root stock is growing more slowly than the scion or top material, Kilpatrick said.

The forestry agent lists bad pruning as third in his top 10 list.

After ice storms, homeowners want to prune back large trees to reduce the chances of limbs falling through the house, Kilpatrick said. But improper pruning results in limbs weaker than those that are pruned out.

“Pampering the yard to death” ranks fourth.

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

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

Fifth on the list is hardwood scolytids – wood-boring insects that may cause dead and dying leaves on the outer tips of branches.

“They have been common in magnolias, dogwoods and maples recently,” Kilpatrick said.

The next culprit is the Eastern tent caterpillar, which builds its web in the crotch of a branch.

“If you have pear trees, you’ll have fire blight,” Kilpatrick said, calling this bacterial disease No. 7 on his list.

No. 8 is species/site selection – or planting the wrong type of tree for the soil structure, the forester said. Studying the site and understanding soil characteristics is the beginning step in planning for landscape trees.

“One good hint is to look at what is growing naturally nearby,” Kilpatrick said.

Homeowners should take a soil sample and use the results to select the appropriate trees to plant. “Every parish has soils maps,” Kilpatrick said.

The LSU AgCenter can evaluate soil for nutrients and minerals, along with pH, and provide customized recommendations for whatever crop or plant is to be grown. More information is available at LSU AgCenter parish offices or on the Internet at www.lsuagcenter.com.

Oak decline/root rot is ninth on Kilpatrick’s list.

Oak decline often is a result of a complex interaction of various environmental stresses and pests, he said, while root rot commonly is found in these stressed trees.

Homeowners can promote good tree health by pruning to reduce competition for moisture and nutrients and to favor the more vigorous section of the tree, Kilpatrick said. Other practices include mulching to reduce competition from sod and to reduce or alleviate soil compaction, fertilizing to correct nutritional deficiencies, using insecticides as needed to reduce defoliation and watering.

Tenth on Kilpatrick’s list of problems are galls, which often are a problem in hickory trees and more recently in oaks.

The trees are attacked by a group of small insects called gall makers that cause deformities known as galls, Kilpatrick said. The galls form 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 results in the formation of the gall, he said.

Receiving “honorable mentions” on Kilpatrick’s problem list were oak anthracnose, oak leaf blister and giant bark aphids.

Anthracnose symptoms include rapidly developing blight of leaves and shoots, characterized by browning and shriveling of young leaves, Kilpatrick said.

Leaf blister favors mild, moist conditions during the early phases of leaf growth. It is more prevalent in the southeastern Gulf States. Severe cases may cause heavy premature defoliation, but tree deaths caused by leaf blister haven’t been reported in this area, Kilpatrick said.

Bark aphids cluster on small twigs of oaks and other hardwoods where they pierce the stems and feed on the sap.

For more information on home lawn and grounds care, call your parish LSU AgCenter office or visit online at www.lsuagcenter.com.

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Contact: Ricky Kilpatrick at (318) 965-2326, or rkilpatrick@agcenter.lsu.edu  

Writer: Mary Ann Van Osdell at (318) 741-7430, ext. 1104, or mvanosdell@agcenter.lsu.edu

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