COLLEGE STATION, Texas – Texas A&M Forest Service is offering cost shares for Texas landowners to suppress the spread of oak wilt through the Texas Oak Wilt Suppression Program.

Eligible oak wilt suppression practices through this program include trenching or removal of infected red oak trees. All treatments must be installed according to Texas Oak Wilt Suppression Program guidelines and approved by Texas A&M Forest Service personnel. An application for cost-share funding must be approved before any cost-shareable treatment can begin.

Funding for trenching is limited to 50% of approved costs up to $2,000 per cooperator year. Multiple cooperator project costs are limited to 50% of approved costs up to $6,000 per project year.

Funding for tree pushing within trenched areas is limited to 50% of approved costs up to $2,000 per cooperator per year.

Funding for removal of certain diseased red oaks is limited to 50% of approved costs with a maximum of $2,000 per cooperator year.

Oak wilt is one of the most destructive tree diseases in the United States and is killing oak trees in Central and West Texas at epidemic proportions. Oak wilt has been confirmed in 76 Texas counties. While destructive to the ecosystem, the effects of oak wilt can also reduce property value by 15 to 20 percent.

“Oak wilt fungus, Bretziella fagacearum, is responsible for the disease and spreads rapidly through the interconnected roots of live oaks” said Demian Gomez, Texas A&M Forest Service Regional Forest Health Coordinator. “All oak trees are susceptible to oak wilt, and red oaks are the most susceptible and can die within as little as one month of being infected.”

Oak wilt is spread primarily in two ways—above ground by sap-feeding beetles or below ground through interconnected root systems between trees.

Above ground, infected trees that died the year before may produce spore mats under the bark, creating a fruity smell which attracts sap-feeding beetles. As the beetles carry fungus spores on them, they easily infect other oak trees through any fresh wound on the tree.

Below ground, oak wilt can travel an average 75 feet per year through the interconnected root systems of oak trees, primarily in live oaks, and is responsible for the majority of spread and deaths in Central Texas.

Trenching is a common method to prevent the spread of oak wilt underground by creating trenches at least four feet deep using trenching machines, rock saws or ripper bars. Trenches should be placed a minimum of 100 feet beyond symptomatic trees.

Landowners unaffected by oak wilt should continue to take precautions to minimize the susceptibility of their oak trees to the disease.

“One of the easiest ways for oak wilt to spread is by fresh wounds in oak trees, so it is especially important to avoid pruning or creating new wounds on oak trees from February to June,” said Gomez.

Oak wilt is often recognized in live oaks by yellow and brown veins showing in leaves of infected trees, known as veinal necrosis. The signs of oak wilt can be seen on a majority of leaves when a tree is fully infected. Landowners should contact a certified arborist if they are unsure if their tree is infected.

Landowners with oak wilt-infected trees can explore cost-share resources here: https://texasoakwilt.org/getting-help/oak-wilt-cost-share

Springtime and recent rains seem to have brought about the horn fly on cattle in our area. The name be misleading as they congregate on cattle without horns. Introduced to the U.S. from Europe in the late 1800s, they were named “horn fly” because they clustered at the base of the horns on cattle. Cattlemen know the flies now congregate almost everywhere on the cow’s body. 

Horn flies are the same color as a house fly but much smaller – about 3/16 of an inch in length. They lay their eggs in a freshly dropped cow manure pad where they hatch in about 24 hours. The manure needs to be less than an hour old because the female fly must deposit eggs inside the manure before the surface hardens.

The eggs will then hatch into larvae (also known as maggots) and after four to five days will pupate for a week to 10 days and then eventually emerge from the pad. Within two-three hours after emerging, they can be feeding on cattle, where they can take 30-40 meals per day.

The females can mate within two days after emerging and lay several hundred eggs a day later and for several days afterward. The entire life cycle takes 12-14 days in the summer. Horn flies appear on the first warm days of spring and are active until the fall and cool weather. They prefer warm, humid days.

Horn flies are quite the irritant for cattle as they puncture the skin to suck blood and usually are found on parts of the cow’s body not easily reached by the head or tail. Horn fly bites can cause extensive hide damage.

When temperatures are high, they move to the shaded parts of the belly. Unlike most flies, they remain on the animal day and night. Large numbers of horn flies cause constant irritation and can cause weight loss, loss of condition, and lowered milk production.

They can also transmit several diseases including Stephanofilariasis, a condition caused by a small parasite. This parasite causes the cattle to scratch and scrape themselves until they bleed to relieve the pain. Damage is so severe that it causes the large scars on the navels of many commercial cows. 

There are many management practices and several products and subsequent methods of application to help control horn flies. Management practices include pasture rotation that helps break the life cycle and dragging small pastures and traps to break up manure pads.

There are biological control methods including mites, beetles and wasps that feed on the larvae as well as dung beetles, which help break up manure pads. Interestingly, the much-hated fire ant even helps to reduce the numbers of horn flies in the pasture as they consume the fly maggots. 

Apart from waiting for natural control, stockmen have several options they can purchase to protect their cattle. Direct pest control methods include a variety of chemicals that are either self-treatment or applied as sprays, pour-ons, dips, ear tags, dust, back rubs, insecticide balls and in dust bags. Insect growth regulators (IGRs) in mineral or other feeds inhibit the larvae’s development into adult flies. Each product and application have pluses and minuses, but a combination of management and chemical control yields the best results if not complete control. Many savvy cattlemen use a combination of approaches that may include pasture rotation, ear tags, as well as an IGR.

For more detailed information on the active ingredients and methods of control, there is an AgriLife Extension fact sheet entitled “Protecting Cattle from Horn Flies” written by Dr. Sonja Swigert, an Extension Veterinary Entomologist with the Texas A&M AgriLife Extension Service.  She has another publication that discusses other external parasites and their control. That one is called “Managing External Parasites of Cattle”. If you cannot find it online, feel free to contact your local AgriLife Extension office.