Mitigating the Impacts of Invasive Species in Texas
February 24, 2025 – COLLEGE STATION, Texas – Invasive species cause many negative impacts to the Texas landscape, from the displacement of native trees to potentially killing entire species. Because of their widespread impact, Texas A&M Forest Service takes great lengths to help mitigate their impacts and is highlighting those efforts during National Invasive Species Awareness Week.
Invasive species have two main characteristics: they are non-native to an ecosystem and their introduction is likely to cause harm to the economy, environment or human health. Non-native species are those that do not naturally originate in the area or region where they are found.
“Human activity is often responsible for introducing non-native and invasive species into new ecosystems,” said Demian Gomez, Texas A&M Forest Service Regional Forest Health Coordinator. “This includes planting ornamental trees and plants or accidentally transporting insects in wood packaging material, firewood or other goods.”
Invasive species are dominant and grow well in non-native environments because they lack natural competitors, predators and diseases that normally regulate their populations in their natural environment.
Texas A&M Forest Service works to mitigate the spread and impacts of invasive species through proactive forest health management strategies. The agency also partners with other research organizations to track the spread of invasive pests, diseases and tree species.
Invasive species currently posing a significant risk to Texas include:
Emerald ash borer
Native to eastern Asia, the emerald ash borer (EAB) is a destructive, invasive wood-boring pest that has killed millions of ash trees in the U.S. and Texas. EAB was first detected in the U.S. in 2002 and was first reported in Texas in Harrison County in 2016. Since then, EAB has been detected in 27 Texas counties.
Adult EAB lay eggs in the bark of ash trees in the spring and early summer and the larvae burrow into the bark. The larvae feed on the phloem and cambium, disrupting the flow of nutrients within the tree leading to its death. EAB emerge from the tree as adults, leaving D-shaped holes in the bark.
EAB are easily spread long distances by human activity, especially by the transportation of firewood. They can also travel in unprocessed ash logs, ash nursery stock and other ash commodities.
Texas A&M Forest Service works with communities to develop, communicate and implement local EAB preparedness plans. And while the agency assists with planning, trapping and monitoring, the Texas Department of Agriculture is ultimately responsible for EAB management and coordination in Texas.
Saltcedar
Saltcedar trees are dominating wildlands and ranches, especially in the Texas panhandle, exacerbated by the loss of cottonwood and willow trees to wildfires. They were first introduced in the U.S. as an ornamental tree in the 1800s but escaped cultivation in the 1870s.
Saltcedars are aggressive invasive trees that can consume nearly 200 gallons in a day and their leaves and stems secrete high concentrations of salt into the ground around them. These factors diminish nutrients for native species. Additionally, saltcedars lack desirable protein for foraging wildlife.
Saltcedars are highly resistant to control, including mechanical management. The best removal method is spraying imazapyr or imazapyr in addition to glyphosate onto the tree.
Brazilian peppertree
Brazilian peppertree has invaded thousands of acres in coastal habitats since its introduction to Texas in the 1950s. This invasion has caused the shading and killing of native vegetation as well as allergic reactions in some people.
Since 2014, Texas A&M Forest Service has worked with the Texas Gulf Region Cooperative Weed Management Area in Port Aransas to address Brazilian peppertree in the region through eradication and education.
The agency has also been collaborating on a project led by the US Army Engineer Research and Development Center to reduce the impacts of Brazilian peppertree in the Texas Gulf Coast since 2023. The study aims to integrate tiny insects called thrips, referred to as a biocontrol, with ongoing mechanical and herbicide management of the Brazilian peppertree.
Researchers will release new insects and monitor the trees over two years to evaluate the impacts. The U.S. Forest Service provided funding for the project.
Laurel wilt and the red bay ambrosia beetle
Laurel wilt is a vascular fungal pathogen spread by the red ambrosia beetle. The pathogen was first reported in Texas in 2015 and has spread eastward, killing more than half a billion trees in the Lauraceae family. This loss has severely impacted redbays, sassafras and the avocado industry in the southeastern U.S.
This vascular fungal pathogen, transported and cultivated by the beetle to be used as a food source for larvae, can kill trees in less than a month.
Texas A&M Forest Service is working with public and private partners to study the spread and distribution of the disease/insect complex.
Silktree/Mimosa
Mimosa trees are widely used in landscaping due to their fragrant purple flowers and silky petals that bloom in the spring. This Asian native tree was introduced to Texas in 1745. Mimosas adapt to a wide variety of soils, and its seed coat is impermeable, allowing years-long dormancy.
Because of their large spanning canopy, mimosa trees can severely reduce sunlight and nutrients for native species.
Mimosa trees resprout with vigor when trimmed or wounded. Mimosas should be cut down to the stump, and then immediately thoroughly sprayed with herbicides to ensure the tree is killed down to the roots. Larger mimosa trees can be injected with Imazapyr or Triclopyr herbicides as a safer alternative to cutting the tree down.
Since invasive species are often introduced by human activity, Texas A&M Forest Service recommends mindful tree planting and activities. Moving firewood can be a culprit in transporting diseases, so it should be burned near where it is purchased or cut down.
Additionally, landowners can help prevent the spread of these invasive tree species and diseases by diversifying the native tree species on their land, creating a naturally competitive ecosystem. Learn more about planting the right tree in the right place: https://texastreeplanting.tamu.edu/.
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