The emerald ash borer (EAB) is an invasive, wood-boring beetle. It was first discovered in the United States in southeastern Michigan in 2002. Experts believe the pest entered the country on solid wood packing material originating from Asia. Since its discovery, the emerald ash borer has killed millions of ash trees in North America. EAB was first confirmed in Texas on May 6, 2016, in Harrison County. It has since spread across the state, with confirmed infestations in Dallas and Denton counties. As of 2024, EAB has moved south and was recently confirmed in 5 new Texas counties. **If you have an ash tree on your property, you MUST treat for emerald ash borer every 2 years.** Otherwise, the tree should be removed and replaced with a regionally appropriate species. ## What does EAB do to ash trees? The larval stage of the borer feeds on the inner bark of ash trees, preventing the tree from transporting nutrients and water. Larvae actively feed from the early summer through the fall. Infested ash trees become stressed and decline quickly—most die within 2–3 years of initial infestation. Ash trees killed by EAB are brittle and structurally compromised, making them much more susceptible to damage caused by high winds and storms. Additionally, they are extremely dangerous to remove through conventional methods and may require costly crane removal. ## Signs and Symptoms of EAB - **Canopy dieback:** Begins in the top third of the canopy, continues until the infested tree is bare. - **Epicormic shoots:** New shoot growth proceeding from the bark of infested trees, usually found in the roots or on the trunk. The leaves from these shoots may be larger than usual. - **Bark splitting**: Vertical ruptures in the outer bark, often exposing larval feeding galleries underneath; splitting caused by host tree forming woundwood in response to larval feeding activity. - **D-shaped exit wounds:** Caused by adult beetles emerging from the bark of infested ash trees. - **Serpentine larval feeding galleries**: Found in the inner bark of infested ash trees. - **Increased woodpecker activity and damage:** Due to woodpeckers feeding on EAB larvae. ## How is EAB transmitted? Emerald ash borer, like other wood pests, may be spread when infested ash trees, logs, or firewood are moved from a quarantine zone. This may spread EAB to different regions or even between states. When the mature beetles emerge from the ash tree in June, they spread within the infested region by laying eggs inside nearby ash trees. Adult emerald ash beetles can fly at least 1/2 mile from their home tree. ## Treating EAB The most effective treatment for EAB is preventative. Treatment involves applying an insecticide to the ash tree via trunk injection. The best time to treat for EAB is in the spring while the larvae are still young and unestablished. If EAB has been detected by the presence of symptoms, the infested tree has most likely sustained significant damage. At that point, it may not be feasible to treat the infestation. Instead, the infested ash tree should be removed and destroyed in accordance with state and federal guidelines.

Oak wilt is a fungal disease affecting oak trees. The fungus grows and spreads throughout the tree’s vascular system, depriving the host of nutrients and water. The presence of the pathogen triggers an immune response from the host tree which further blocks the movement of water. These two symptoms effectively choke the oak tree until it begins to wilt and die. ## How is Oak Wilt Transmitted? The fungus responsible for oak wilt—*Bretziella fagacearum*—is primarily spread in two ways. First, oak wilt may be transmitted over long distances by sap-feeding beetles, commonly known as picnic beetles. These beetles feed on the spore mats of diseased oak trees. The beetles then carry the spores with them to feed on the sap from a fresh tree wound, such as a pruning cut. Second, oak wilt may be transmitted by root grafting. When two trees of the same species grow in close proximity to one another, their roots will graft together and fuse, much like a skin graft. If either tree is infected, the pathogen may spread to the other. This is why oak wilt is a problem if it is present in your neighborhood. ## Preventing Oak Wilt The most important step to prevent oak wilt is to avoid wounding your oak tree when conditions are favorable for transmission. According to the Texas Forest Service, you should avoid pruning oak trees from February 1 to June 30. If it is necessary to prune or otherwise wound an oak tree in that time, a pruning sealer should immediately be applied to the wound. If oak wilt has been identified in your neighborhood, preventative oak wilt injections may protect your oak trees from the disease. The fungicide spreads throughout the vascular system of the tree, preventing the pathogen from taking root. The Texas Forest Service recommends injecting high-value oak trees that are within 75–100 ft. of a symptomatic host tree. Susceptibility to the disease varies by species. While white oaks are generally resistant to oak wilt, red oaks are very susceptible to the disease and may die within months or even weeks of infection. Live oaks lie somewhere in the middle: some die within a few months, others die in 1–2 years, and a few (about 1/10) are infected but never succumb to the disease. ## Treating Oak Wilt If your oak tree becomes infected, it is possible to perform therapeutic injections. This involves injecting the symptomatic tree with fungicide to slow and hopefully stop the development of oak wilt in that tree. The best results are achieved if no more than 30% of the canopy is showing symptoms of oak wilt. If more than 30% of the canopy is symptomatic, it is unlikely that therapeutic injections will be effective.

Just like us, trees can suffer lasting damage from exposure to the sun and intense heat. Sunburn affects leaves, with discoloration and damage showing after sudden or intense exposure. Sunscald is a sun-induced injury to the bark—usually on the south or southwest side of young, thin-barked trunks. Species often afflicted include: maples (Japanese, red, and hybrids), ash, honeylocust, sweetgum, red oaks, pecans, elms, hollies, and magnolias. Both sunburn and sunscald are caused by exposure to intense light and heat. Changes in the landscape, such as limb loss or tree removals, can abruptly increase sun on parts of a tree that were previously shaded. The heat may be further intensified and reflected by nearby walls or pavement. Exposed to extreme heat and lacking insulation, the bark of young or thin-barked trees may die and later slough off. ## Symptoms of Sunburn & Sunscald *Foliage (sunburn):* Affected leaves first look washed-out or bleached, then redden. Overlapping leaves can make distinct “shadow” patterns. The sunburn may looking patchy in the canopy due to the changing light conditions throughout the day. Foliar sunburn frequently follows the path of the sun. For the same reason, sunburn is found most often in the south or southwest side of the landscape. *Bark (sunscald):* The early signs of sunscald are subtle: discolored bark and small vertical cracks. Bleeding may appear in the spring. Later, long vertical fissures form as dead bark peels away. Large wounds weaken the trunk and can contribute to future failure. ## Prevention The best way to prevent long-term sun damage to your trees is to improve the environmental conditions and cultural practices of your landscape. These measures are intended to reduce stress and avoid aggravating injuries. - Leave adequate lower branches on newly planted trees for a few years to shade the trunk. - Limit drastic canopy thinning. - Where possible, provide shade from the south/west with nearby plantings or a light-colored board/fence. - Reduce reflected heat from hardscape. - Keep trees evenly watered during prolonged heat/drought - Maintain a 2–4 in. organic mulch ring (not piled on the trunk). ## Management ### Sunscald (on the trunk) Sunscald may be managed with trunk wraps. Use **light-colored** wraps, such as kraft paper or breathable white fabric. **Do not** use dark materials; they intensify heating. Wrap without constricting the trunk, especially where it flares out near the base. Leave shading materials in place until the bark thickens or the canopy shades the trunk. Some practitioners use diluted white latex paint on lower trunks to reflect sunlight. We don’t recommend this as it can be difficult to make sure your paint is plant-safe. If damage has already occurred, watch the afflicted area over time—large, long fissures indicate structural weakness and may justify risk assessment or support. ### Sunburn (on the leaves) Proper irrigation and mulching can help the tree cope with extreme heat. Avoid fertilizing in hot periods, as this will stimulate tender growth which is ill-equipped to contend with extreme heat. For high-value plants, short-term shade cloth can limit sunburn during extreme heat, although it is visually obtrusive.