Blog Archives

Dogwood Powdery Mildew

Dogwood is a popular landscape tree throughout Kentucky. However, once infected with powdery mildew, trees can develop an unattractive appearance. The disease is most prevalent during periods of high humidity and in landscapes with reduced air circulation. Some cultivars are

Posted in Landscape Trees & Shrubs

Spruce Dieback – Needle Cast Diseases May Be To Blame

Blue spruce and Norway spruce are popular landscape plants in Kentucky. However, many factors can cause spruce trees to cast (shed) needles. Casting may be the result of environmental stresses (heavy soil, poor drainage) or fungal diseases. In Kentucky, Rhizosphaera

Posted in Landscape Trees & Shrubs

Fall Webworms Getting Started Already

While the calendar says we haven’t even left spring yet (summer starts on June 20), we have already received our first fall webworm inquiry of the year. Even though their name implies that they would most enjoy the months of

Posted in Landscape Trees & Shrubs

Dieback in Landscape Trees – Could it be Verticillium Wilt?

The stress of hot, dry conditions in midsummer can prompt leaf scorch in many landscape trees. However, extensive canopy dieback or tree collapse, particularly on one side of a tree, may indicate Verticillium wilt disease.  Numerous cases of this vascular

Posted in Landscape Trees & Shrubs

Box Tree Moth- A Potential New Problem for Boxwoods

Boxwoods usually have to contend with insect issues like boxwood leafminer or boxwood psyllid. In recent years, we have had concerns arise over boxwood blight, also impacting Kentucky boxwood plants. Now, it seems like a new invasive is on the

Posted in Landscape Trees & Shrubs

Armillaria Root Rot – A Threat to Stressed Landscape Trees

Tree stress can come from numerous factors, including weather, mechanical damage, insects, or poor growing conditions. These stresses make plants more susceptible to the plant disease Armillaria root rot. This fungal disease is also known as shoestring root rot, mushroom

Posted in Landscape Trees & Shrubs

Hanging by a Thread

Dead, curled leaves dangling by fungal “threads” are typical of a disease called thread blight.  This disease is more common in eastern Kentucky, where it has been observed on apple, cherry, and viburnum.  Other potential hosts include cotoneaster, dogwood, gooseberry,

Posted in Fruit, Landscape Trees & Shrubs

Rhizosphaera Needle Cast May Lead to Skimpy Spruce

Rhizosphaera needle cast is often to blame for brown or thin spruce in the landscape. In Kentucky, Rhizosphaera needle cast is the most common disease of spruce; it also affects some pine species. This disease causes needle drop on lower

Posted in Landscape Trees & Shrubs

“Wet Feet” of Ornamentals

“Wet feet” is the common term for a condition that affects plant species intolerant of wet growing conditions. This problem occurs when soils become saturated in water, which ultimately causes roots to suffocate. Once root damage occurs, plants decline and

Posted in Landscape Trees & Shrubs

Laurel Wilt Disease: A Threat to Kentucky Sassafras Trees

Laurel wilt is a new disease that was recently detected in southwestern Kentucky. This disease, which is transmitted by the redbay ambrosia beetle, has the potential to rapidly kill sassafras trees. Currently no management options are available for this disease.

Posted in Forest Trees, Landscape Trees & Shrubs

Cherry Leaf Spot

Cherry leaf spot is a fungal disease of sweet, sour, and ornamental cherries. While this leaf disease is rarely a death sentence for trees, it can result in reduced blossoms, weakened trees, and increased risk for winter injury. Cherry Leaf

Posted in Fruit, Landscape Trees & Shrubs

Anthracnose Diseases on Shade Trees

The term anthracnose refers to the dark blotching (necrotic) symptom common to these diseases.  When expanding leaves are affected, leaf distortion frequently results (Figure 1). Defoliation (leaf drop) often occurs during severe infections. The disease is generally not fatal, and

Posted in Landscape Trees & Shrubs

Cedar-Hawthorn Rust

Cedar-hawthorn rust is a common disease of apple, crabapple, hawthorn, and ornamental pear in Kentucky; it also affects quince, mountain ash, pear, and serviceberry.  The pathogen overwinters as galls on its alternate hosts, cedar and juniper. Removal of these galls

Posted in Fruit, Landscape Trees & Shrubs

Volutella Blight of Boxwood

Volutella blight is the most common disease of boxwood in the landscape. Volutella blight is caused by an opportunistic fungal pathogen that attacks leaves and stems of damaged or stressed plants.  Winter injury, poor vigor, and wounds increase risk for

Posted in Landscape Trees & Shrubs

Dogwood Anthracnose Spotted

Anthracnose of dogwood is a common problem in Kentucky. Symptoms on landscape and forest dogwoods often first appear during wet periods in late spring. If left unmanaged, the pathogen spreads, eventually resulting in plant death.  Selection of resistant varieties and

Posted in Forest Trees, Landscape Trees & Shrubs