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…

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…

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…

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…

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…

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…

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…

“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…

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…

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…