The DNR Division of Entomology & Plant Pathology has discovered that a shipment of boxwood plants infected with boxwood blight was shipped to Indiana in May. This is important because boxwood blight (Calonectria pseudonaviculata) is a fungal disease that infests members of the popular Buxaceae family, and is often transported through the nursery trade. Hosts…Read more about Boxwood blight found in Indiana[Read More]
Tom Creswell
Oak wilt has been found in most counties in Indiana and is one of the most serious threats to the health of oak trees in the Midwest, especially those in the red oak / black oak group. The disease is caused by the fungus Ceratocystis fagacearum and is spread from tree to tree by sap…Read more about Oak Wilt in Indiana[Read More]
Getting calls from panicked customers about black spots on maple leaves? You’re probably not alone, because now is the time when people start to notice maple tar spot. Every summer we get questions about black spots on maple leaves that look like tar. These spots are not actually “tar” on maple, but are rather a…Read more about Tar Spot on Maple[Read More]
Arborvitae varieties (Thuja spp.) provide some of our most beautiful and versatile evergreens for landscapes, with an extensive selection of sizes and types. Unless they get proper care, they also give us some frustrating failures. Here is my list of the most frequently encountered ‘Arborvitae Aggravations’, based on the samples and questions we get in…Read more about Top Arborvitae Aggravations[Read More]
The recent jump from Winter to Summer (with 2-3 days of Spring somewhere in there) got folks out looking at Tulips in full bloom now in northern Indiana. The only thing marring the view in one local planting was an outbreak of tulip fire, caused by the fungus Botrytis tulipae. The disease first shows up…Read more about Tulip Fire[Read More]
A group of samples of several varieties of blue holly (Ilex x meservae) arrived in the lab from a commercial nursery in late January with a common problem, yellowing and rapidly dropping leaves and general poor growth (Fig. 1). After ruling out disease and insects on the foliage we next checked the root systems. After…Read more about PPDL Case Study #2: Sickly blue holly[Read More]
Purdue’s Plant and Pest Diagnostic Lab (PPDL) receives more than 2000 samples for diagnosis each year. We’ll highlight some of the more interesting cases in the Purdue Landscape Report in brief case studies like this. PPDL Case Study #1: White Fungi on Crabapple Branch Earlier this year a landscaper submitted several photos of a crabapple…Read more about PPDL Case Study #1: White Fungi on Crabapple Branch[Read More]
