Like anthracnose diseases of other shade trees, sycamore anthracnose is a very common occurrence in the landscape (Figure 1). Symptoms of sycamore anthracnose normally develop as small spots or dead areas centered along the veins of leaves or along leaf margins (Figure 2). Under conducive conditions these spots expand, killing more leaf tissue and causing…Read more about Sycamore Anthracnose – Don’t let the rains get you down[Read More]
Trees, Shrubs, Vines
Introduction The Colorado Blue spruce is not native to Indiana and tends to be susceptible to disease. One common disease, caused by the fungus Rizosphaera kalkhoffii, results in the defoliation of the tree. If left untreated needlecast can lead to the death of the tree. Symptoms and Signs Symptoms of needlecast don’t develop until two…Read more about Needlecast in Colorado Blue Spruce[Read More]
Sudden oak death, as the name suggests, is a disease that is capable of rapidly killing certain species of oaks. It was first identified in California, in 1995. Two years earlier it was identified in Germany and the Netherlands, killing rhododendron. Because the pathogen originally infected and killed tanoaks, an undesirable, understory scrub tree, it…Read more about **SPECIAL ALERT** Sudden Oak Death[Read More]
Although most people are understandably concerned about boxwood blight, boxwood does suffer from a number of diseases, including Volutella blight and Macrophoma leaf spot. Unfortunately, boxwood also suffers from a stem decline, caused by Colletotrichum theobromicola. The following was written by Dr. Raj Singh, LSU. Boxwood Stem Decline by Dr. Raj Singh Available on line…Read more about Other Boxwood Issues[Read More]
A question that I often receive goes something like…. ‘How do I control grassy weeds in liriope and iris?’ At first glance, it would appear that those ornamental plants are very similar to grasses, but looks may be deceiving as they are actually not grasses. We know that broadleaf weeds can be controlled in grasses…Read more about Killing Grasses in ‘Grasses’? How to control grasses in non-grassy ornamental plants[Read More]
Oak leaf blister is caused by the fungus Taphrina caerulescens. Infections occur as buds swell and open during wet, spring conditions. Leaf blister symptoms usually appear within several weeks following infection as 1/4-1/2 inch circular, light green bulges on the top surface of leaves.(Fig 1) From the underside, the affected areas are sunken or depressed. These…Read more about Oak Leaf Blister – No Cause for Concern[Read More]
Q: I’ve attached pictures of the only tree we have on our property. Because it is our only tree, I am deeply concerned with the possibilities of irreparable damage to it. As you can see, one of the branches broke off during a November windstorm. Unfortunately, that left a bare gap on the trunk. Please…Read more about Ornamental Pear Fallout[Read More]
We all know that plants take up nitrogen in significant quantities, compared to some of the other essential nutrients. What most don’t know is that elemental nitrogen (N) is not what is taken up by plants. In fact, nitrogen can be taken up in only two forms, ammonium (NH4) and nitrate (NO3). Fertilizer labels will…Read more about Changing pH and Fertilizing at the Same Time? How nitrogen sources can change soil pH[Read More]
The Invasive Terrestrial Plant Rule was signed by Governor Holcomb and published on March 18, 2019. The rule goes into effect 30 days after publishing, so it will be effective later in April. The rule states with respect to the 44 plant species included on the rule: “a person must not: (1) Sell, offer or…Read more about Terrestrial Invasive Species Rule Signed by Indiana Governor[Read More]
It is easy to confuse Hemlock (Tsuga spp.) and Yew (Taxus spp.) unless you can see the overall plant habit or have them both side by side. Further confusing them is that both species may be pruned into hedges or other shapes that obscure the natural plant habits. Hemlock has short needles, 1/4 – 3/4″…Read more about Distinguishing Hemlock from Yew[Read More]
Sitting in your back yard on a warm day under the shade of a tree is one of the joys of spring, but there are a growing number of threats that could destroy this experience. Invasive species present dangers like those from above in the form of fragile dead ash trees and from below in…Read more about Emerald Ash Borer University Announcement[Read More]
A look back at the past year may help us be alert to problems ahead. Here’s a summary of the most common problems received in the diagnostic lab on woody ornamentals in 2018. As is typical for most years there were more non-disease (abiotic) problems than infectious (biotic) diseases found on PPDL lab samples in…Read more about Woody Ornamentals Summary 2018[Read More]
The time is now to start protecting your trees! Now that your ears are perked up, let’s talk a bit about Southwest injury on trees. Bark cracking (Fig.1) is a phenomenon that occurs in many species of trees and can have many causes. One of the most common types of bark cracking is termed Southwest…Read more about Preparations to Prevent Southwest Injury[Read More]
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]
Burning bush is so named for its brilliant red foliage display in autumn. But we sometimes get questions asking why their shrub fails to color up, with leaves that remain green until they drop from the plant. Fall color or lack thereof is affected by a number of factors, including genetics of the plant and…Read more about Alternatives to Burning Bush for Fall Color[Read More]
