Resources for landscapes and gardens in the Midwest
Landscape Report
Plant Diseases
Don’t miss the 2019 Purdue Turf and Landscape Field Day on July 9th! Your opportunity to interact with Purdue Specialists, see the latest on-going research and best management practices, and network with others in the Green Industry. This is the premiere Green Industry education event that you’ll find this summer! https://www.mrtf.org/event/turf-and-landscape-field-day/?event_date=2019-07-09 In the landscape track,[Read More…]
The Cooperative Extension Service is a national network of land-grant colleges, universities, and the United States Department of Agriculture serving communities across the country by providing research-based information and educational programming. Purdue Extension serves Indiana residents in the following program areas: Agriculture and Natural Resources, Health and Human Sciences, Community Development, and 4-H Youth Development.[Read More…]
Although most cities contain an Elm Street, very few cities can claim having mature American elms on that street, or any other. The American elm was a premier street tree: Tolerant of compacted soil, fast growing, long-lived, and with a beautiful vase-shaped form. It’s very popularity led to its downfall. The introduction of Dutch elm[Read More…]
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…]
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…]
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…]
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…]
Hosta Virus X (HVX) is not a new problem, however, it’s not as prevalent as it was nearly a decade ago because growers have gotten better about recognizing the disease and removing infected plants from their nurseries. The most common symptoms include mottled, light or dark green discolorations along leaf veins (Fig 1). HVX may[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…]
Hakone grass (Hakonechloa macra), also known as Japanese forest grass, is often used for massing in beds in where a low maintenance ground cover is needed in semi-shaded areas. The graceful arching stems along with the availability of gold or white striped variegated cultivars make it an attractive option. There are few reports of disease[Read More…]
Volutella stem and leaf blight, caused by the fungal pathogen Coccinonectria pachysandricola (=Volutella pachysandricola), can cause major damage to Pachysandra – destroying large areas in a bed. (Fig 1) Infected leaves first develop tan or brown blotches with dark brown margins, which expand, often with concentric lighter and darker target-like zones. (Figs 2a,b) Stem and[Read More…]
Fungal diseases of ornamentals will always be a limitation to profitable plant production and management—how significant that limitation is in your hands. Fungicides are effective in reducing the risk of loss– in numbers, in quality and in terms of aesthetics. However, fungicide costs in terms of product cost, number of applications and labor need to[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…]
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…]
Bacterial leaf scorch (BLS) on oak is a systemic disease caused by the bacterium Xylella fastidiosa (Xf) (Fig 1). The bacteria live in the xylem vessels (water conducting elements) and restrict water flow. Xf is transmitted from tree to tree by xylem-feeding insects such as leafhoppers and treehoppers. Numerous woody hosts are susceptible to various[Read More…]
Tubakia leaf spot, a fungal disease, infects all species of oak. However, oaks in the red oak group such as black, red and pin oak, appear to be most susceptible. Symptoms on oak include small to large dark brown or reddish-brown spots or blotches. (Figs 1,2,3) Spotting that occurs on leaf veins may cause large[Read More…]
Boxwoods losing leaves should not be ignored!! Check them carefully for tell-tale symptoms of boxwood blight, a serious fungal disease that causes rapid defoliation and dieback (Fig. 1). The fungus that causes boxwood blight can infect all above ground portions of the shrub. The first symptoms of the disease are dark leaf spots (Fig. 2[Read More…]
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