In the last five years, we have received 233 samples from Indiana, alone, with concerns ranging from boxwood leafminer to Volutella dieback and cold damage (Figure 1, 2, 3). Often, we find multiple problems on any given sample, and very frequently we see Volutella in association with dark cankers of stems that appear to have…Read more about Boxwood Browning, Blights, and Cankers – 2023 Update[Read More]

All plants are susceptible to attack by pests and pathogens. Under certain conditions, a homeowner may require the use of a pesticide, but only after they’ve included, or exhausted the use of cultural practices like removal of diseased tissue (sanitation and eradication); considered resistant varieties to replace continual problem plants; and making sure the plant…Read more about Fungicides, Homeowners, and the Garden Center[Read More]

Creeping phlox (Phlox subulata) has been a reliable mainstay in home landscapes for generations. This spring-blooming perennial is also known by a string of other common names, including flowering moss, moss phlox, moss pink, rock phlox, and thrift (not to be confused with sea thrift which is Armeria maritma). Creeping phlox is native to a…Read more about Anthracnose on Creeping Phlox[Read More]

Periwinkle (Vinca minor) has a few disease issues that can cause severe damage to Vinca in cool wet weather, including Rhizoctonia stem and crown rot, Phytophthora root and crown rot, and Phoma stem blight. The last disease, Phoma stem blight, can cause severe damage to Vinca early in Spring when new stem growth emerges (Fig…Read more about Phoma stem blight of Vinca[Read More]

Each spring the PPDL receives several samples of oak trees showing curled, twisted, stunted and/or generally ratty looking leaves. When there are holes in the leaves or leaf edges are missing tissue, we add another symptom name to the mix: tatters. Distorted new growth and tatters are most common on white oaks and may occasionally…Read more about Oak Leaf Tatters – a spring ritual[Read More]

Pseudomonas syringae pv. syringae is an opportunistic bacterial pathogen that attacks a diversity of woody ornamental plants.  The bacteria cause flower blights, cankers, shoot blights, and diebacks. Symptoms Symptoms often begin as expanding leaf spots. On lilac and viburnum, small spots expand to irregularly shaped brown lesions with yellow halos (Fig. 1). For most other hosts…Read more about Pseudomonas syringae pv. syringae on lilac and other woody ornamentals.[Read More]

Rose rosette disease is a severe problem for rose growers and occurs widely throughout many rose growing regions of the US, especially from the mid-South into the Midwest. The problem was described on roses in the early 1940s but actual cause of the disease remained murky until the pathogen was identified as a virus in…Read more about Rose Rosette[Read More]

Why Scout? Pathogens, insects, weeds and other pests negatively impact ornamental plant production (greenhouse, nursery, landscape). Integrated pest management (IPM) strategies are used to prevent (ideally) or mitigate damage to ornamental crops. IPM strategies of ornamentals include practices such as proper plant choice for the site, incorporation of resistant varieties when available, the use of…Read more about Scouting 101[Read More]

Rust diseases produce some of the most dramatic symptoms and signs we see on woody plants in the landscape. These fungi live up to the name of ‘rust’ diseases because the spore structures they produce on the plant are generally bright orange, as shown by these examples:  Cedar-apple rust (https://purduelandscapereport.org//article/orange-koosh-galls-on-eastern-red-cedar/), Hollyhock rust (https://purduelandscapereport.org//article/jolly-hollyhock-rust/) and Buckthorn…Read more about Cedar Quince Rust[Read More]