Verticillium wilt is a typically fatal disease that affects a wide range of deciduous woody ornamentals in Wisconsin. Trees most commonly and severely affected are maple and ash, but barberry, catalpa, elm, lilac, linden, smoke-tree and redbud are also susceptible. Symptoms and management are covered in this factsheet.
The viburnum leaf beetle (VLB), Pyrrhalta viburni, is an invasive insect that feeds exclusively on and can significantly damage Viburnum species. Currently found in limited areas, mostly in southeastern Wisconsin, its spread is being monitored. Identification and control are described in this factsheet.
Author(s): Chris Williamson, P.J. Liesch, Jim Kerns, Roger Flashinski Woody Ornamentals Pest Management in Wisconsin is an indispensable resource for nursery growers. This completely revised publication identifies pests of trees and shrubs in the state plus the products available for their control. It also notes products that are registered for use by homeowners (56 pages; […]
Author(s): M.F. Heimann, G.L. Worf “Decline” is a general term that describes the deterioration of a tree’s crown or an overall reduction in vigor. “Dieback” indicates more localized symptoms, with healthy branches adjacent to dead or dying ones. Find out more about tree decline and dieback, how to spot the difference between the two, and […]
Author(s): M.F. Heimann, G.L. Worf Scorch, or the browning of leaf edges, affects a wide range of deciduous and evergreen plants throughout Wisconsin, especially ash, linden, maple, oak, pine, and spruce. While scorch is easily recognizable, it’s important to recognize that it is a symptom, not a cause. A number of problems cause symptoms that […]
Author(s): Jane Cummings Carlson, A. Jeff Martin, Kyoko Scanlon Thousands of oaks in woodland and urban settings die every year from oak wilt, a fungal disease that is widespread in Wisconsin, Minnesota, and Michigan. Both the red oak and white oak groups are susceptible, but trees in the red oak group fall prey to the […]
Author(s): C.F. Koval, D.L. Mahr, P.J. Pellitteri Cottony maple scale is an insect that can infest the twigs of maples and other shade trees with popcorn-sized cottony masses. These masses produce a considerable amount of sticky liquid that resembles tree sap and eventually turns black due to fungal growth. Infestations are usually more severe in […]
Author(s): M.F. Heimann, G.L. Worf Springtime weather injury can cause misleading symptoms on foliage. This fact sheet describes symptoms and steps to minimize the likelihood of injury (2 pages). Click on this link to view the PDF of this fact sheet.
Author(s): G.L. Worf., J.E. Kuntz Many problems and disorders can lead to tree decline. This fact sheet explores sun scald, girdling roots, mower injury, previous defoliation, graft incompatibility, twine and tree wrap injury, and gas leaks as common causes of tree decline and death (4 pages). Click on this link to view the PDF of […]
Author(s): R.C. Williamson, C.F. Koval Skeletonizing of the leaves of roses, raspberries, grapes, fruit trees, and many other cultivated trees and shrubs may be caused by the adult rose chafer, Macrodactylus subspinosus (Fabricius). Adult beetles are attracted to flower blossoms, particularly roses and peonies. Damage occurs in June and tends to be most severe in […]
Root-knot nematodes (Meloidogyne spp.) are small, soilborne, worm-like organisms that infect many agricultural and horticultural plants. This publication describes the symptoms, management and control of root-knot nematodes in Wisconsin.
Foliar nematodes are microscopic worm-like organisms in the genus Aphelenchoides. They live in and on the leaves (and other above-ground plants parts) of over 450 plant species in more than 75 plant families. They are commonly found on hostas, but can affect other herbaceous ornamentals. Learn what to look for and how to manage foliar nematodes in this factsheet.