Pesticide

Invasive plant management on roadsides workshops

Invasive plants have been shown to impact Wisconsin’s economy, environment and human health. Roadsides are a key area where these unwanted plants establish and spread. These right of way habitats are challenging to work in but focused efforts can be successful in preventing spread and reduce invasive plant populations.

To help educate and jumpstart management, The University of Wisconsin-Madison Extension along with 4-Control are conducting roadside invasive plant workshops throughout the state. We invite you to attend one of these five regional workshops. While this training is available to anyone interested, the focus will be on training staff of municipalities that manage vegetation on roadsides. Continue reading “Invasive plant management on roadsides workshops”

Treat your valuable ash trees against EAB

By Bill McNee, DNR forest health specialist, Oshkosh, bill.mcnee@wisconsin.gov, 920-360-0942

Spring is the best time to evaluate valuable ash trees and determine if they should be treated to protect them from emerald ash borer (EAB). Emerald ash borer is currently the most damaging threat to trees in the state, killing more than 99 percent of the ash trees it infests.

Insecticide treatments to prevent EAB infestation are usually applied between mid-April and mid-May, so it is important to start planning now. The first thing homeowners should do is check their ash trees for signs of infestation. Woodpecker damage is easy to see this time of year and is often the earliest visible sign of EAB. Photos of other signs and symptoms can be found on the DNR EAB website.

Ash trees with woodpecker "flecking" indicate EAB infestation.

Signs of EAB infestation include woodpecker damage where the birds pick away ash tree bark to feed on larvae.

Emerald ash borer has become so widespread that homeowners should consider treating valuable ash trees no matter where they are in Wisconsin. The highest risk of EAB infestation is within 15 miles of a known infestation, but it is widely believed that there are additional, undetected EAB infestations throughout the state. To see a map of known EAB infestations, visit the Wisconsin EAB website.

While the best time to treat ash trees is before they are infested, treatments of infested trees can still be successful if done while EAB populations within the tree are low or moderate. Some ash trees may be too heavily infested to save or they may have other problems that make them poor candidates for treatment.

Trunk injection treatment for EAB. Credit: Matthew Karst.

Trunk injection treatment to protect against EAB. Credit: Matthew Karst.

You should consider several factors when deciding whether to treat your ash trees. Insecticide treatments can be costly, but the investment may be worthwhile if you consider the many benefits that healthy yard trees provide, including higher property values, better air quality, shading and cooling for homes and more. Removing and replacing your ash trees is another option and may be the best choice for heavily infested and lower value trees. For trees that you decide are worth saving, however, the cost to treat may still be less than removing and replacing them with other species. This factsheet from UW-Extension can help you decide whether a tree is worth treating.

If you decide to treat, or if you want to discuss treatment options with a professional, call a certified arborist or search online and in phone books for other businesses. Check the credentials and insecticide applicator certification of any business before hiring them to treat your ash trees.

Treatments are not economically practical for ash found in woodlots. Any questions about woodlot management should be directed to a professional forester.

Despite the cold winter temperatures in late January and early February, don’t postpone treatment of ash trees. Weather data and collection of overwintering EAB larvae at two sites in Waukesha County predict high insect survival rates in most of the state. Female beetles can lay up to 200 eggs, so EAB populations will quickly rebound from any mortality that occurred due to cold weather.

More information about EAB and management options can be found through the Wisconsin EAB website.

Treat your ornamental ash trees for emerald ash borer this spring

A yellow ornamental ash tree at peak fall color. This tree is worth treating to protect it from being killed by emerald ash borer.

High-value ash tree at peak fall color.

March is a good month to consider insecticide treatments for high-value ornamental ash trees this spring. Emerald ash borer (EAB) has been found in 42 Wisconsin counties and is expected to be more than 99% fatal to ash trees that are not protected with insecticide every 1-2 years. Many insecticides used in EAB treatments are applied between mid-April and mid-May, and now is a good time to contact a tree service or other pesticide application business if arranging for professional insecticide treatments.

Property owners with susceptible ash trees should consider a number of factors when deciding to treat their ash trees, including financial cost, tree condition and location, the shade a tree provides, its contribution to property values, and aesthetic view. Homeowners should also consider the financial cost of removing a tree that is killed by EAB, and the benefits that a dead tree no longer provides.

Continue reading “Treat your ornamental ash trees for emerald ash borer this spring”

Pesticide applicator training (PAT) – newsletter

The University of Wisconsin Extension Pesticide Applicator Training (PAT) program produces a newsletter dealing with information relevant to pesticide rules, regulations, certification, testing and more. The newsletter is called PAT CHAT and it comes out quarterly.

If you would like receive notifications of when the Pat Chat Newsletter is available, send an email to join-patprogram@lists.wisc.edu.

Written by: Todd Lanigan, forest health specialist, Eau Claire, (Todd.Lanigan@wisconsin.gov), 715-839-1632.

Stump treatment to prevent heterobasidion root disease (Annosum)

Applying a preventative treatment to a fresh pine stump using a backpack sprayer.

Applying a preventative treatment to a fresh pine stump using a backpack sprayer. Photo by: Linda Williams, WI DNR.

There are currently two products available to treat fresh pine stumps to prevent new infections of heterobasidion root disease (HRD), which was previously called annosum. The products are Cellu-Treat and Rotstop-C. Both are water soluble and can be sprayed on the stump. Sporax, a granular/powder product, was previously available but is no longer being manufactured. If you still have a supply of Sporax you can continue to use it. The one-page factsheet on HRD (Annosum) has been updated with information on where to purchase the available products.

For more information on Cellu-Treat and Rotstop-C please check out these websites:

Written by: Kyoko Scanlon, forest pathologist, Fitchburg (Kyoko.Scanlon@Wisconsin.gov), 608-275-3275.

Transline® herbicide trial begins

In keeping with the Reforestation Program’s mission of providing pertinent information to forestry professionals, we began a new herbicide field trial with Transline® (clopyralid). Many foresters and landowners are interested in applying herbicides after a site has been planted to inhibit weed competition. However, in the case of Transline®, not all species are referenced on the label. In addition, the varying rates prescribed may impact species differently. All of this can create a challenge for a forester or landowner when managing competition within the planting. Continue reading “Transline® herbicide trial begins”

Herbicide testing in nursery environment

Over the course of several years of monitoring new plantings on landowner properties throughout the state, reforestation staff encountered a wide range of herbicide prescriptions, with varying results. Often, staff encountered trees showing a high degree of stress, or even mortality, which appeared to be linked to the herbicide application.  The decision was made to test some herbicide treatments in our nursery to see how stock reacted to the chemical at various rates and application timings, under more controlled conditions than what is typically found on outplanted stock.  We selected Dupont Oust XP (Sulfometuron Methyl) as our test chemical, since it is the most widely used pre-emergent herbicide currently in use in Wisconsin.

Continue reading “Herbicide testing in nursery environment”