Wisconsin White Mold Risk Map – July 15, 2016

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Sclero-cast: A Soybean White Mold Prediction Model

**This tool is for guidance only and should be used with other sources of information and professional advice when determining risk of white mold development. We encourage you to read the model how-to guide which can be downloaded by clicking here**

Risk of apothecial presence and subsequent white mold development has increased slightly in the south central portion of Wisconsin since the last posting on July 11 (see map below). Three-day forecasts show continued increase in the south and central portion of the state. While the risk may increase slightly, the risk is low to moderate. The UW Field Crops Pathology crew has been scouting for apothecia and has observed low numbers of apothecia in naturally infested, dry-land fields in Columbia Co. The prediction model forecasted this event earlier last week in this location. In irrigated fields around Hancock, larger numbers of apothecia have been observed. Risk in this portion of the state has been shown to be low (blue color), however, irrigation modifies this risk to a more moderate level. Growers who irrigate or are near moderate- or high-risk pockets should be considering their fungicide application options now.  The window of opportunity to apply fungicide to control white mold in soybean is between the R1 and R3 growth stages. Be sure to consult the how-to guide for assistance in interpreting this map if you are considering spraying fungicide to control white mold.

White Mold Risk - July 15, 2016

White Mold Risk – July 15, 2016

This model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold fungus apothecia. Weather information and maps are provided by the Soybean Integrated Pest Information Platform for Extension and Education (iPIPE), which is managed by ZedX, Inc. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, maximum relative humidity, and maximum wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, this map is generated and indicates areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. For further information on how to use and interpret this risk map, CLICK HERE to download a how-to guide.

Wisconsin White Mold Risk Map – July 11, 2016

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Sclero-cast: A Soybean White Mold Prediction Model

**This tool is for guidance only and should be used with other sources of information and professional advice when determining risk of white mold development. We encourage you to read the model how-to guide which can be downloaded by clicking here**

Risk of apothecial presence and subsequent white mold development has continued to decrease slightly for southern and south-central Wisconsin compared to the last model run (see map below). Three-day forecasts continue to show slight decreases in risk due to forecasted hot and dry weather for later this week. The UW Field Crops Pathology crew has been scouting for apothecia and setting traps for spores of the white mold fungus in fields in the soybean growing areas of south and central Wisconsin and HAVE NOT found any apothecia or captured spores. This confirms the generally low risk currently being predicted by the model. Growers near higher risk pockets should monitor the soybean crop for closing canopy and flowering growth stages that may lead to increased risk of white mold in these pockets. Be sure to consult the how-to guide for assistance in interpreting this map if you are considering spraying fungicide to control white mold.

White Mold Risk Map - July 11, 2016

White Mold Risk Map – July 11, 2016

This model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold fungus apothecia. Weather information and maps are provided by the Soybean Integrated Pest Information Platform for Extension and Education (iPIPE), which is managed by ZedX, Inc. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, maximum relative humidity, and maximum wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, this map is generated and indicates areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. For further information on how to use and interpret this risk map, CLICK HERE to download a how-to guide.

Wisconsin White Mold Risk Map – July 8, 2016

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Sclero-cast: A Soybean White Mold Prediction Model

**This tool is for guidance only and should be used with other sources of information and professional advice when determining risk of white mold development. We encourage you to read the model how-to guide which can be downloaded by clicking here**

Risk of apothecial presence and subsequent white mold development has decreased a bit for most of Wisconsin compared to the last model run (see map below). The UW Field Crops Pathology crew has been scouting for apothecia and setting traps for spores of the white mold fungus in fields in the soybean growing areas of south and central Wisconsin and HAVE NOT found any apothecia or spores. This confirms the generally low risk currently being predicted by the model. Growers near higher risk pockets in Dodge, Walworth, and Waukesha Counties should monitor the soybean crop for closing canopy and flowering growth stages that may lead to increased risk of white mold in these pockets. We have seen numerous fields this week in the R1-R2 growth stages. Be sure to consult the how-to guide for assistance in interpreting this map if you are considering spraying fungicide to control white mold.

White Mold Risk - July 8, 2016

White Mold Risk – July 8, 2016

 

This model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold apothecia. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, relative humidity, and wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, this map is generated and indicates areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. For further information on how to use and interpret this risk map, CLICK HERE to download a how-to guide.

2016 DATCP Soybean Phytophthora Survey Update

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Brown discoloration of a soybean stem as a result of infection by Phytophthora sojae. Photo Credit: Craig Grau.

Brown discoloration of a soybean stem as a result of infection by Phytophthora sojae. Photo Credit: Craig Grau.

Anette Phibbs, Plant Industry Laboratory Director, Wisconsin Department of Agriculture, Trade and Consumer Protection

Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

The Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) pest survey team collected soybean seedlings from 30 fields in eleven counties (Crawford, Dane, Fond Du Lac, Dodge, Grant, Green, LaFayette, Iowa, Jefferson, Racine and Rock Cos.) in Wisconsin in 2016. As of June 30, 11 of the 30 fields, or 36.6% have tested positive for Phytophthora sojae. The DATCP team is planning to collect 20 more samples including northern soybean growing areas in the state. Additionally, detection for other Phytophthora species will be performed once all samples are collected.

For information about Phytophthora root and stem rot caused by P. sojae, CLICK HERE to download a fact sheet. Additionally, you can visit the soybean disease page by CLICKING HERE and scrolling down to “Phytophthora root and stem rot.”

Wisconsin White Mold Risk Map – July 5, 2016

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Sclero-cast: A Soybean White Mold Prediction Model

**This tool is for guidance only and should be used with other sources of information and professional advice when determining risk of white mold development. We encourage you to read the model how-to guide which can be downloaded by clicking here**

Wisconsin White Mold Risk in Soybean - July 5, 2016

Wisconsin White Mold Risk in Soybean – July 5, 2016

Risk of apothecial presence and subsequent white mold development remains generally low for most of Wisconsin today. Risk has increased slightly across the state over the holiday weekend with some isolated pockets in the northern and south-central areas of the state. The UW Field Crops Pathology crew has been scouting for apothecia in fields in the soybean growing areas of south and central Wisconsin and HAVE NOT found any apothecia. This confirms the generally low risk currently being predicted by the model. Growers near higher risk pockets should monitor the soybean crop for closing canopy and flowering growth stages that may lead to increased risk of white mold. We have seen numerous fields this week already in the R1 growth stage. Be sure to consult the how-to guide for assistance in interpreting this map if you are considering spraying fungicide to control white mold.

This model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold apothecia. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, relative humidity, and wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, this map is generated and indicates areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. For further information on how to use and interpret this risk map, CLICK HERE to download a how-to guide.

Wisconsin White Mold Risk Map – July 1, 2016

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Sclero-cast: A Soybean White Mold Prediction Model

**This tool is for guidance only and should be used with other sources of information and professional advice when determining risk of white mold development. We encourage you to read the model how-to guide which can be downloaded by clicking here**

White Mold Risk - July 1, 2016

White Mold Risk – July 1, 2016

Risk of apothecial presence and subsequent white mold development is generally low for most of Wisconsin today. A few isolated pockets of moderate or higher risk are located around Shawano Co. and north of Barron Co. Soybeans in this area are likely not at the susceptible growth stage. A high-risk pocket is also present in the southeast in western Waukesha Co. Growers near this pocket should monitor the soybean crop for closing canopy and flowering growth stages that may lead to increased risk of white mold. Be sure to consult the how-to guide for assistance in interpreting this map.

This model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold apothecia. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, relative humidity, and wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, this map is generated and indicates areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. For further information on how to use and interpret this risk map, CLICK HERE to download a how-to guide.

Time to Start Watching for White Mold in Soybeans

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Figure 1. Severe white mold in a soybean field.

Figure 1. Severe white mold in a soybean field.

The warm weather over the last several weeks has pushed the Wisconsin soybean crop quickly toward the reproductive growth stages. By the end of the week, most early-planted soybean fields in the southern portion of Wisconsin will begin flowering (R1 growth stage). This growth stage is a critical time to make a fungicide application decision for white mold (Fig. 1; also called Sclerotinia stem rot). Fungicide decisions should be made for this disease between the R1 and the R3 (pods beginning to form on upper nodes) growth stages. After the R4 growth stage control of white mold using fungicides quickly declines. The decision to apply fungicide during this time should be made based on the weather. As discussed in this FACT SHEET and VIDEO, cool (less than 80F) and wet and/or humid conditions during the R1-R3 growth stages can lead to increased risk of white mold later in the season.

Figure 2 illustrates the white mold cycle. Small hardened black structures called sclerotia survive many years in the soil (Fig. 2A). When conditions are cool and wet during the bloom period small mushroom-like structures called apothecia germinate from the sclerotia (Fig. 2B). The apothecia release spores that land on flower petals and germinate (Fig. 2C) allowing the fungus to infect and colonize the soybean plant. As the fungus continues to colonize the inside of the plant, symptoms will begin to develop around the R5 or R6 soybean growth stages. These include wilting plants and paper bag-brown lesions on stems. Eventually new sclerotia of the fungus begin to develop on the plant (Fig. 2D). These sclerotia become the source for future white mold epidemics. Because the white mold fungus needs the open flowers to infect and colonize soybean, it is important to apply a fungicide during this time to protect the plants from infection IF the weather is conducive for the white mold fungus. It can be difficult to determine what “conducive weather” is and if you need to spray.

In an effort to help define these “conducive” conditions, a model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold apothecia. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, relative humidity, and wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, a map is generated (Fig. 3) to indicate areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, the soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. If your fields are at-risk, we recommend to consult your local extension personnel or resources for the best in-season management options for your area. To view and download a handy user guide for the model, CLICK HERE.

For Wisconsin soybean growers, regular updates and commentary regarding risk of white mold can be found on this blog. Color coded, state-wide maps will be posted and our recommendations will accompany these posts. So be sure to check back regularly or subscribe to the blog to receive an automatic e-mail update when a new post has been added. You can subscribe via the window immediately to the right of this window. The inaugural post for 2016 can be viewed by clicking here. 

If you have decided to spray soybeans for white mold, what are the best products to use. Over the last several years we have run numerous fungicide efficacy trials in Wisconsin and in conjunction with researchers in other states. Fungicides that have performed well in multi-state studies can be found in the Soybean Fungicide Efficacy Table. In Wisconsin, we have observed that Endura applied at 8 oz at the R1 growth stage performs well. We have also observed that the fungicide Aproach applied at 9 fl oz at R1 and again at R3 also performs comparably to the Endura treatment. Other fungicide options also include Omega and Proline. You can view results of past fungicide evaluations by CLICKING HERE.

For even more detailed information about white mold you can visit the Crop Protection Network page on white mold . You can also find more information about white mold by clicking here and scrolling down to the white mold section.

To vist other posts on this blog about white mold, click below:

2015 Blog Post

2014 Blog Post

Wisconsin White Mold Risk Map – June 30, 2016

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Damon L. Smith, Extension Field Crops Pathologist, University of Wisconsin-Madison

Jaime Willbur, Graduate Research Assistant, University of Wisconsin-Madison

Sclero-cast: A Soybean White Mold Prediction Model

**This tool is for guidance only and should be used with other sources of information and professional advice when determining risk of white mold development. We encourage you to read the model how-to guide which can be downloaded by clicking here**

Today is the first public posting of the 2016 experimental white mold risk model map. Postings will be conducted on this blog regularly. We suggest that if you are interested in consulting the risk map for Wisconsin, you subscribe to this blog using the window to the right.

White Mold Risk - June 30, 2016

White Mold Risk – June 30, 2016

 

Risk of apothecial presence and subsequent white mold development is generally low for most of Wisconsin today. Warmer than average conditions and limited rainfall over the past month in much of the state has kept the risk low. A few isolated pockets of moderate or higher risk are located around Shawano Co. and north of Barron Co. Soybeans in this area are likely not at the susceptible growth stage. 

This model was developed at the University of Wisconsin-Madison in conjunction with Michigan State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold apothecia. This model predicts when apothecia will be present in the field using 30-day averages of maximum temperature, relative humidity, and wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. Based on these predictions, this map is generated and indicates areas at no (white), low (blue), medium (yellow), and high (red) risk levels. Fields in yellow or red areas have >40% chance of having apothecia present and may be at risk of white mold developing later in the season. Model predictions must be combined with soybean growth stage and canopy characteristics to aid in timing of fungicide sprays. If the model is predicting medium to high risk in your area, soybeans are flowering, and the canopy is somewhat closed, then the white mold risk is elevated. For further information on how to use and interpret this risk map, CLICK HERE to download a how-to guide.

2015 UW Extension Pest Management Update Meeting Series

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General Agronomy

Be sure to get the latest field crop pest management updates, by attending the 2015 PMU Meetings!

Damon Smith, Extension Plant Pathology Specialist

Mark your calendars as the UW Extension’s Pest Management Update meetings are just around the corner (November 9-19). This year’s program will follow the new format established in the 2014 series, with more interaction between presenters and the audience, and participation by Bryan Jensen and Dan Heider with the University of Wisconsin Integrated Pest and Crop Management Program.

We will focus the entire morning (10-noon) on integrated pest management updates by crop (corn, soybean, alfalfa, and small grains). This session will be streamlined to focus on new pesticide registrations, pest updates, and highlight important issues from 2015. After lunch, topics will be more focused on specific updates and diagnostic training. These topics will include:

  • Herbicide resistance update and identification
  • Managing corn rootworms
  • Soybean stem disease identification

These diagnostic and focused trainings were a big hit in 2014 so don’t miss out in 2015!

The full schedule with dates, meeting locations, topics and registration contact information are in the link below. Please register with the host agent at least 1 week prior to the meeting at the location you wish to attend.

Note that due to low turnout in past years, the Arlington location has been dropped from the rotation in 2015. There will only be 7 locations to attend the update meetings, rather than 8 locations as in previous years. Be sure to look at the 2015 schedule included with this article when selecting your preferred date and location.

Please attend the meeting location at which you registered. Each meeting in the series is a separate county-based event and host agents cannot interchange registrant fees or meal counts.

Four hours of CCA CEU pest management credits are requested and available at each location.

The speakers will be extension specialists Mark Renz, weed scientist, perennial cropping systems; Dan Heider, IPM outreach specialist, Bryan Jensen, entomologist, and Damon Smith, field crop plant pathologist.

2015 Pest Management Update Topics:

  • Integrated Pest Management Updates in corn, soybeans, alfalfa, and small grains: Update on new products and/or use of existing products as well as brief highlights of the 2015 pest situations in each crop.
  • Herbicide resistance update and identification: Dan Heider and Mark Renz discuss the herbicide resistant weed situation in Wisconsin and how to identify problematic situations.
  • Managing corn rootworms: Bryan Jensen will take you through identifying corn rootworm problems and how to manage them in field corn.
  • Soybean stem disease identification: Damon Smith will discuss the 2015 soybean stem disease situation in Wisconsin. He will offer tips on how to identify and manage the various stem diseases that cause problems in Wisconsin.

Check out the full meeting schedule at this link.

What Should You Know about Corn and Soybean Diseases as You Prepare for Harvest?

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Damon L. Smith – Extension Field Crops Pathologist, University of Wisconsin

As the fall is approaching and crop harvest plans are being made, it is important to continue to assess disease issues in corn and soybean. These assessments aren’t being made in order to make plans for in-field management, but to improve the quality of grain that is harvested and allow for some educated decision-making for 2016.

Some Diseases to Consider in Corn at Harvest

Figure 1. Gibberella stalk rot on corn. Severe stalk rot on the left and less severe stalk rot on the right.

Figure 1. Gibberella stalk rot on corn. Severe stalk rot on the left and less severe stalk rot on the right.

Now is the best time to begin scouting corn for stalk rot issues and also fungal ear rot potential. Diseases such as Anthracnose stalk rot and Gibberella stalk rot are becoming apparent in corn.  Inspect the stalks integrity on the outside.  Be sure to squeeze the outside of the stalk to gauge the potential severity of the rot on the inside of the stalk.  Cut a few stalks from diverse areas of the field to see how rotted stalks might be. In figure 1, the stalk on the left has a severe case of Gibberella stalk rot, while the stalk on the right is far less rotted.  Fields that had high levels of norther corn leaf blight (NCLB) this season, are going to be more prone to stalk rot due to the added stress of the foliar disease. The more severely rotted stalks are, the more likely they will lodge.  Therefore timely harvest is important. Growers should target harvesting of fields with severe stalk rot before fields that have less stalk rot, in order to minimize harvest losses due to lodging.

Figure 2. Diplodia ear rot.

Figure 2. Diplodia ear rot.

Ear rots can also be an issue at harvest time. Fusarium ear rot, Gibberella ear rot, and Diplodia ear rot (Fig. 2) are just a few that can damage corn in Wisconsin. It will be critical to check fields in the next several weeks in order to make decisions on what fields to harvest first.  Harvest priority should be placed on fields with a high level of ear rot.  As corn stands late into the fall, certain ear rot fungi can continue to grow, damage ears, and cause increases in mycotoxins in grain. The quicker these fields dry and can be harvested, the more likely the losses due to ear rot and mycotoxin accumulation can be minimized.

Soybean White Mold Management at Harvest

Figure 3. Sclerotia of the white mold fungus inside a soybean stem.

Figure 3. Sclerotia of the white mold fungus inside a soybean stem.

In Wisconsin, the main disease to consider when making harvest plans in soybean is white mold. White mold is present in some soybean fields in the state and has caused considerable damage in a few of those fields. Remember that the white mold fungus not only causes stem blight and damage, but also causes the formation of sclerotia (fungal survival structures that look like rat droppings) on and in soybean stems (Fig. 3). These scelrotia serve as the primary source of fungal inoculum for the next soybean crop. They also get caught in combines during harvest. These sclerotia can then be spread in combines to other fields that might not be infested with the white mold fungus.  Therefore, it is important to harvest non-infested soybean fields first, followed by white mold-infested fields, to be sure the combine does not deposit any residual sclerotia in the non-infested fields.  If this is not an option and you must harvest white mold infested fields before non-infested fields, be sure to clean the combine thoroughly between fields.

For more information about white mold management in soybean you can click here and scroll down to “white mold” or watch a video by clicking here.

Identify Corn and Soybean Diseases Now to Make Decisions for 2016

While most of the focus during this time of season is on equipment and calibrating yield monitors, it is important to get an accurate diagnosis on any soybean and corn diseases you are seeing now.  This information will help this winter as you review variety and hybrid trials and make decisions about what you are going to plant in 2016. Have knowledge of the primary disease issues in your fields. This will allow you to choose varieties and hybrids with the best disease resistance package to combat those diseases. Finally, now is a great time to sample for soybean cyst nematode (SCN). For more information on sampling for SCN in Wisconsin, CLICK HERE.