Isoxaflutole Use Limited to 12 Wisconsin Counties
By Mike Murray, Wisconsin Department of Agriculture, Trade and Consumer Protection, Pesticide Programs.

As pesticide dealers and applicators and crop farmers may know, rules about using herbicides containing isoxaflutole have been changing in the past couple of years. Let's try to clarify where you stand with regard to these products.

First, a little background. When the Environmental Protection Agency registered these products in 1998, there were concerns about the potential to contaminate both surface and groundwater, and potential effects on non-target crops, including vegetables. Wisconsin, Minnesota and Michigan opted to require the manufacturer, Aventis CropScience, to perform additional studies to demonstrate these products could be used without causing unintended harm. Ultimately, Aventis chose not to register the products in those states.

The current manufacturer, Bayer CropScience, approached the Department of Agriculture, Trade and Consumer Protection in 2013 to revisit the issue. Considering use histories in other states and some additional research, DATCP agreed to allow use of isoxaflutole in eight counties in 2016, with some added restrictions and water monitoring. This year, the list has been expanded to 12, due to difficulties in finding suitable groundwater monitoring sites in the original eight counties.

While the product may be sold by licensed pesticide dealers anywhere in Wisconsin, it can be applied only in these 12 counties. Additional restrictions are required within these 12 counties, so be sure to follow both the product label and the Wisconsin product bulletin:

ColumbiaFond du LacJeffersonSauk

The only isoxaflutole products registered for use in Wisconsin are Corvus Herbicide® and Balance Flexx®. Other isoxaflutole products cannot be used in Wisconsin. A copy of the product labels including the Wisconsin product bulletin is available at Kelly Solutions, where you can search for pesticide product information.

These are the restrictions on use in the 12 counties:

Additional studies are also occurring in Minnesota and Michigan. For more information, call 608-224-4503 or email

Audio (MP3)


Bulk Orders of A3646 Pest Management In Wisconsin Fields
By UW Agronomy Department

A3646, Pest Management in Wisconsin Fields, is a book full of pest management information. This 256 paged book provides pest control ratings for many pesticides in several crops. There is information on pesticides labeled in corn, soybean, forage & pastures, small grains and more.

This book is updated yearly. Bulk orders are by the box (25 in a box) for $260 a box. That is $10.40 a book over a 60% discount per book.

Pest Management in Wisconsin Fields is a great book for handing out to clients at coops and a great door prize.

To order follow the link below.

To Order

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WPS - Employee access to application information.
By Glenn Nice, UW PAT Program

The first season of the new Worker Protection Standard (WPS) rules is here. To help keep track of these new rules the University of Wisconsin Pesticide Applicator Training (PAT) Program has put together some reading on the subject at the link below. Even though we have several new rules to keep track of, many of the old rules are still in place.

One such rule is the requirement to make application information available to employees. This information has to be made available at a central location. This is an area where employees will congregate or come in frequent contact, such as the breakroom. This information has to be made available by the employer when any worker or handler is on the establishment and an application of a pesticide with a Restricted Entry Interval (REI) has been made in the past 30-days.

Information that has to be displayed are:

Part of the new rules is you have to provide paper copies of the Safety Data Sheet (SDS) for each pesticide applied on your farm, forest, greenhouse or nursery.

Example of display information.

In this same location, you must also hang the Environmental Protection Agencies WPS safety poster. Keep in mind there will be a new poster in 2018 with additional information on it. They are typically available at any supply company.

Example of central location display.


How to Complay to the 2015 Revisions

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DATCP Proposes Special Local Need Registration for Two Pesticides in Wisconsin
By Steve Tomasko, UW PAT Program.

Wisconsin growers of carrots and lima beans may get a couple of extra tools to help control pests this growing season. The Wisconsin Department of Agriculture, Trade and Consumer Protection is proposing a “special local need (SLN)” pesticide registration for the use of Reflex® on lima beans and Nimitz® on carrots. Reflex® is an herbicide and Nimitz® is a nematicide.

The active ingredient in Reflex® is fomesafen and is made by Syngenta. The the active ingredient in Nimitz® is fluensulfone and the product is made by Adama.

A special local need (SLN) registration (also called a 24(c) registration) allows states to expand or limit the uses of certain registered pesticides within their jurisdictions. The state will authorize a SLN registration to address an existing or imminent pest situation. The pest situation must be a special local need within the state that cannot be controlled by a currently registered product.

In the case of lima beans, that pest situation is the control of two weeds: Palmer amaranth and nightshade. Palmer amaranth is often resistant to herbicides and each plant can produce 100,000 seeds and can quickly take over a field. Nightshade produces toxic berries late in the season. Processors may turn down an entire field of lima beans if nightshade is present to avoid risking contamination. There are currently few herbicide options available to lima bean growers, and the current registered herbicides do not provide broad, season-long control.

For carrot growers, Nimitz® would help control certain nematodes. Nematodes are tiny (often microscopic) worm-like organisms that live in the soil. Some nematodes harm crops and in carrots, can reduce yields and deform carrots. One of the main products used to control these pests in carrots is currently unavailable due to production outages and other products are less effective. Nimitz® is already used in the state on other vegetable crops but not currently labeled for use on carrots.

If approved, both these SLN registrations will expire December 31, 2021.

More Information about the SLN Process

Audio (MP3)


Water Soluble Packets (WSP)
By Glenn Nice, UW PAT Program.

The Environmental Protection Agency (EPA) and manufacturers of pesticides are always looking and developing new ways to reduce occupational exposure. One such way is through the use of closed mixing and loading systems. Not unlike using a fuel pump at a gas station, where you never come in contact with the gasoline, these closed mixing and loading systems are designed to minimize potential exposure. They are designed so that mixer and loader does not come in contact with the pesticide.

Two such systems include "lock-n-load" loading systems and water soluble packets (WSP). WSP are packets of preweighed amounts of the concentrated pesticide in a dry form that is engineered to dissolve in water. Essentially, the packet is dropped into a tank of agitated water and the packet dissolves in the tank water releasing the pesticide.

In recent studies by the Agricultural Handler Exposure Task Force, several practices were reported on that potentially increased exposure. Some of these practices were included in a letter to companies using WSP as a delivery methods; including using high pressure water on the packets and intentionally breaking the bags before mixing. I have personally observed the opening of the WSP to extract small amounts from the bag. These observations of the task force have led to the EPA to address the improper use of the products. The labels of products that use WSP as a delivery method will be required to standardize the language in the "Directions for Use" sections.

The following language below will appear on these labels and was provided by the EPA's Office of Pesticide Programs: Follow these steps when handling pesticide products in WSPs.

  1. Mix in Spray tank only.
  2. Handle WSP(s) in a manner that protects package from breakage and/or unintended release of contents. If package is broken, put on PPE required for clean-up and then continue with mixing instructions.
  3. Keep the WSP(s) in outer packaging until just before use.
  4. Keep the WSP dry prior to adding to the spray tank.
  5. Handle with dry gloves and according to the label instructions for PPE
  6. Keep WSP intact. Do not cut or puncture WSP.
  7. Reseal the WSP outer packaging to protect any unused WSP(s).

Mixing Instructions

Follow the steps below when mixing this product, including if tank mixed with other pesticide products. If being tank mixed, the mixing directions 1 through 9 below take precedence over the mixing directions of the other tank mix products. WSPs may, in some cases, be mixed with other pesticide products so long as the directions for use of all mixed products do not conflict. Do not tank mix this product with products that prohibit tank mixing or have conflicting mixing directions.

  1. If a basket or strainer is present in the tank hatch, remove prior to adding the WSP to the tank.
  2. Fill tank with water to approximately one-third to one-half of the desired final volumes of spray.
  3. Stop adding water and agitation.
  4. Place intact/unopened WSP(s) into the tank.
  5. Do not spray water form a hose or fill pipe to break or dissolve the WSP(s).
  6. Start mechanical and recirculation agitation from the bottom of tank without using any overhead recirculation, if possible. If overhead recirculation cannot be turned off, close the hatch before starting agitation.
  7. Dissolving the WSP(s) may take up to 5 minutes or longer, depending on water temperature, water hardness and intensity of agitation.
  8. Stop agitation before tank lid is opened.
  9. Open the lid to the tank, exercising caution to avoid contact with dusts or spray mix, to verify that the WSPs have fully dissolved and the contents have been thoroughly mixed into the solution.
  10. Do not add other allowed products or complete filling the tank until the bags have fully dissolved and pesticide is thoroughly mixed.
  11. Once the WSP have fully dissolved and any other products have been added to the tank, resume filling the tank with water to the desired level, close the tank lid, and resume agitation.
  12. Use the spray solution when mixing is complete.
  13. Maintain agitation of the diluted pesticide mix during transport and application.
  14. It is unlawful to use any registered pesticide, including WSPs, in a manner inconsistent with its label.

The goal of WSPs is to assure that you do not come into contact with the pesticide inside. Breaking the packet open, using high pressure water to break the packet open (this can cause splash back and your aim may not be that great) or letting the packets get wet before dropping them into the tank kind of defeats that purpose. I have heard concerns or complaints regarding the mixing or dissolving of these products. Agitations is most definitely required. If you experience problems with mixing please contact your supplier or the company directly. Always read and follow label instructions.

Audio (MP3)


Know Your Enemy: The Importance of Proper Pest Identification
By Steve Tomasko, PAT Program

A major key to effective pest control is to know what pest you’re trying to get rid of. That might seem obvious, but it’s not always so easy. Pests can look different as they go through their life cycles. For example an immature beetle may look like a caterpillar or worm. The control methods, whether chemical or not, can vary widely depending on what the pest is.

In the world of insects, one critter can easily be mistaken for another. It’s possible that the “pest” you try to control is actually a beneficial organism, harmless, or only a temporary problem. When we deal with plants as pests (weeds), knowing the enemy is very important to choosing what type of herbicide to use and the best time to use it.

comparison of 5 pest worms

Which of these things is not like the other? See if you can figure out which two of the five critters above are caterpillars before looking at the answers. (1: caterpillar of a corn borer, 2: larvae of a saw-toothed grain beetle, 3: caterpillar of an Indian meal moth, 4: larvae of a fungus gnat, 5: larvae of a lacewing.


When it comes to plant diseases, since you almost never see the actual pest organism (usually fungi, but also bacteria, viruses or nematodes), you need to rely on the symptoms the pest is causing. These symptoms (just like symptoms in humans) can often look similar or be confused with damage not caused by a living organism.

None of us can be experts in insect, weed and plant disease ID (or if you are an expert in all three, there’s probably a high-paying job out there for you!). Luckily, there are many resources available to help identify pests.

There are many identification guides online; however, be cautious, not all information posted on the web is reliable (sometimes information may simply steer you toward one particular product). A good place to get information is from universities, extension services and government agencies. You can often get field guides and other print material at your library or Cooperative Extension Office.

There is a wealth of information out there, but I don’t want to flood the end of this article with too many resources. I will mostly focus on tools available from the University of Wisconsin and Extension systems.

Your first step in getting help can often be your local county Extension office. The fundamental purpose of the UW-Extension program is to give aid the people of Wisconsin by extending the boundaries of the university to the boundaries of the state and beyond; providing information to people wherever they live and work. Extension offices may have printed information for your specific pest, they often have someone that can help you identify your pest or can give you contact information to someone who can. You can find your local county extension office at the following website: County Extension Offices


The UW-Madison Insect Diagnostic Lab, capably staffed by PJ Liesch, offers an online insect ID tool at: In addition, you can call or email the lab (and send digital pictures). The home page for the lab ( provides information on how to submit samples for identification (both digital images and physical specimens).

Although more in the DIY category, the following two websites have many pictures and lots of information about insects.


What’s That Bug?:

Weed Identification:

Again, your local Extension office can be a good source to check with for weed ID. The Weed Identification and Management website ( has an online weed ID tool.

Plant Diseases:

For plant diseases, the Plant Disease Diagnostic Clinic at UW-Madison ( has a wealth of brochures, fact sheets and other information online. In addition, you can send samples of infected plants to the lab for diagnosis. There are fees for this service. Make sure you consult the website for instructions on how to properly submit samples.

Audio (MP3)


Corn Rootworm Resistance to Bt Corn
By Steve Tomasko, PAT Program.

Much of the corn planted today has been genetically modified to help protect the crop against corn rootworm and other lepidopteran (moth) pests. But the development of resistance by rootworms has raised concerns about the continued effectiveness of these crops. This has prompted the U.S. Environmental Protection Agency (EPA) to step in. The EPA now requires the companies that make these modified corn hybrids conduct more aggressive education campaigns encouraging growers to practice integrated pest management (IPM) techniques to help reduce the growth of resistant pest populations.

comparison of 5 pest worms

Above is a side-by-side comparison of adult specimens of the southern corn rootworm (Diabrotica undecimpunctata howardi), northern corn rootworm (D. barberi) and western corn rootworm (D. virgifera virgifera). (Image courtesy of R.L. Croissant,


BT Corn Hybrids and Pesticide Resistance

BT corn hybrids contain a toxin produced by a natural soil bacterium, Bacillus thuringiensis (Bt). These corn hybrids are regulated by the EPA like pesticides. Four different Bt proteins that are labeled and marketed for rootworm control. Bt proteins are marketed in one of four ways, 1) Single traits 2) Stacked traits 3) Pyramid traits and 4) Stacked pyramid traits. Single traits (which are not readily available in today’s market) use a single Bt toxin and target one insect. Stacked Traits contain two Bt proteins, each targeting a different species of insect. Pyramid traits have multiple Bt toxins (with different modes of action) and target a single insect. Pyramid Stacked hybrids have multiple Bt toxins for controlling corn rootworms and other above ground insects.

According to the USDA, plantings of Bt corn grew from about 8 percent of U.S. corn acreage in 1997 to 79 percent in 2016. These corn hybrids have, in most cases, provided reliable control of rootworms. However, western corn rootworms have demonstrated field-evolved resistance to some of the Bt toxins.

I wrote about the problems of pesticide resistance in a two part article in earlier PAT-CHAT Newsletters [Part 1 and Part 2]. Even though the pesticides are not being “sprayed” on the corn, the mechanism of resistance works the same. The constant exposure to the Bt toxin selects for resistance in pest populations.

The EPA cites the “red zone” for rootworm resistance as portions of Iowa, Illinois, Nebraska, western Indiana, southwestern Wisconsin, southern Minnesota and eastern South Dakota. EPA officials say 70% of corn acres in the red zone and 50% of all other acres should use IPM techniques such as crop rotation to help slow the spread of resistance.

EPA Guidelines

The EPA initially proposed rules that would have included enforceable planting requirements for farmers who buy and plant Bt. However, the final ruling instead puts the onus on Bt corn-producing companies (such as Monsanto, Dow AgroSciences and Syngenta) to conduct more aggressive education campaigns that encourage growers to practice resistance avoidance tactics such as crop rotation, pyramided Bt products and the use of non-Bt corn hybrids with soil insecticides. There are also requirements for the companies to more closely investigate reports of resistance.

Following are the specific requirements in the EPA guidelines:

While we humans keep finding new technology to combat the pests, it seems the pests keep finding ways around it. But by using multiple techniques (IPM strategies) we can help control resistance and keep growing the crops we need to feed the world.

Audio (MP3)


Times are Changing, but Illegal Pesticide Residues Remain the Same
By Glenn Nice, UW PAT Program.

A not so recent news release by the Oregon Health Authority caught my attention. The news release reported illegal pesticide residues found in marijuana products resulting in a recall of products of a specific batch number. The pesticide in question was Spinosad, a mixture of the biopesticides spinosyn A and D.

Like all pesticides registered by the EPA there are tolerance levels set by the current body of information regarding the pesticide in question. In the case of Spinosad, a pesticide created by a soil bacterium, the tolerance in marijuana products is 0.2 parts per million (ppm). The amounts found in the products in question were reported to be between 22 and 42 ppm. This news caught my eye for several reasons.

The first thing is times are changing. Whether you agree or disagree on the legalization of marijuana, many years ago when I was studying to be a Weed (funny) Scientist, I never thought that we would be looking at weed control in marijuana, but some of my colleagues in other states are doing research on this very topic. However, with the legalization leading to the legitimization of growing marijuana as a crop in some states, the EPA has had to look at tolerances. And some pesticide manufacturers have sought labels for use in this crop.

The second thing this brings up is the important topic of pesticide residues and tolerances. When a pesticide is used, it does not just disappear, it remains for a period of time. However, as soon as it is sprayed, microbes, chemical processes and sunlight start to dismantle the pesticide molecules into smaller parts or break it down. As the pesticide breaks down, over time the amount of the pesticide is reduced. Given enough time only trace amounts can be detected and eventually not detected at all.

The speed that this process occurs is highly dependent on the properties of the pesticide and also on environmental variables (such as heat, moisture, soil pH, etc.) where it was released. The time frame that this occurs is often quantified as a “half-life.” The half-life is the amount of time it takes to break down or degrade amount of something to half the original amount.

Based on the current body of scientific information the EPA sets pesticide tolerances. These are the maximum amounts of that pesticide that are allowed and are deemed to have no identifiable health effects. Products that have greater than this set tolerance cannot be sold in in the market.

The tolerance is determined taking into account that a person may come in contact with the same pesticide in more than one way. For example, a person may come in contact with a pyrethrin on produce, but then also be exposed to the family pet who wears flea collar. The tolerance is further reduced taking into account children may come in contact with the pesticide.

Tolerances are expressed in parts per million (ppm). A ppm is 1 part in 1,000,000 parts of something. For example, one grain of rice thrown in a pile of 1,000,000 grains of rice. Tolerances are listed in the Code of Federal Regulations Title 40, subchapter E, part 180. Below is a table showing a few examples. Tolerances also include metabolites and degrades—the breakdown components of the pesticide in question.

Table 1. Some examples of EPA tolerances to pesticide residues. To see more go to Title 40, Chapter 1, Subchapter E, part 180 or follow the link below.

Although the EPA sets tolerances, it is the United State Department of Agriculture (USDA) that enforces tolerances for meat, poultry and some egg products and it is the U.S. Food and Drug Administration (FDA) that enforces tolerances on the rest of our food [About Pesticide Tolerances, EPA].

The USDA’s Agricultural Marketing Service and the Science and Technology Program carry out sampling of commodities for pesticide residues and post them in an annual summary each year.

What does all this mean for an applicator? Failure to calibrate equipment, follow label directions, or accidents can lead to applying too much pesticide. This can lead to higher than labeled amounts of pesticides on harvested products or in the environment, possibly resulting in higher than the tolerated residues. Harvested products that have illegal residues can be confiscated and fines can be issued. More tragic, and the reason for tolerances, is that the people who buy harvested products could be hurt.

Labels provide maximum rates based on residue studies and how that specific pesticide acts in a plant or environment that it is being introduced to. Pesticides that are labeled for use in crops will have a preharvest interval (PHI), a period of time between the last application and the harvest of that product. Which brings us to; “Always read and follow the label when using pesticides.”

About Pesticide Tolerances


OHA issues health alert for pesticide-tainted marijuana

NPIC, Spinosadgen Factsheet


Audio (MP3)


Pesticide Labels from the Internet
By Steve Tomasko, UW PAT Program.

With the ability to get almost any information from the internet these days, you might wonder about pesticide labels. While true that you can find labels on many websites (EPA, manufacturers, retailers and more) and that information may be useful, you are still bound by the instructions on the label that is found physically attached to the product you’re using. That said, this could change in the future.

Electronic or Web-Distributed Labeling

The U.S. Environmental Protection Agency (EPA) has conducted a pilot project and is moving ahead with Web-distributed Labeling (WDL). This could change what constitutes the “official” pesticide label that an applicator must follow to comply with federal and state regulations.

In 2014, the EPA launched the pilot project for WDL. The EPA says WDLs could help pesticide users better understand and comply with pesticide labeling. Other benefits the agency sees include:

Currently, pesticide manufacturers have the go-ahead to produce WDLs. Producing them is voluntary. The EPA has discussed web-distributed labeling with several registrants, but none have started the process yet. When EPA receives a formal application to add a WDL, it will work with states and extension to let regulators, educators, and applicators know about its availability and how to get additional labeling from a website.


Part of the reason no companies have yet gone ahead with a WDL is they may be waiting for a related, but separate EPA program called “SmartLabel” to advance out of its pilot project phase. Currently, manufacturers must submit paper or PDF files when registering labels. The SmartLabel system will make that process electronic. One of the goals of the SmartLabel system is to make label information more quickly available to the public in an easily searchable format. SmartLabel will make the label approval process faster and more efficient by creating standardized label sections for all pesticide labels.

If you’re confused by the difference between the WDL program and SmartLabel, don’t worry. Basically the SmartLabel system is for companies and the WDL will be aimed at the end user—the applicator. But the two should mesh to provide labels that are more streamlined and focused for the user (for example, a WDL could provide the applicator with state-specific regulations for that product).

The Upshot

When WDLs become a reality, both the container labeling and the WDL will be considered legally valid. The EPA says the overall goals are to make the most up-to-date version of pesticide labels available to users quickly and to improve applicators’ understanding of, and compliance with, instructions on those pesticide labels.

Although as we’ve noted above, currently, labels you get from the internet are not “official” they still can be useful (especially when researching products before you buy them). You can often find labels on the manufacturer’s website. Following are a few other places to go to find pesticide labels.

CDMS Label Database

You will need to sign up or login to use this database. Sign up is free.

Pesticides registered in Wisconsin

Web-distributed Labeling

SmartLabel project

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