Welcome to Crop Update for February 20, 2007, published by Sangamon-Menard Extension.

IN THIS ISSUE:

• CO-PRODUCT SEMINAR – FEBRUARY 20
• SOIL FERTILITY WORKSHOP – FEBRUARY 22
• TWO PLANT PATHOLOGY PROGRAMS SCHEDULED
• OTHER PROGRAMMING DATES
• GLYPHOSATE RESISTANT WEEDS – A FUNGICIDE STORY?
• SANGAMON-MENARD EXTENSION AUTHORS NEW INSECTICIDE RESOURCE

CO-PRODUCT SEMINAR – FEBRUARY 20

The expansion of ethanol plants in Illinois means that livestock producers will have access to an impressive supply of co-product feedstuffs. However, it is critically important that producers have a handle on: what types of products are available, what the nutritional value of these different products are, what mixing and feeding methods are viable producer options, and what mineral and vitamin supplements are needed when co-products are used. All of these topics will be covered at a workshop to be held on February 20th in Petersburg. The meeting will be held from 6:30 to 8:30 p.m. at Pioneer Hi-Breds (Route 97 just north of Petersburg). Producers may contact Sangamon-Menard Extension to register for the event by calling 632-7491 (Petersburg) or 782-4617 (Springfield).

SOIL FERTILITY WORKSHOP – FEBRUARY 22

A workshop designed to improve “soil fertility expertise” has been scheduled for Feb. 22nd at the Sangamon-Menard Extension office in Springfield. A fee will be charged to attend the program, which will be held from 9:00 a.m. to 2:30 p.m. Lunch and handout materials will
be provided and 5 hours of CCA credit in nutrition management will be offered.

Topics include: Nutrient Placement, Soil Acidity and Liming, Potassium Fertility in Corn and Soybean, Nutrient Deficiencies, The Economics of Soil Testing, Nitrogen and the Nitrogen Cycle, and Amazing Soil Microbes. Producers may contact Sangamon-Menard Extension to register for the event by calling 632-7491 (Petersburg) or 782-4617 (Springfield).

TWO PLANT PATHOLOGY PROGRAMS SCHEDULED

Sangamon-Menard Extension will present two plant pathology sessions in preparation for the 2007 growing season. The first program, entitled the “Central Illinois Corn Plant Pathology Workshop,” will be held at the Sangamon-Menard Extension office located on the Illinois State Fairgrounds in Springfield, Illinois on February 26th . The second program, also held at the Extension office in Springfield and entitled the “Central Illinois Soybean Plant Pathology Workshop,” will be held on March 12th.

Each session starts at 9:00 a.m. and ends by noon. Those attending will learn about both perennial and occasional diseases of corn and beans. In addition, those attending will gain practical experience identifying the diseases noted in the field. Specimens will primarily consist of pressed samples supplemented with photography. Those attending will use on-site dissecting microscopes and hand lenses as they attempt to improve their skill at identifying critical signs and symptoms necessary for in-field diagnostics.

Attendees will also receive valuable resources. Pre-registration is required and the meeting does have a fee associated with it. After February 21st, the fee structure will shift for the Corn Plant Pathology Workshop. After March 7th, the fee structure for will shift for the Soybean Plant Pathology Workshop.

Those interested may contact Sangamon-Menard Extension at (217)782-4216 or (217)632-7491.

OTHER PROGRAMMING DATES

• February 22 – Soil Fertility Workshop
• February 26 – Central Illinois Corn Plant Pathology Workshop
• March 1 – Health Horses in Healthy Habitats (Session 2)
• March 8 – Drainage Law Telenet
• March 12 – Central Illinois Soybean Plant Pathology Workshop
• April 17 – Aquatic Weed Management Telenet

GLYPHOSATE RESISTANT WEEDS – A FUNGICIDE STORY?

Almost twelve years ago, as a new member of what was then the Illinois Cooperative Extension Service (now U of I Extension), I attended a meeting in St. Louis at Monsanto. At that meeting, I listened as my elder colleagues asked questions about Monsanto’s new “RoundupReady Technology.” “What concerns does Monsanto have about the development of glyphosate resistant weeds,” asked my colleagues as we sat in a large auditorium following a tour of the company’s research facilities? “While resistance is not impossible,” commented representatives visiting with us, “the nature of glyphosate will make resistance development in weed populations difficult.”

Just over a decade later, weed scientists now stress the front part of the answer given to my colleagues. While weed resistance to EPSP synthase inhibitors (glyphosate) “may” have been difficult to develop, it was definitely not “impossible.” Today, rigid ryegrass, Italian ryegrass, horseweed, and giant ragweed are all known to be resistant to glyphosate (in various U.S. locations). In addition, palmer amaranth and common waterhemp have recently been added to the glyphosate resistance list. Those last two weed species make me wonder if the story of glyphosate resistance is actually a prequel to our future experience with fungicides.

How did palmer amaranth and common waterhemp develop this resistance to glyphosate, a resistance that if allowed to progress could leave producers with alarmingly few post-emergence herbicide options?

During the University of Illinois’ recent Crop Protection Technology Conference, weed scientists from Georgia (palmer amaranth resistance location) and Missouri (waterhemp resistance location) highlighted the recipe that led to EPSP synthase inhibitor resistance in these two pigweed relatives.

First, they noted, the pollen grains from either species are exceptionally small (about 10 nanometers) and can easily be transferred long distances. This means that genetic material expressing glyphosate resistance can be transported across large distances as well.

Second, waterhemp and palmer amaranth produce hundreds of thousands of seeds and do so within about 40-60 days of germination. In other words, should resistance develop in an Amaranthus (waterhemp, palmer amaranth, pigweed) population, the amount of offspring produced per plant allows resistance to dominate the overall population within a relatively short period of time. Dr. Stan Culpepper of Georgia, noted that glyphosate resistance in palmer amaranth increased from 25 to 75% in the span of only two years.

Third, weed scientists from both states noted that mono-cropping contributed to their cases of resistance development. This allowed certain weed species to reappear each year, providing continual re-exposure of those weed species to a finite list of management tools thus increasing the chances for resistance development.

Fourth, both states noted that intense reliance on only one mode of action – namely EPSP synthase inhibitors/ glyphosate – continually re-exposed those weed species to one mode of action thus promoting selection pressure thus promoting resistance development.

Could the scenario just described be the prophetic story of coming fungicide resistance?

Sangamon-Menard Extension believes the similarities are striking. First, the spores produced by fungi are exceptionally mobile, much like Amaranthus pollen grains, as testified to by the annual movement of some rust diseases throughout the continental United States.

Second, Amaranthus species may produce hundreds of thousands of seeds every 40-60 days, but fungi produce several times that number in spores every 9-10 days given right conditions.

Third, mono-cropping is the trend in our area and in the state. Many individuals expect double-digit increases in the percentage of corn on corn acres this year which means the continual reappearance of certain pathogens.

Fourth, intense reliance on a narrow spectrum of fungicides typifies the fungicide market in corn. Most products are strobilurins, sterol inhibitors, or strobilurin-sterol inhibitor combos.

However, products currently touted for prophylactic use in corn (i.e. use minus evidence of disease or scouting) are only in the strobilurin family. In other words, we are currently focusing on only one mode of action.

The similarities between the patterns that encouraged glyphosate resistance and the current patterns inherent to prophylactic fungicide use in corn are obvious and raise some real concerns about resistance development to strobilurins. However, one major difference between these two stories makes this comparison even more disturbing. Over a decade ago, glyphosate was characterized to me as “difficult to develop resistance to,” but the literature clearly states that fungicides currently touted for prophylactic use (strobilurins) are deemed relatively easy to develop resistance to. Anyone have concerns about future resistance development in the fungicide arena? I think I do, and that is why I think glyphosate resistance is a fungicide story.

SANGAMON-MENARD EXTENSION AUTHORS NEW INSECTICIDE RESOURCE

Integrated Pest Management (IPM) seeks to manage pest populations via utilizing specific “triggers,” typically termed “economic thresholds,” which seek to maximize the producer’s return on management investment. In other words, producers following this practice should not manage a pest too early, when inconsequential pest populations are present, nor should they manage a pest too late, when management of the pest population will only result in a return equal to the cost of management.

Additionally, IPM practices seek to evaluate the exact pest species present, the distribution of that species, and growth/lack-there-of in the population of that species via utilizing various management tools alone or in combination. In other words, IPM does not shun the use of chemicals but it also seeks to expand pest management beyond “chemicals alone.” In addition to management making economic sense, all IPM practices should strive to minimize negative social implications while maximizing environmental stewardship. The later aspect of IPM, namely maximizing environmental stewardship, also stresses the need for product stewardship or what many term “resistance management.” In other words, IPM seeks to minimize the development of resistance to pest management tools.

Sangamon-Menard Extension has been working to improve resistance management efforts via co-authoring a new publication that focuses on insecticide resistance management.

The new publication, entitled Utilizing Insecticide Mode of Action to Combat Insect Resistance to Insecticides, was co-authored by Kelly Cook of the Illinois Natural History Survey and by Matt Montgomery of the Sangamon-Menard Extension Unit.

The publication is divided into three sections. The first page covers general information pertaining to insecticide classification, the nervous system, and resistance management. The back page provides a detailed account, at the cellular level, of how various insecticide families kill or suppress target pests. The publication folds out to provide a color coded chart that highlights which active ingredients are most closely related to one another.

The goal of this publication is to assist producers as they attempt minimize the chances of specific and cross resistance to insecticides. Pests can become resistant to a specific active ingredient, but they may, and often do, become cross resistant. Cross resistance is defined as “resistance to a pesticide that the pest has not previously been exposed to, but that has a mode of action (a method of impact) similar to the pesticide that allowed resistance to develop.” By rotating through the spectrum of color-coded materials (by rotating to products not closely related to one another), producers can minimize the chances of resistance development and increase their product stewardship.

Those interested in obtaining a copy of Utilizing Insecticide Mode of Action to Combat Insect Resistance to Insecticides may contact Sangamon-Menard Extension for details.

University of Illinois Extension provides equal opportunities in programs and employment.

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