Martin Chilvers and Ray Hammerschmidt...Attention county educators and interested soybean growers. Drs. Allen Wrather, University of Missouri, and Steve Koenning, North Carolina State University are conducting a national survey of soybean yield loss for the United Soybean Board (USB). The purpose is to provide information to assist agencies like USB to decide which research projects to support and to help scientists focus and coordinate research efforts.

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By Mike Staton... Planting delays and the cool weather have some producers wondering if their soybeans will reach physiological maturity before the first killing frost occurs this fall.

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By Christy Sprague... Making one more glyphosate application in Roundup Ready soybeans is tempting when weeds are poking through the soybean canopy. However, it is important to remember that there is a maximum soybean growth stage for which glyphosate can be applied to Roundup Ready (glyphosate-resistant) soybeans.

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Martin Chilvers, Janette Jacobs, Ray Hammerschmidt and Jan Byrne... Now that flowering has begun and canopies are beginning to close, soybeans will be at risk to white mold. White mold is caused by the fungus Sclerotinia sclerotiorum. The fungus overwinters in crop debris or soil as sclerotia with an appearance similar to mouse droppings.

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By Martin Chilvers, Janette Jacobs, Ray Hammerschmidt and Jan Byrne... As part of the Integrated Pest Management - Pest Information Platform for Extension and Education (IPM-PIPE) funded by the North Central Soybean Research Program and the USDA, MSU plant pathologists are actively scouting legumes for soybean rust, legume viruses and diseases.

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By Fred Warner... Now is an ideal time to begin scouting soybean fields for symptoms caused by the feeding of soybean cyst nematodes (SCN). Symptoms typically become obvious in July and will remain evident until the plants senesce after frost.

[Read the rest of this article...]

By Ned Birkey... Will 2009 see a verified 100 bushel soybean yields in Michigan? Last year was the most exciting year of the three years of the Michigan soybean yield contest with a top yield of 85 bushels per acre.

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By Mike Staton and Darryl Warncke... Manganese deficiency is common in Michigan and can cause yield reductions if not corrected. Because of this, soybean growers need to be able to identify manganese deficiency symptoms and know the best strategy for correcting them. Manganese deficiency typically occurs in muck soils or dark-colored sands with pH levels above 5.8.

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By Chris DiFonzo... Soybean aphids were found on the MSU campus on Tuesday, June 2, in an early-planted research plot. Beans were nearly V1 (first trifoliate expanded). Aphids were actually fairly common along the edge of the field, with perhaps 5 percent of the plants with an aphid. Aphids tend to land on plants near clean-cultivated borders.

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By Christy Sprague... No-till soybean production in Michigan relies almost exclusively on glyphosate for preplant and postemergence weed control. While glyphosate continues to provide excellent control of most weeds, timely applications before planting and after soybean emergence are necessary to ensure the best growing conditions for your soybean crop.

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Christina DiFonzo, Entomology

Leaves are emerging on buckthorn shrubs in Michigan. This is also the time that soybean aphid colonies are found on the newly emerged leaves. Despite the record fall flight of soybean aphid back to buckthorn in 2008, thus far in spring 2009 I have not found aphids around the MSU campus.

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By Mike Staton and Darryl Warncke -- Soybeans will respond to good soil fertility and plant nutrient management. The keys to success are managing soil pH in the proper range, identifying crop nutrient needs and applying the required nutrients at the optimum rates and times.

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By Kurt Thelen... Recent research conducted in the North Central Corn Belt suggests that soybean planting populations may be able to be dialed back somewhat without compromising yield, or more importantly, profitability. Research conducted throughout the Midwest is showing that a final harvest population of 100,000 plants per acre is generally sufficient to achieve maximum yield.

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By Mike Staton... Michigan soybean growers will be able to access timely crop and pest management information through a toll-free, soybean hotline sponsored by MSU Extension and the Michigan Soybean Checkoff. The hotline will be up and running on Friday, April 24 and can be accessed by dialing (888) 201-9301.

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By Fred Warner and Angela Tenney... This will be the fourteenth consecutive year the Michigan Soybean Promotion Committee (MSPC) has sponsored the soybean cyst nematode sampling program in partnership with Diagnostic Services at MSU. Like many new programs, it got off to a rather slow start as only 73 samples were submitted for soybean cyst nematode analyses in 1996.

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By Mike Staton... University researchers around the Corn Belt have shown that early planting is critical to producing high soybean yields. The ideal planting time for soybeans is basically the same as it is for corn; the first week of May for the lower half of the Lower Peninsula.

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By Diane Brown-Rytlewski... As growers strive for higher yields, there is a tendency to push planting dates to capture yield increases that are associated with early season planting. Seed treatment for soybeans is recommended to control seed-borne infection, to improve stand emergence, and when seed quality is poor.

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Diane Brown-Rytlewski...There is a great resource for soybean producers available at the Plant Management Network at the Focus on Soybean website. The site contains webcasts with PowerPoint slides narrated by university researchers from around the country, with presentations related to crop production, and crop protection.

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Mike Staton...Reducing harvest losses is a simple and effective way to increase soybean yields and profitability. Losses of 10 percent are typical and can reach 15 percent. With careful maintenance and operation, harvest losses can be maintained at three percent. Reducing harvest losses from 10 to three percent in a 45 bushel per acre soybean crop will increase the marketable yield by 3.1 bushels per acre.

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Jan Byrne and Carmen Medina-Mora...This summer the weather in Michigan, especially June, could be described as a “cornucopia” of climatic changes. Above all the changes, we experienced unseasonably rainy days and chilly nights, which have resulted in a delayed development of many plants, vegetables, and crops, including soybeans. As the month of July rolled in, we finally had warmer temperatures.

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Diane Brown-Rytlewski...So far, soybean rust hasn’t spread very quickly this year in part due to unfavorable weather conditions down south. Soybean rust has been confirmed on soybean in several southern states, including Texas, Alabama and Florida. Since the first of this year, soybean rust has been reported in two counties in Alabama; one county in Georgia, 16 counties in Florida; three counties in Louisiana; one county in Mississippi, and four counties in Texas, mainly on kudzu.

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Diane Brown-Rytlewski...High market prices for both corn and soybeans this year are once again tempting growers to consider applying fungicides in the absence of disease. Whether or not a yield increase will result continues to be a topic of many lunch counter discussions, and among plant pathologists.

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Diane Brown-Rytlewski...Can you help us with our search for soybean killers? We need to collect isolates of the fungus that causes Soybean Sudden Death Syndrome (SDS) from grower fields for a research study funded by the Michigan Soybean Promotion Committee. The first part of the project is to collect plants with symptoms of SDS from grower fields.

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Dale Mutch...On Wednesday, July 2, near Charlotte, Michigan, located in the central part of the state, there was a terrible hail storm that devastated soybean and corn fields. These pictures show a field of plants with no foliage on them. Throughout my 28 years with MSU Extension, I have never seen damage this severe from hail. At the MSU W. K. Kellogg Biological Station we were hit by hail, however, nothing in comparison to these fields near Charlotte.

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Diane Brown-Rytlewski...United States Environmental Protection Agency (EPA) issued a Section 3 registration for the use of Alto® fungicide in soybeans to control Asian soybean rust. Alto previously had a Section 18 registration. Alto, a systemic triazole fungicide containing the active ingredient cyproconazole is manufactured by Syngenta Crop Protection. Triazoles provide some residual curative activity.

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The Pesticide Application Technology for Soybean Rust and Soybean Aphids is a factsheet put together by the Michigan State University Extension. The factsheet covers the application of peticides to soybean rust and soybean aphids; including management and sprayer characteristics.

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Diane Brown-Rytlewski...Links to each chapter are available at the site, and individual chapters can be downloaded. Foliar applications of fungicides to the soybean canopy is the standard disease management practice to limit yield losses due to soybean rust for the foreseeable future. This book reviews the factors involved in making fungicide spray decisions and basic fungicide information, including mode of action, application, and use strategies.

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Kurt Thelen...Last week’s heavy rains have resulted in isolated areas of severe ponding in parts of the state. This problem has left growers struggling with the question of whether or not to replant water damaged stands. The replant decision is further complicated by the fact that we are now nearing the end of the viable planting season window for corn and soybean.

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Kurt Thelen...It appears that most of Michigan’s emerging corn and soybean crop has made it through the recent cold snap in fairly good shape. Regional reports from MSU Extension educators located in the primary corn and soybean growing areas indicated overnight temperatures in the low 30s, and upper 20s the past week. Most of the state did not quite reach the critical 28°F threshold and avoided significant frost injury.

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Christy Sprague...Postemergence herbicide applications for weed control in soybean are quickly approaching. There are several things that should be considered to maximize weed control with glyphosate from these applications in Roundup Ready soybean. Following these guidelines can help reduce the risk of glyphosate failures, as well as reduce the chances of lower soybean yields due to weed competition.

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Darryl Warncke...Manganese (Mn) is one of the more challenging micronutrients to manage and is the one most likely to be deficient on many field crops. MSU Extension bulletin E-486 is an excellent resource for information on manganese and the other secondary and micronutrients. The field crops most likely to show Mn deficiency are dry beans, soybeans, sugarbeet, wheat and oats.

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Mike Staton, Diane Brown-Rytlewski, and Kurt Thelen...Early detection and diagnosis of soybean emergence problems is always important to achieving high yields. However, early season-scouting is even more important this year due to a reduction in seed quality. Soybean emergence ranges from six days under ideal conditions to 14 days under more challenging soil conditions. Conditions that can lead to delayed or uneven emergence include: cold soil temperatures, excess soil moisture, inadequate soil moisture, soil crusting, improper seeding depth or uniformity, poor seed-to-soil contact, insect feeding and disease infestations.

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Christy Sprague...Driving around the state, I have noticed several no-till fields that still have carpets of winter annual and some newly emerged early summer annual weeds, like common lambsquarters and giant ragweed. With soybean planting in full swing, it is extremely important that these weeds be controlled prior to soybean emergence. Ideally, these weeds should have been controlled prior to planting, but because many of these fields have already been planted it is important to control these weeds prior to soybean emergence.

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Christina DiFonzo...In the last Field CAT Alert, I noted the presence of Asiatic garden beetle grubs in many fields in St. Joseph County. In the next few weeks as corn and soybean emerges, the first indications of grub damage will be apparent. Grubs, the larvae of scarab beetles, are a growing concern in field crops in Michigan and surrounding states. Early in the season, grubs feed on germinating seeds and small plants, reducing plant stand.

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Christina DiFonzo...On May 7, I found one soybean aphid colony on my favorite MSU buckthorn, so as always aphids made it through the winter. In comparison, in springs of bad aphid years, this shrub has had 15 to 20 colonies.

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Christy Sprague...The use of postemergence (POST) glyphosate in Roundup Ready soybeans has been the primary weed control program used by many Michigan soybean growers. While this system has seemed to simplify weed management, relying on total postemergence herbicide programs can be difficult to manage if not properly implemented. The flexibility in application timing that glyphosate offers may make it easier to control larger weeds, however the benefits of early-season weed control to protect crop yield can be lost if applications are not made in a timely manner.

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Christina DiFonzo...Last season was a banner year for worms and beetles, but where were the soybean aphids? Chris DiFonzo, the self-proclaimed soybean aphid queen (that’s me) predicted an aphid outbreak for 2007.  Where was the outbreak? Will the prediction for 2008 be equally as accurate? Let’s recap the 2007 season. In the winter of that year, entomologists in the Midwest predicted a soybean outbreak. That prediction was based on two lines of evidence: suction traps and egg numbers.

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Mike Staton...The widespread occurrence of green stem disorder last fall adversely affected the quality of soybean seed farmers will plant this spring. The green stems delayed harvest operations exposing the seed to repeated wetting and drying cycles, which reduced the thickness and integrity of the seed coats. When seed was finally harvested, it was difficult to adjust combines to be both gentle to the tender seed coats and also aggressive enough to remove the green plants.

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Mike Staton...The following checklist summarizes management practices that are proven to contribute to high-yielding soybeans...Uniform seed spacing in the row will improve yields. Small seed will plant more evenly and will experience less mechanical damage than large seed when planted with a drill equipped with a fluted metering system. Always calibrate your drill by seeds per foot of row or seeds per acre. Recalibrate whenever seed size changes.

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Joe Armstrong and Christy Sprague...No-till soybean production in Michigan relies almost exclusively on glyphosate for preplant and postemergence weed control. While glyphosate continues to provide excellent control of most weeds, timely applications before planting and after soybean emergence are necessary to ensure the best growing conditions for your soybean crop. The following recommendations are based on MSU research funded by the Michigan Soybean Promotion Committee (MSPC).

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Christina DiFonzo...The North Central Soybean Research Program (NCSRP) recently produced a new Soybean Aphid Research Update. The update was created based on interviews with soybean entomologists and plant breeders from across the Midwest and highlights NCSRP-funded projects on aphid suction trapping, biocontrol and host plant resistance.

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Fred Springborn and Tim Harrigan...As many folks have acquired new or newer equipment this year, or are planting soybeans for the first time, here are some thoughts and suggestions on planting equipment before you go to the field.

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Ned. Birkey...Although Asian soybean rust was not positively identified in Michigan in 2007, it was found in nearby Ontario. Many farmers in Michigan did spray for weeds, and possibly spider mites, soybean aphids and perhaps tank-mixed manganese. Now that spring has arrived, this is an excellent time to “tune up” field crop ground sprayers.

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Christy Sprague and Wesley Everman...The 2008 Weed Control Guide for Field Crops, Extension Bulletin E-434 is now available online at http://www.msuweeds.com/publications/2008_weed_guide/. It is also available in print at the MSU Extension Bulletin office by calling (517)353-6740 or your county Extension office.

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Mike Staton, Kurt Thelen and George Silva...The following checklist summarizes management practices that are proven to contribute to high-yielding soybeans. The practices are organized chronologically, beginning with the fall before the soybeans will be planted. This list can be used to identify opportunities for increasing soybean yields.

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Diane Brown-Rytlewski...As the soybean rust sentinel plot scouting draws to a close for 2007, there has been no soybean rust detected in Michigan thus far. Although storm systems in the next week or so may bring spores to the Great Lakes region, many of the soybeans are at R6 (full seed) in Michigan. Even if rust were to appear, soybeans have reached the stage where treatment is unnecessary. As in previous years, there have been a couple of positive detections of soybean rust at a moderate level in spore traps.

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Diane Brown-Rytlewski...Many areas of Michigan are suffering from severe drought. I just listened to an hour of reports from extension educators across the state talking about how much of the state’s corn crop has been lost. However, there still seems to be some hope for a decent crop of soybeans. Some areas of the state have received a bit of rain recently, although predictions of above normal temperatures and lower than normal rainfall continue. Growers are all hoping for the best, looking for ways to squeeze out more yield.

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Diane Brown-Rytlewski...Over the last few years, the number of fields reported with symptoms of soybean sudden death has been increasing. The first few reports of suspected soybean sudden death are trickling in, so this is a good time to review the disease symptoms and management. Soybean sudden death is caused by a fungus, Fusarium virguliforme (formerly F. solani f.s. glycines). Research shows that there is a definite relationship between soybean sudden death and the soybean cyst nematode.

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Diane Brown-Rytlewski...Soybean rust has recently shown up in the southwest corner of Arkansas, the furthest north it has made it so far this season. Rust has shown up earlier and more extensively in Texas and Louisiana this year. Rust has also been confirmed in plantings of yam bean (jicama) in Mexico. Rust development and spread in these locations as opposed to rust found in Florida or Georgia is of more concern to us in Michigan, because the majority of storms that could carry the rust northward to us originate in the Gulf of Mexico.

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Diane Brown-Rytlewski...Some growers may be contemplating the use of foliar fungicides on hybrid corn this season, due to higher market prices for corn, marketing of fungicide products, or concern over increased disease risk from planting corn-on-corn. Growers may have similar thoughts of applying foliar fungicides to soybeans due to higher market prices.

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Kurt Thelen...Manganese deficiency is the most common crop micronutrient problem in Michigan, particularly in soybeans and wheat. The availability of manganese to the plant generally decreases as soil pH levels increase. Consequently, soybeans grown in the calcareous soils of Michigan’s Thumb area and in the lake-bed soils in Michigan’s Southeast Lower Peninsula, historically have been found to be deficient in manganese.

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Ron Gehl...Manganese deficiency is the most common micronutrient issue found in Michigan row crop production. Soybeans and wheat are the two field crops most likely to develop manganese deficiency, although deficiency may also be found in corn and sugar beets. Manganese deficiency appears as yellowing between the leaf veins (interveinal chlorosis) of corn, soybeans, and sugar beets, and as yellow-green striping in wheat (see photos).

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Christina DiFonzo...As in 2005 Monroe County, this summer we have at least one area, in eastern Saginaw County, where soybean aphids are over threshold (view photos). The fields I saw were specifically near Frankenmuth. I did not see buckthorn in the immediate area, but this part of Saginaw County is downwind from the Shiawassee and Titibawassee Rivers, and a national game area south of Saginaw City, all with a lot of buckthorn.

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Christy Sprague...Postemergence herbicide applications for weed control in soybeans are quickly approaching. The hot weather has both weeds and soybeans actively growing. With these approaching applications, there are several things that should be considered to maximize weed control with glyphosate in Roundup Ready soybeans. Following these guidelines can help reduce the risk of glyphosate failures, as well as reduce the chances of lower soybean yields due to weed competition.

[Read the rest of this article...]

Christy Sprague...Early season weed competition may be one of the biggest contributors to unseen yield losses in soybean. Appropriately timing postemergence herbicide applications is critical to preserving crop yields. Several studies have shown that delaying postemergence weed control strategies can substantially reduce crop yield. This has become more of a concern with the large number of glyphosate-resistant crop acres that rely on postemergence applications of glyphosate for weed control.

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Christina DiFonzo...Aphid suction traps have been running in Michigan for the last several weeks. Last week, winged soybean aphids were captured in traps at the Kellogg Biological Station in Kalamazoo County and at the MSUE office in Monroe County. This is the first time winged soybean aphids were found in a suction trap before mid-summer flights in July. The suction trap network is running a bit earlier this year, which may explain why we are able to detect spring flight.

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Diane Brown-Rytlewski...Although scouting for soybean rust hasn’t started in Michigan yet, as our soybeans are still being planted, it is taking place in sentinel plots in states further south. There have been no new detections of rust reported in over 10 days. According to the report at the www.sbrusa.net site, soybean rust was last detected in a kudzu patch west of New Orleans in New Iberia, Louisiana.

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Diane Brown-Rytlewski...Recent heavy rainfalls have delayed soybean planting, and put more pressure on growers to plant when conditions are less than ideal, but it’s a good idea to consider the effect of planting into wet soils on soybean seeds from a perspective of seed and seedling diseases.

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Christy Sprague...Timely burndown herbicide applications in no-till fields are extremely important in protecting soybean yield. As no-till drills start planting soybeans, remember the importance of a timely burndown application. The tendency for a number of growers, particularly those planting Roundup Ready soybean, will be to plant into a weedy mess and not worry about applying their burndown herbicide until later, or to wait until most of the summer annual weeds have emerged before making their first post-emergence glyphosate application.

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Christina DiFonzo...There is good news and bad news related to soybean aphids...Entomologists from Illinois, Indiana, Ontario, Ohio and Michigan all report having a surprisingly difficult time finding soybean aphids on buckthorn, given the number of eggs this winter. It appears that the cold weather did reduce populations on exposed trees.

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Diane Brown-Rytlewski...Previously available only for soybean rust under a special Section 18 emergency use label, Domark (Valent USA Corporation) has received a new label (Section 3) allowing use on soybeans for soybean rust (as both a preventative and a curative), and a number of other soybean diseases.

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Diane Brown-Rytlewski...You’ve probably read about the soybean rust found in early March on soybean residue from a bin of soybeans produced in Iowa in 2006, but if you haven’t you can read about it at the link listed here: http://www.plantpath.iastate.edu/soybeanrust/node/394 . Even though it’s early in the season, I thought that I’d start giving you some updates on what is happening with soybean rust so far this year further south.

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Kurt Thelen...Recent research conducted in the North Central Corn Belt suggests that soybean planting populations may be able to be dialed back somewhat without compromising yield, or more importantly, profitability. Research conducted throughout the Midwest is showing that a final harvest population of 100,000 plants per acre is generally sufficient to achieve maximum yield.

[Read the rest of this article...]

Christy Sprague...The use of postemergence (POST) glyphosate in Roundup Ready soybeans has been the primary weed control program used by many Michigan soybean growers. While this system has seemed to simplify weed management, relying on total postemergence herbicide programs can be difficult to manage if not properly implemented. The flexibility in application timing that glyphosate offers may make it easier to control larger weeds, however the benefits of early-season weed control to protect crop yield can be lost if applications are not made in a timely manner.

[Read the rest of this article...]

David Hillger and Christy Sprague...Since the release of the 2007 Weed Control Guide for Field Crops, several new herbicides have been registered for the 2007 growing season in corn and soybean.  Following is information on some of the new products you will hear about this season.  New registrations or label changes that occurred prior to publishing the Weed Control Guide can be found in the previous article, Updates from 2007 Weed Control Guide for Field Crop.

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Mike Staton...The Soybean 2010 website has been updated to include new soybean management information aimed at helping Michigan soybean producers increase soybean yields and farm profitability. The site can be found at: http://web1.msue.msu.edu/soybean2010/. Nine, new soybean fact sheets covering key management topics were developed in 2007 and are posted on the Soybean 2010 website.

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Kurt Thelen and Terry Shulz...Nitrogen fixation is a result of the symbiotic relationship of Rhizobia bacteria and soybean plants. These bacteria fix atmospheric N2 into the NH4 form, which is useful to the plant. In return, the plant provides the bacteria with carbon photosynthesis products (dicarboxylic acids), which the bacteria use as food. Establishing rhizobia or inoculation in a field that has never grown soybean is needed to ensure nitrogen fixation. Elmore (1996) suggests when and how soybeans should be inoculated, and provides recommendations on inoculate type to use.

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Christina DiFonzo...Based on egg sampling this week at MSU, soybean aphid eggs made it through the winter, and they will hatch as buckthorn buds break in the next few weeks. Over the past four years, soybean aphid nymphs were found by mid-April in mid-Michigan, so egg hatch likely occurs in late March or early April in southern and central counties.

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Christina DiFonzo...This issue of the Field Crop CAT Alert includes an article by Terry Schulz and Kurt Thelen about seed treatments and soybean yield response. From a soybean aphid standpoint, I can confirm many of their findings.

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Terry Schulz, Kurt Thelen and Chris Difonzo...Two neonicotinoid seed treatments have been registered for use on soybean since 2004: Cruiser, (thiamethoxam, Syngenta Crop Protection) and Gaucho (imidacloprid, Bayer Crop Science). This class of insecticide has chemical qualities amenable for use as a seed treatment including a relatively high water solubility and reduced toxicity to humans and animals. Manufacturers of these seed treatments claim these products provide early season protection against several different insect pests, as well as contribute to the overall health of the plant.

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Fred Warner...Soybean is host to many types of plant-parasitic nematodes. Obviously, the nematode that demands the most attention is the soybean cyst (SCN). SCN is a major limiting factor in the production of soybeans worldwide and is estimated to cost U.S. soybean producers over 1 billion dollars annually. However, because of its importance, other nematodes are often ignored.

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Diane Brown-Rytlewski...For many parts of the state, soybeans are at the stage of development (R4-R6) when symptoms of sudden death syndrome (caused by the fungus Fusarium solani f.sp. glycines) start to appear in infected soybeans. Early symptoms include small, round, light green to yellow spots on leaves between the veins. Later, the areas between the veins turn brown to tan with chlorotic margins, while the veins remain green.

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Diane Brown-Rytlewski...Soybean canopies have grown very lush from the recent hot weather and rain.  Now that the weather has cooled off, particularly if you are in the areas that received heavy rainfall, be on the lookout for white mold. White mold is caused by the fungus Sclerotinia sclerotiorum. Cool temperatures (less than 85°F), rainy weather, moist soil and high humidity in the crop canopy, particularly as plants are flowering provide a favorable environment for the disease.

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Diane Brown-Rytlewski...On July 26, soybean rust was confirmed on soybeans from a sentinel plot in Rapides Parish, Louisiana. This is the first report of rust on soybeans in Louisiana for the 2006 season. So far this year, rust has been confirmed on soybeans in six different counties in four states: Alabama, Florida, Georgia and Louisiana. The rest of the finds have been on Kudzu – 26 counties in five states: Alabama (5), Florida (12), Georgia (5), Louisiana (3) and Texas (1).

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George Rehm with Ron Gehl...This time of the year we often receive questions regarding foliar fertilization of row crops. Past research has shown that nutrient deficiencies can sometimes be corrected with foliar applications, resulting in a positive yield response. But in areas where there are no obvious deficiencies, can foliar nutrient applications increase crop yields? Results of nationwide studies have shown mixed results. Even where yield increases have been observed, the level of yield increase often does not offset the cost of the fertilizer and application.

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Christy Sprague...Recently, Monsanto has clarified the maximum stage for which glyphosate can be applied to Roundup Ready (glyphosate-resistant) soybeans. Currently stated on glyphosate labels, glyphosate can be applied from soybean cracking to “throughout flowering”. Throughout flowering is defined as the R2 soybean growth stage. The R2 soybean growth stage is where one of the two uppermost nodes on the main stem has an open flower. The R3 growth stage starts when one of the four uppermost nodes with a fully developed trifoliate leaf on the main stem has a pod that is 3/16 inches long.

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Diane Brown-Rytlewski...Despite recent dry weather, growers may still be seeing evidence of root rot diseases in soybean fields, especially those that were very wet earlier in the year. Pythium root rot and Phytophthora root rot can develop in poorly-drained or saturated soils or soil that suffers from compaction. No-till areas with fine-textured soils tend to be favorable environments for these diseases, as the soil can become more easily saturated than coarser textured soils.

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Diane Brown-Rytlewski...Today’s Field Crop CAT Alert contains a pdf on scouting for soybean rust. The second page contains color drawings of soybean R (reproductive) stages. The scouting period for rust begins at R1, when soybeans have at least one open flower at any node, and ends once soybeans reach full seed (R6). Risk levels for soybean rust in Michigan remain very low.

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Jan Byrne, Joe Svoboda and  James Taulbee...There were 8 samples received from sentinel plots during the reporting week of June 21-28, 2006. The following is a compilation of the reports.

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Diane Brown-Rytlewski...Soybean rust has been found on soybeans in southern Florida. The impacts of tropical storm Alberto on the spread of rust haven’t shown up yet, but sentinel plots are being watched closely.

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Diane Brown-Rytlewski...Scouting in Michigan sentinel plots has started, but is off to a slow start due to the weather. Soybeans are still fairly small. No rust has been detected...Further south, soybean rust is still being found on kudzu in Florida, and was found on kudzu in Georgia yesterday. There have been no finds on soybean yet in either location. Soybeans are at early bloom (R1-R2) in Florida.

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Diane Brown-Rytlewski and Willie Kirk...An updated fact sheet on where to get information about soybean rust forecasts, models and information can be found at: http://www.ipm.msu.edu/cat06field/pdf/6-8sbrinfo.pdf

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Christina DiFonzo...And to follow up on the previous article about suction traps, here is the latest update on soybean aphid in soybean.  Dave Ragsdale from the University of Minnesota reports that soybean aphid was found in multiple locations throughout Minnesota on V1 soybeans. The earliest find was in mid-May on volunteer beans along the Minnesota River in south-central Minnesota.

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Christina DiFonzo...Northcentral Regional Aphid Suction Trap Network was turned on last week in at least eight states. As in 2005, Michigan has three trapping locations that cover a north-south transect:  MSU’s Saginaw Valley Bean and Beet Research Farm in Saginaw County; the MSU Entomology Farm in Ingham County; and the Kellogg Biological Station in Kalamazoo County.

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Christina DiFonzo...The pictures accompanying this article show the feeding caused by tiny globular springtails on soybean cotyledons. (see photos) Springtails are common beneficial insects that eat decaying plant material, fungi or bacteria, breaking down residue and improving soil structure. Springtails are very common in fields with high residue and moist conditions. They sometimes move onto living plant material and feed, leaving a scraped or scarred appearance on cotyledons.

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Christina DiFonzo...A few weeks ago I reported that entomologists from Purdue and Illinois found only two aphid colonies in their annual buckthorn survey. Both colonies were found near Bronson, Michigan. (see photos) This week I hit the jackpot and found 22 colonies on a single buckthorn shrub on the MSU campus. Although there are dozens of other buckthorn shrubs in the area, none of the others had aphid colonies.

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Christina DiFonzo...Many of you are aware of the soybean rust web site (http://www.sbrusa.net/) sponsored by USDA last year. That site provides a map that shows soybean rust detections in sentinel plots and on kudzu, an alternate rust host. There is also commentary provided by state specialists. Knowing the progression of the disease north will help producers target scouting and apply preventative fungicide applications.

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Christina DiFonzo...Syngenta just announced a reduction in the pre-harvest interval (PHI) for Warrior w/ Zeon Technology on soybeans only. The new PHI is 30 days, compared to 45 days. This change is particularly important for soybean aphid control. The recommended rates remain the same:

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Diane Brown-Rytlewski and Willie Kirk...Last year it was too cold, and this year it’s been too dry. Until recently, weather in the Southern states has been hot and dry, so soybean rust is off to a slow start again. No new soybean rust has been found in Georgia despite recent rainfall and favorable temperatures. Similarly, there has been no rust found in Louisiana. Soybean rust has been found in northern Florida on kudzu and on kudzu in the southeastern corner of Alabama.

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Kurt Thelen...The heavy rains have continued and have resulted in isolated areas of severe ponding in parts of the state. This problem has left growers struggling with the question of whether or not to replant water damaged stands and how to manage fields that have yet to be planted.

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Christina DiFonzo...In the first week of May, Dave Voegtlin from the Illinois Natural History Survey and Bob O’Neil from Purdue spent four days (1,300 miles) in Indiana, Ohio and Michigan looking for soybean aphid on buckthorn. Recall that buckthorn is the overwintering host for soybean aphid (SBA). Dave and Bob examined two known buckthorn hosts (Rhamnus alnifolia & R. cathartica) as well as “suspected” hosts (R. frangula and R. caroliniana).

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Kurt Thelen and Terry Schulz...Seed treatment insecticides such as Cruiser and Gaucho have been marketed for early season soybean aphid and bean leaf beetle control. Results from two years of performance trials conducted in Michigan indicate that soybean yield response to these seed-applied insecticides depends primarily upon the aphid pressure experienced during the early growing season.

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Christy Sprague...Even with the substantial number of Roundup Ready soybean acres in the state this year there are several producers that will be growing non-GMO soybeans. Since some of these producers haven’t planted non-Roundup Ready soybeans for several years, there are few pointers that should be remembered for effective weed control in conventional (non-GMO) soybeans.

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Christy Sprague...Timely burndown herbicide applications in no-till fields are extremely important in protecting soybean yield. Within the next two weeks soybean planting will be in full-force. As several no-till drills start planting fields, remember the importance of a timely burndown application. The tendency for a number of growers, particularly those planting Roundup Ready soybean, will be to plant into a weedy mess and not worry about applying their burndown herbicide until later or to wait until most of the summer annual weeds have emerged before making their first postemergence glyphosate application.

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Mike Staton...There is an increasing interest in planting soybeans early. This article summarizes the risks and benefits of early planting. Specific management practices for early planted soybeans are also provided. One of the biggest advantages of early planting is that it provides a longer planting window for attaining maximum yields. Data from the University of Wisconsin and The Ohio State University indicate that beans planted on May 1 will yield about seven bushels per acre higher than beans planted during the last week of May.

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Christy Sprague...The use of postemergence (POST) glyphosate in Roundup Ready soybeans has been the primary weed control program used by many Michigan soybean growers. While this system has seemed to simplify weed management, relying on total postemergence herbicide programs can be difficult to manage if not properly implemented. The flexibility in application timing that glyphosate offers may make it easier to control larger weeds, however the benefits of early-season weed control to protect crop yield can be lost if applications are not made in a timely manner.

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Jim Kells and Kathrin Schirmacher...There are currently a large number of winter annual and perennial weeds present in no-till corn and soybean fields. It is important to control these weeds prior to crop emergence. These weeds may become very competitive if not controlled.

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Christina DiFonzo...There are now two new seed treatments registered for soybean. Cruiser (thiamethoxam) was available in 2005; Gaucho (imidacloprid) can be used in 2006. Soybean seed can be ordered already treated, or treated by a commercial outfit after purchase. In most cases, insecticide-treated seed will also be fungicide-treated. The prices we were recently quoted for Cruiser and Gaucho treated seed were between $9 and $12 per unit (50 lb bag) = $10 to $14 per acre.

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Christina DiFonzo...General lessons from many trials in 2005
§      Scouting pays: Soybean aphid (SBA) problems were detected early by scouting and variability in infestation (and need for treatment) was also noted.
§      Residuals differ: OPs tend to have better initial kill but shorter residual. Pyrethroids tend to have longer residual.
§      Yields often don’t differ: In the end, however, yield generally depends more on spraying itself, then on choice of insecticide.
§      Coverage counts: Coverage probably explains many of the performance problems with various insecticides.
§      Tank mixing: Tank mixes of pyrethroids with Lorsban did not improve yield.
§      Reduced rates: Reduced rates of insecticides did not provide adequate control or improve yield.

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Diane Brown-Rytlewski...Last year, a series of fact sheets about soybean rust were developed. Those fact sheets have undergone major revisions to provide additional information that has been requested. Fungicide Application Technology for Soybean Rust-2006 is avaiable as a pdf at: http://www.ipm.msu.edu/cat06field/pdf/sbr_aptechnology.pdf

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Diane Brown-Rytlewski...Last year, the national sentinel plot system worked very well to track the spread of soybean rust in the United States. This year, there will again be a national sentinel plot network, with a higher proportion of plots in the southern states, where soybean rust is found early in the season.

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