March 22, 2007

In this issue

§      Time to spring into 2007

§      Neonicotinoid seed treatments for soybeans

§      Seed treatments and soybean aphids

§      Soybean aphid update and sources of information

§      Outlook for Stewart’s disease for 2007

§      Corn nitrogen recommendation systems

§      MSU corn N research update

§      Continuous corn cautions

§      Early spring assessment of wheat to estimate yield potential

§      Winter wheat response to nitrogen

§      New seeding of Roundup Ready alfalfa halted

§      Farm sprayer “tune up”

§      Enviro-weather is geared-up for the 2007 growing season

§      Water use reporting for 2006 irrigation

§      Southwest Regional Report

§      Weather news

Time to spring into 2007

The farmers in my neighborhood were starting up field work this week before the warm rains hit – spring is here. Today’s issue is packed with advice for your consideration as you plan your crop and pest management for 2007. We also invite you to use the Internet and search the last five seasons of the Field Crop CAT Alerts for specific topics at: http://www.ipm.msu.edu/fieldsearch.htm

With this issue we say good-bye to assistant editor Rebecca Lamb. She has been a reliable and capable hand in production of this newsletter, and we will miss her contributions here at IPM Communications. Rebecca has been part of our team for six years and is leaving for new challenges as a graphic artist for a Michigan organization. Our best wishes go to Rebecca on her new career.

Next issue – April 12

If you have suggestions for our newsletters, please feel free to contact me at (517) 353-4951 or catalert@msu.edu. Internet readers can also sign up to receive a brief email when we post new issues on the Internet. See this site for details: http://ipm.msu.edu/email-field.htm – Joy Landis, editor.

Neonicotinoid seed treatments for soybeans

Terry Schulz and Kurt Thelen, Crop and Soil Sciences
Chris Difonzo, Entomology

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. Advertised plant health benefits include greater stands, plant height and root, stem and leaf development.

At Michigan State University we conducted field and greenhouse research to evaluate soybean yield response and alleged plant health benefits of these seed treatment products. Studies were performed at a total of 14 sites between 2004 and 2006. Both thiamethoxam and imidacloprid insecticides were also tested in tandem with Apron Maxx fungicide. (View chart)

For the duration of the study, thiamethoxam and imidacloprid treatments were used in a total of 168 plots each. Harvest yields were taken, along with plant stands and early plant height at each site. Chlorophyll indices, harvest plant height and pods per plant samples were taken at two sites each year. Finally, periodic aphid population counts were taken at two sites during the 2005 growing season as aphid pressure increased in July and August.

Use of neonicotinoid seed treatments resulted in significant soybean yield increases at three of 14 site-years during the study. Thiamethoxam provided a 5.0 bu./acre yield increase at Ingham in 2004. However, no other sites in 2004 or in 2006 saw a significant yield increase due to insecticidal seed treatment. Two of the four site years saw significant yield increases during 2005, when soybean aphid pressure was extremely high. Thiamethoxam and imidacloprid had early season efficacy on soybean aphid. Thiamethoxam and imidacloprid provided a 5.7 and 7.7 bu./acre advantage at Hillsdale in 2005, and a 12.7 and 9.0 bu./acre advantage at Sanilac in 2005.

The Hillsdale site had no foliar insecticide application, while the Sanilac site had an application made to all treatments well beyond when soybean aphid had reached threshold, to allow the seed treatment to exhibit its effectiveness. However, a well-timed foliar insecticide application is more effective at protecting soybean grain yield than seed treatments when aphid pressure is high.

Aphid population count data in 2005 revealed that soybean aphid populations were suppressed through R2, but significant population differences were not observed after R2. This corroborates the observation by Pedersen and Lang that soybean seed treatments can be expected to provide some level of aphid suppression up to 60 days after planting. Late R2 was approximately 57 and 69 days after planting at the two sites where counts were taken. However, one must remember that soybean aphid arrived extremely early in 2005, and the effectiveness of these treatments on soybean aphid will depend on soybean planting date and on how early aphid pressure occurs. Early planted soybean may not see the level of aphid control that a late planted soybean would see as a result of neonicotinoid seed treatments.

Plant vigor effects were not observed on a wide-spread basis in this trial. Slight and isolated plant height effects were observed, and no leaf chlorophyll or pod count effects were observed. One site saw a significant increase in stand count from neonicotinoid treated soybean, and this was a site which was planted relatively early in 2004 (April 30), with near record rainfall following the planting. A Minnesota study found an advantage in seedling emergence from neonicotinoid seed treatment in early planted soybean, but not in soybean planted three weeks later.

In conclusion, neonicotinoid seed treatments did not appear to improve crop health or provide widespread significant soybean yield increases in the absence of soybean aphid. However, these trials were performed in a conventional tillage system without early season insect pressure from bean leaf beetle (Certoma trifurcata). Expected bean leaf beetle and other insect pressure should be considered when deciding whether to use these seed applied insecticides. These treatments may perform better in a no-till system, where increased crop residue may lead to increased insect pressure. Thiamethoxam and imidacloprid can provide soybean aphid suppression through R2, but will not hold soybean aphid under threshold for an entire growing season if pressure is near levels experienced in 2005.

References:

Pedersen, P. and B. Lang. 2006. Use of insecticide seed treatments for managing soybean aphids. Integrated Crop Management Newsletter, Iowa State University Extension. Issue IC-496(1):39-40.

Potter, B. 2003. Seed applied insecticide control of the soybean aphid (Aphis glycines) and bean beetle (Cerotoma trifurcata). University of Minnesota Southwest Research and Outreach Center (Online). Retrieved Nov 8, 2006 from http://swroc.coafes.umn.edu/SWMNPEST/swmnpest.htm

Seed treatments and soybean aphids

Christina DiFonzo
Entomology

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.

Neonicotinoid seed treatments are recommended in soybean fields with a history of economic damage from seed corn maggot, white grubs and other soil insects. Bean leaf beetle is another early season pest that is controlled by seed treatments. In Michigan, early-season populations of bean leaf beetle are rarely high enough to merit treatment (Young beans can tolerate considerable injury.), but in western states where beetle populations are typically higher, seed treatments may be valuable. However, there is no good evidence that bean pod mottle virus infection (transmitted by bean leaf beetle) is less in seed-treated soybean.

Seed treatments for “insurance” or prophylactic control of soybean aphid are not recommended as a standard practice. Laboratory and field studies indicate that soybean aphid begins to survive on seed-treated plants 35 to 40 days after planting. In many parts of the United States and Canada, this is just when aphids begin to colonize fields. In outbreak years, populations in seed-treated fields often reach the 250 threshold, and require foliar insecticide sprays, at the same time as in untreated fields. Replicated university research trials across multiple states and years do not show a significant yield increases from using seed treatments under no or low aphid pressure. Many of these trials used small plots, but others were done in 1-acre blocks (Michigan, Iowa and Minnesota) or in replicated strips the length of a field (Nebraska). During aphid outbreaks, using an IPM approach based on crop scouting and thresholds to optimally-time a foliar spray results in significantly greater yield compared to using a seed treatment. An IPM approach to soybean aphid control also limits insecticide use to when and where it is needed, reducing pesticide exposure and selection for resistance. Formation of insecticide resistance is a growing concern, because neonicotinoids are available as both seed treatments and foliar sprays in many crops.

In Michigan, there is one small area where I believe past history may justify a seed treatment for soybean aphid in predicted outbreak years. Parts of Monroe County in southeast Michigan have some of the heaviest infestations of buckthorn (soybean aphid’s overwintering host) in the state. In the spring of 2005, colonization of soybean fields around Dundee, Monroe and other towns near the River Raisin was early and heavy, and aphids went over threshold by mid-June. Some fields were sprayed early, while other fields had been seed treated. In essence, the seed treatment replaced the first foliar spray. Later, fields were reinfested and many were sprayed a second time in late July. Remember, this is an exceptional area, based on the sheer amount of buckthorn. We know egg numbers were very high in this area this past fall and aphids may colonize fields early. Again, in this limited area of Michigan, the assumption is that early colonization sets up a two-spray system, and a seed treatment replaces the first foliar spray. From a time management standpoint, I realize that the seed treatment has advantages on the farm. From an IPM standpoint, though, two foliar sprays are equally as effective, and the sprays can be timed if and when they are needed.

Soybean aphid update and sources of information

Christina DiFonzo
Entomology

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.

Michigan will participate again in two publicly available aphid-sampling programs

The traps in the Northcentral region aphid suction trap network will begin the first week of June. Results of the suction trapping are reported each week at http://www.ncpmc.org/traps/index.cfm.

Michigan has suction traps in Kalamazoo, Monroe, Ingham, Saginaw and Oceana counties. In 2006, no soybean aphids were caught in suction traps until late July. Thereafter, a total of only eight soybean aphid were captured in the five traps through August. This compares to 4,440 soybean aphid caught in a single week at a single location in August 2005, during the last outbreak. Soybean aphid numbers increased in suction traps in southern and central Michigan last fall, especially in Monroe County. In October, numerous oviparae and eggs were found on buckthorn at multiple locations. Based on the suction trap catches and egg numbers, we predict an aphid outbreak in 2007. During the 2007 field season, large flights of winged aphids will indicate the potential for virus transmission in vegetable crops. This could help growers choose resistant varieties for later plantings, or time harvests of certain crops. In September and October 2007, the suction traps will help us predict aphid populations in 2008.

Aphid numbers in the field will be reported on the USDA’s PIPE website, also know as the “soybean rust map.” That website is http://www.sbrusa.net/.

In the upper right corner of the web page, under today’s date, there is a drop box to switch the site view from rust maps to aphid maps. Note that when a state appears in color, a commentary is available about aphid numbers. During the field season, I will update the map with aphid numbers from the sites we sample weekly, and include reports of aphid populations from Extension educators and agribusiness contacts.

Outlook for Stewart’s disease for 2007

Diane Brown-Rytlewski, Plant Pathology
Beth Bishop, Entomology
Tracy Aichele, Enviro-weather

Growers of sweet corn and seed corn are well acquainted with Stewart’s disease (Stewart’s wilt), a bacterial disease transmitted to corn in spring by corn flea beetles carrying the disease feeding on emerging corn seedlings. Corn flea beetles survive over winter in grassy areas, in soil and plant debris, and become active in the spring once temperatures warm to around 65-70ºF There are several generations of corn flea beetles per year. Some sweet corn and seed corn hybrids are susceptible to Stewart’s wilt, and management includes (in order of preference) the use of resistant hybrids, insecticidal seed treatments (Cruiser or Poncho), soil insecticides and foliar insecticide to control the beetle. There are no treatments aimed at controlling the bacterium, Pantoea stewartii, that causes the disease; you control the beetles that carry the bacterium. The disease is not transmitted plant-to-plant. It spreads with the assistance of corn flea beetles carrying the bacterium and depositing it with their feces into wounds created as they feed on the corn foliage.

For field corn, the primary means of managing this disease is through the use of resistant hybrids. In looking through seed catalogs, there seem to be fewer earlier maturing field corn hybrids that list resistance to Stewart’s disease among their characteristics than later maturing hybrids. Resistance limits the movement of the bacterium in the vascular system and keeps the plants from becoming systemically infected.

An outbreak of Stewart’s disease was reported on field corn hybrids in a number of locations last August and September of 2006. But we do not know if Stewart’s wilt infection affects the yield of field corn: We are not aware of any studies that show yield is affected. We do not know whether or not the disease will show up in field corn this spring. Plant pathologists from other states with a history of Stewart’s disease on field corn report that it generally appears as a foliar blight, later in the season, rather than in the wilt phase on seedlings. Most field corn is thought to have some resistance to the seedling wilt phase of the disease, and if the disease shows up, it occurs later in the season (after flowering), although that isn’t always so.

Although a number of fields showed symptoms of the disease, we do not have comparative research data that tells us whether the late season Stewart’s disease resulted in yield losses. Similarly, we do not know how many of the flea beetles carrying the disease survived over the winter. Corn fields bordering woodlots or protected areas that would shelter beetles from extreme weather may have higher survival of flea beetles. There are no “rescue treatments” or applications recommended for the leaf blight phase that shows up in late summer.

However, we do know that mild winter temperatures were favorable for beetle survival in much of the state. If Stewart’s disease was a problem in your area last year, the winter probably didn’t have much effect on killing the beetles. The average monthly air and soil temperatures for December, January and February were calculated for the Lower Peninsula MAWN (Michigan Agricultural Weather Network) weather station locations. Predictions for Stewart’s disease risk in Michigan for spring, 2007 is based on two models as shown in the accompanying table.

A paper published in Plant Disease, (October 2006, pp. 1353-1357) compared the accuracy of the models used to predict the prevalence of Stewart’s disease based on winter air temperatures during December - February. The Stevens-Boewe model predicts the risk of the late leaf blight phase of Stewart’s disease. At most of the locations in the table, the Stevens-Boewe model indicates a low (trace) risk of the foliar blight phase of the disease. This model tends to under predict the risk of Stewart’s disease.

Although it works well in some cases, with heavy snow cover, hedgerows or woods bordering a field, beetles may survive in higher numbers than the model would predict. The Iowa State model, which was developed for seed corn, hasn’t been tested in Michigan. It uses the number of months (0-3) during December - February that the average monthly air temperature exceeded 24ºF. Most of the locations in the table reflect a moderate level of risk for Stewart’s disease this spring. The coldest month was February, but even with air temperatures mostly in the teens, we had good snow cover to act as insulation in many locations.

We may have higher than normal survival of corn flea beetle and more Stewart’s disease, but we still don’t know if it will affect yield in field corn. Any management method will have an associated cost. Growers will need to assess the cost/risk benefit to determine their course of action. Seed corn and sweet corn growers growing susceptible hybrids should be prepared to scout their fields when plants begin to emerge in spring and take appropriate measures. To recap, the four methods of managing Stewart’s disease are: planting resistant hybrids (best), using Poncho or Cruiser seed treatments (effective for 35 to 40 days), soil insecticides and foliar treatments. Keep in mind that rapid plant growth, weathering, and an influx of new beetles limit the effectiveness of foliar insecticides. The economic treatment thresholds, prior to stage V5 in seed corn are 10 percent of the plants with severe feeding injury and two or more beetles per plant, and in commercial hybrid corn, 50 percent of plants with severe feeding injury and five or more beetles per plant.

Table 1

Comparison of forecasting models for Stewart’s Disease (Wilt), and survival potential of corn flea beetles.

*Stevens-Boewe model to predict risk of Stewart’s Wilt-late leaf blight phase- Sum of mean monthly air temperatures for December, January and February : < 80ºF =trace; 80-85ºF=light, 85-90ºF= moderate; >90ºF= severe

** Iowa State Model- to predict risk of Stewart’s disease- number of months (0-3) where mean monthly air temperature was above 24ºF (December, January and February) 0=negligible, 1 = low, 2= moderate/high, 3=high.

MAWN Station

Town

Stevens Boewe Model * avg. monthly temps

Dec+ Jan +Feb/3

Iowa State

Model** months w/ avg. monthly air temp > 24F (0-3)

Albion

Albion

75.9

Trace

Moderate/high

2

Bainbridge

Watervliet

82.9

Light

Moderate/high

2

Bath

Laingsburg

73.6

Trace

Moderate/high

2

Bear Lake

Bear Lake

76.3

Trace

Moderate/high

2

Belding

Belding

74

Trace

Moderate/high

2

Benzonia

Benzonia

77.6

Trace

Moderate/high

2

Ceresco

Ceresco

78.1

Trace

Moderate/high

2

Clarksville

Clarksville

74.3

Trace

Moderate/high

2

Commerce

Commerce Township

76

Trace

Moderate/high

2

Constantine

Constantine

78.9

Trace

Moderate/high

2

East Leland

Suttons Bay

74.5

Trace

Moderate/high

2

Eastport

Eastport

75.8

Trace

Moderate/high

2

Elk Rapids

Elk Rapids

74.9

Trace

Moderate/high

2

Entrican

Lakeview

72

Trace

Moderate/high

2

Fairgrove

Fairgrove

72.8

Trace

Moderate/high

2

Fennville

Fennville

82.9

Light

Moderate/high

2

Freeland

Freeland

74.1

Trace

Moderate/high

2

Fremont

Fremont

76.5

Trace

Moderate/high

2

Grand Junction

Grand Junction

85.3

Moderate

Moderate/high

2

Hart

Hart

77.9

Trace

Moderate/high

2

Hartford

Hartford

80.6

Light

Moderate/high

2

Hawks

Hawks

65.5

Trace

Low

1

Hudson

Clayton

73.5

Trace

Moderate/high

2

Hudsonville

Hudsonville

81

Light

Moderate/high

2

Ithaca

Ithaca

71.9

Trace

Moderate/high

2

Kewadin

Kewadin

78.1

Trace

Moderate/high

2

Lapeer

Lapeer

73.6

Trace

Moderate/high

2

Lawton

Lawton

84.3

Light

Moderate/high

2

Linwood

Kawkawlin

71.7

Trace

Moderate/high

2

Ludington

Ludington

80.7

Light

Moderate/high

2

Mendon

Mendon

78.4

Trace

Moderate/high

2

MSU Hort

East Lansing

76.3

Trace

Moderate/high

2

Munger

Munger

79.3

Trace

Moderate/high

2

Northport

Northport

78.3

Trace

Moderate/high

2

NWMHRS

Traverse City

74.6

Trace

Moderate/high

2

Old Mission

Old Mission

60.1

Trace

Low

1

Petersburg

Dundee

78

Trace

Moderate/high

2

Pigeon

Pigeon

72.8

Trace

Moderate/high

2

Saginaw

Saginaw

72.6

Trace

Moderate/high

2

Sandusky

Sandusky

74

Trace

Moderate/high

2

Scottdale

St. Joseph

88.9

Moderate

Moderate/high

2

South Haven

South Haven

87.7

Moderate

Moderate/high

2

Sparta

Sparta

76.5

Trace

Moderate/high

2

SWMREC

Benton Harbor

83.6

Light

Moderate/high

2

West Olive

West Olive

82.5

Light

Moderate/high

2

Corn nitrogen recommendation systems

Ron Gehl
Crop & Soil Sciences

Questions have started coming in as late regarding N management for corn this year. While corn prices are high relative to this time last year, the recent increases in N fertilizer prices will add significant costs to production. Costs for urea and UAN have climbed to equivalents of over $0.50 per pound of actual N, so implementing efficient N management practices will be key again this year for maximizing economic returns. Obviously, N rate decisions are going to be a principal factor in optimizing returns, and there has been much discussion and informational publication regarding N rates and changes to N recommendation systems throughout the North Central Region. With corn planting right around the corner, I wanted to take an opportunity to explain some of the differences in N recommendation strategies and discuss our current Tri-State N recommendations for corn.

So, why have we seen all the recent changes to N recommendations for many states in the Corn Belt? The answer is not necessarily a simple one, and is a result of many factors, but ultimately comes down to achieving the goal of maximizing economic return to N fertilizer invested with due attention to negative environmental consequences often associated with excessive N rates. Until very recently, most universities/states in the Corn Belt recommended N rates heavily based on an anticipated yield goal for a given field. The yield goal recommendation strategy used for the past 30+ years primarily evolved from a paper published by ARS soil scientist George Stanford in 1973. Stanford described a mass balance approach, using N uptake by the crop with N supplied by non-fertilizer sources and fertilizer efficiency, for determining N fertilizer needs. The work by Stanford identified a corn N requirement on a per-unit of yield basis (about 1.2 lb N per bushel), as an approach that became widely adopted for formulating yield goal based N recommendations. Modifications to the approach varied from state-to-state, with adjustments for factors such as residual N, previous crop, manure, soil organic matter, etc. The yield goal approach for formulating N recommendations received increasing scrutiny in many states in recent years, due to factors including:

§      Poor relationships identified by researchers between recommendations and the economic optimum N rate (EONR) observed in trials.

§      Poor relationships between optimum N rates and grain yield achieved at those N rates (high corn yield levels achieved with relatively low N fertilizer inputs, or vice versa).

§      Inconsistencies and uncertainty as to the appropriate estimation of yield goals.

§      The assumption of a constant N use efficiency among sites and years.

§      Uncertainty of the appropriate adjustments for non-fertilizer N.

As an alternative to yield goal-based recommendations, many researchers proposed using a system based on economic return to N inputs, specifically identifying an economic optimum N rate. Corn response to N fertilizer typically follows the basic principle of diminishing returns – where yield response to applied N becomes less for each subsequent increment of N fertilizer added (on a responsive site, you can expect a greater yield response for the first 10 lbs of N added compared with the next 10 lbs, etc.). The EONR is the point where the last increment of N added returns a yield increase large enough to pay for that N. The EONR is not a static measurement, and will vary some depending on the value of corn grain and the cost of N fertilizer. An approach similar to the EONR, with slight modifications, was adopted by several states (Iowa, Illinois, Minnesota and Wisconsin) in the North Central Region last year. This approach uses response trial data from each state to determine a maximum return to N (MRTN) for that state’s dataset. (It’s important to recognize that each state has its own recommendation using this approach, based on data collected specifically from that state, but that all follow the same approach for determining N recommendations.) The MRTN is the N fertilizer rate where economic net return to N application is greatest (Sawyer et al., 2006). With the MRTN, N rates with net return within $1.00/acre of the MRTN provide a range of N rates with similar profitability, and allows growers some flexibility in determining the appropriate N rate for a given field. Specifics of the MRTN approach, as well as rationale for the approach can be found at:

http://www.extension.iastate.edu/Publications/PM2015.pdf

Currently in Michigan, our N fertilizer recommendation is still formulated using a yield-goal approach, as reported in the Tri-State Fertilizer Recommendations (E2567, http://www.msu.edu/~warncke/E-2567%20Tri-State%20Fertilizer%20Recs.pdf) or the Nutrient Recommendations for Field Crops in Michigan (E2904, http://www.msu.edu/~warncke/E2904%20Nutrient%20Recommendations%20for%20Field%20Crops%20in%20MI.pdf).

Corn (grain) N Rate = (1.36 x YG) – 27 – NC;

Where YG is the anticipated yield goal and NC is N credits from previous crop (30 lb N/ac for soybeans).

Michigan State, as well as our Tri-State colleagues at Purdue and Ohio State, have intentions to modify or improve our current N recommendation based on N rate trial response data collected in recent and upcoming years, and are in discussions as to the most appropriate approach to use for this modification. A series of N rate response trials were initiated throughout Michigan last year, the results of which can be found in the following article by Ron Gehl.

MSU corn N research update

Ron Gehl
Crop & Soil Sciences

The recent increases in N fertilizer costs have driven renewed interest in evaluating producer N management practices for corn. Current Michigan N recommendations for corn are based on response data collected in the 1980’s. Since that time, advancements in corn genetics, insect and weed management and production practices have affected corn yield response to N. Efficient use of N fertilizer for corn production is essential to maximizing economic return for the producer and minimizing adverse effects on groundwater quality and emission of greenhouse gases. Improvement of the Michigan corn N recommendation will require collection of additional N response data due to the lack of this data from recent Michigan research studies. An understanding of the factors affecting corn yield and yield response to N fertilizer in Michigan is important to providing effective N management recommendations over a wide range of soil-climate conditions, maximizing profitability and minimizing negative environmental impacts.

To address this issue, a series of corn N-response trials were initiated for the 2006 growing season. Experimental sites were located in a manner that provided a representation of some of the major soil associations common to Michigan corn production. Treatments consisted of iterations of N fertilizer (urea preplant-incorporated, 28% UAN sidedress injected) from 0 to 200 lb N/ac and were replicated three or four times. Results of ten study locations, including three sites on MSU research farms and seven sites located on producer fields, are shown in Table 1. Results from other recent Michigan N response trials can be found in the April 22, 2004, Field Crop CAT Alert article by Carrie Laboski.

Table 1. Corn yield response to nitrogen fertilizer in 2006.

Location, PC

Max.

Yield

N Rate for Max. Yield

Econ. Opt. N Rate (EONR)

Max. Econ. Yield

 

bu/ac

lb N/ac

lbs N/ac

bu/ac

Branch, Sb

190

148

132

189

Hillsdale, Sb

188

165

145

187

Huron, Sb

218

144

136

217

Ingham,C

199

178

163

198

Ingham, Sb

199

156

141

198

Saginaw, Sb

201

156

144

200

Sanilac, Sb

192

142

130

191

St. Clair, Sb

162

181

143

160

Tuscola, W

187

157

123

185

Van Buren, C

161

151

143

160

PC = Previous Crop, C:Corn, Sb:Soybeans, W:Wheat, clover cover.

Max. Yield = Maximum yield observed at location as determined by quadratic model fit of data.

Econ. Opt. N Rate (EONR) = The economic optimum N rate is the amount of N required for maximum economic yield, as determined by a 10:1 corn to N price ratio ($4.00/bu and $0.40 /lb N), where corn yield is multiplied by corn price and cost of N is subtracted.

Max. Econ. Yield = Maximum economic yield is the corn yield that would have resulted by application of the EONR. Maximum economic yield is often less than the optimum yield due to diminishing returns on fertilizer input (ie. yield response is less for each added increment of fertilizer). As the price ratio narrows, the difference between max. economic yield and max. yield typically becomes larger.

We are currently looking for N trial cooperators for the 2007 growing season. If you are interested in participating in either a strip or small-plot N response trial on your farm, please contact your local Extension educator or:

Dr. Ron Gehl

Michigan State University

Crop & Soil Sciences

580 PSSB

East Lansing, MI 48824-1325

Fax: 517-355-0270

Phone: 517-355-0271 x. 1269

Email: gehlr@msu.edu

Continuous corn cautions

Ned Birkey,
Monroe, Wayne and Washtenaw MSU Extension EANRA

Lots of economic and agronomic factors are affecting Monroe County and area farmers’ decision regarding crop rotation and sequence for 2007 and perhaps into 2008 and even 2009. The corn marketplace has been telling farmers that it needs 10 million more acres, at trend yields, to provide enough supply for projected demand. Higher corn prices, relative to soybeans and wheat, means that farmers are generally going to plant more acres to corn this year.

Issues of corn on corn are not necessarily the same as continuous corn, which implies several years of monocropping. Briefly, here are some issues that farmers who are considering corn on corn and increased corn acreage need to be cognizant of as we enter the all-important spring planting season.

Crop residue issues

The good 2006 corn crop not only meant good yields, but lots of corn residue. One estimate is that 180 bushels of corn has left 10,000 pounds of corn residue. Long term studies at Purdue University have shown a yield “drag” for continuous corn of 3, 5 and 18 percent for moldboard plow, chisel plow and no-till systems respectively.

§      Crop residue harbors greater levels of disease inoculum.

§      Crop residue keeps soils cooler and wetter during or after planting.

§      Crop residue can interfere with planter row units.

§      Crop residue can decrease the efficacy of soil-applied herbicides.

§      Crop residue can keep soils wetter during or after harvest.

Nitrogen fertility issues

§      Most agronomists agree that optimum nitrogen fertilizer rates for corn following corn are higher than for corn following legumes (including soybeans) and range from 30 to 50 pounds of additional N required per acre.

§      Farmers who routinely sidedress most or all of their N fertilizer will require more days to complete this operation. Corn plant height limitations will limit traditional ground sidedress applicator tools.

Phosphorus and potassium fertility issues

§      Corn removes more soil phosphorus and less soil potassium than soybeans.

§      A one-time move to second year corn will have negligible effects on P and K soil fertility levels.

Stand establishment issues

§      High levels of corn residue in continuous corn cropping systems may translate into difficult corn establishment conditions, partly due to slow soil warming and drying of poorly drained soils.

§      High levels of trash can also interfere with furrow opening and closing functions of the corn planter.

§      Not only can germination and emergence be delayed or uneven, but so can initial seedling development. Delayed stand establishment lengthens the potential period of seedling exposure to insects and diseases.

Insect, weed and disease issues

§      Western corn rootworm was prevalent in isolated fields in 2006.

§      European corn borers overwinter in corn residue anyway.

§      Seedling insects such as wireworms, seedcorn maggots, white grubs and slugs may all be problems, particularly in heavy crop residue fields.

§      Gibberella stalk rot is the same host pathogen as head scab in wheat.

§      Gray leaf spot and Northern corn leaf blight are more common in corn following corn.

§      Higher crop residues will “capture” some herbicides. Furthermore, some weed species such as giant ragweed, burcucumber, waterhemp and crabgrass have relatively longer emergence periods, possibly requiring a two pass herbicide program.

Harvest season issues

§      Planting more acres to corn effectively lengthens the corn harvest season because of time and capacity demands on harvest machinery, drying facilities, transportation and storage.

§      Corn on corn means that some fields will be in the field longer and therefore under more standability pressure from insects and stalk diseases.

Early spring assessment of wheat to estimate yield potential

Martin Nagelkirk
Extension Educator, Sanilac County

An estimate of the yield potential of individual wheat fields during early spring is an important basis for management decisions. Plant density, along with considerations for production factors, can be useful in establishing a reasonable approximation.

Plant density within a wheat stand is usually the single most important indicator of yield potential. However, determining the number of live plants during green-up is not always easy, especially where winterkill is suspected. For example, brown and dried leaves do not necessarily indicate winterkill as these fall-generated leaves can be killed without reducing the plant’s chance for survival. On the other hand, an initial flush of green top-growth does not guarantee a plant will survive. The reason for this is that temperatures are sometimes cold enough to destroy the crown’s ability to grow new roots, but not cold enough to destroy the more resilient shoot-regenerating part of the crown. Fields that appear to be damaged should be revisited one or two weeks following green-up to determine if plants have actually survived.

Where winterkill is a factor, wheat plants should be inspected for new white roots growing from the crown. To speed the process, plants can be taken from the field and, after removing the soil, held at room temperature. To insure that the crown and roots remain moist, a paper towel or sealed plastic bag can be used. After four days, a viable crown should be producing new roots.

Once the density has been estimated, the table can be used to suggest a range of potential yields. The table provides yield estimates as a percent of that normally attained under good agronomic conditions. For each plant density, the yield potential is given in a “low-estimate” and a “high estimate” column. The lower yield potentials should be considered when an individual field is exposed to significant yield-limiting circumstances. For example:

§      Fields that were planted four weeks or more beyond the Hessian fly-free date (delays to this extent often result in yield reductions of 10 to 20 percent);

§      Wheat seedlings experienced repeated and prolonged periods of saturated soils (common poorly drained or non-tiled fields); and

§      Fields where adverse winter conditions injured plants (“winter injury” as opposed to “winter kill”) exhibiting slow development, poor coloring and generally poor vigor.

The suggestions provided here should be tempered, of course, by a grower’s experience. Consideration should also be given to the assessments of other veteran growers or experience field personnel that can visit the field in question.

Early spring estimates of wheat’s yield potential at low and high levels       

Plant density

Yield potential %

 Plants / ft (7 ½" row

 spacing)

Low estimate

High estimate

5

50

65

6

52

70

7

55

75

10

59

80

15

64

90

22

70

100

Winter wheat response to nitrogen

Darryl Warncke
Crop & Soil Sciences

Winter wheat response to topdress application of nitrogen may vary from year to year. Nitrogen response studies were conducted for three years at the MSU Agronomy Farm on a Capac loam, south of the main campus. Some of the variability in response is related to soil moisture status as it affects N availability, and to N source. In 2004, “Hopewell” soft red winter wheat responded well to nitrogen applied just prior to green-up (Table 1). Broadcasting 60 lbs N/acre resulted in an 11 bushel per acre increase. The yield difference between the 60 and 120 lbs N/acre rates was not statistically different at the 90 percent confidence level, even though the average yield was 7 bushels greater. Topdressing 60 lbs N/a (total N applied was 85 lbs/a) resulted in the best combination for economic return and minimum residual N in the soil. In that year, soil moisture conditions turned dry after N application at the Feekes 6 stage. Therefore, splitting the N between green-up and Feekes 6 did not prove beneficial (45+45 treatment).

In 2005, limited rain occurred in April and May, so movement of the surface applied N into the soil and root zone was limited. Considerable volatile N loss occurred from urea and UAN (28% liquid). Even so, the yield increase with 60 lbs N/ a broadcast was similar to that in 2004 (12 bu/a). Where ammonium sulfate was the N source, little volatile N loss occurred, and the yield with 90 lbs N/acre was 78.3 bu/a compared to 64.3 bu/acre for urea or UAN. In 2006 soil moisture was good throughout most of the spring/summer growing period, so considerable N was released from the soil organic matter. Hence, response to applied N was less. The variety “Roan” (grown in 2006) is a high yielder, but is susceptible to lodging. Heavy rains and strong winds caused the wheat to lodge about 3 weeks prior to maturity in all plots receiving 60 lbs or more of N. The severe lodging probably moderated any potential yield response to N rate. With urea and UAN applying 30 lbs N/acre resulted in as good a yield as 90 lbs N/a either all prior to green-up or by split application.

Interestingly, ESN (a controlled release polymer coated urea) applied at green-up in 2006 to supply 30, 60 or 90 lbs N/acre resulted in less severe lodging, and yields of 93.7, 106.1 and 105.7 bu/acre, respectively. Perhaps this was related to the gradual release of available N. In the dry spring of 2005, ESN applied to supply 60 and 90 lbs N/acre resulted in yields similar to those attained with ammonium sulfate, and those yields were higher than yields attained with urea or UAN. Apparently, with the warm dry soil conditions in 2005 there was significant loss of N by volatilization from urea and UAN, which did not occur with the polymer coated urea (ESN) or ammonium sulfate. Hence, soil moisture and rainfall conditions can greatly influence the release of N, and the loss of N from the various N sources.

Based on the results of these three years, it appears that wheat yield response to nitrogen is influenced by a combination of weather and N source. Under dry soil conditions the potential for volatile N loss is greatest with urea and UAN. The risk of N loss can be moderated by applying some of the N as ammonium sulfate or ESN. Across all the years, topdressing 60 lbs N/a (total of 85 lbs N/a for the crop) as urea or UAN resulted in near the best economic return. This was also the case with ESN and ammonium sulfate in 2004 and 2006. With the dry spring of 2005 applying 90 lbs topdress (total of 115 lbs N/a) as Ammonium sulfate or ESN resulted in a better economic yield. Using a combination of urea or UAN with either ammonium sulfate or ESN prior to or near green-up to supply 60 to 90 lbs N/a appears to be appropriate. This year with the higher cost of N staying closer to the 60 lbs N/a topdress rate may provide the best economic return. This assumes about 25 lbs N/a was applied at planting last fall.

Table 1. Soft red winter wheat response to nitrogen rate topdressed near green-up.

Topdress

 

 

Wheat Yield1

 

 

N Rate

2004

2005

 

2006

 

lb N/a

 

 

bu/acre

 

 

0

75.2

52.7

AS 2

88.4

ESN 2

30

- -

- -

(66.0)

95.2

(93.7)

60

86.1

64.6

(67.5)

91.5

(106.1)

90

89.4

64.3

(78.3)

95.3

(105.7)

120

93.4

- -

 

- -

 

45 + 45 UAN

76.6

- -

 

95.9

 

variety

Hopewell

 

Sisson

 

Roan

1 Average for Urea and UAN (28 % N) treatments except where indicated.

2 AS =Ammonium sulfate or ESN as N source .

Grown at the MSU Agronomy Farm, East Lansing, MI.

Capac loam. 25 lbs N/acre applied at seeding in the fall.

New seeding of Roundup Ready alfalfa halted

David Hillger
Crop and Soil Sciences

As some of you are likely aware, a U.S. District Court in California has issued a temporary injunction that prohibits the planting of Roundup Ready alfalfa after March 30, 2007. This injunction was in response to arguments made against the procedures the USDA followed prior to deregulating glyphosate-resistant alfalfa in June 2005. The question at the center of this legal battle is whether the USDA conducted proper testing of glyphosate-resistant alfalfa, specifically the risk of unwanted pollen movement from glyphosate-resistant varieties to non-resistant varieties under normal production settings. This movement has the potential to impact two groups of alfalfa growers: organic producers and conventional alfalfa seed producers. The judge has scheduled a new court date of April 27, 2007, to hear arguments pertaining to making this injunction permanent from both sides of this issue.

In the meantime, all Roundup Ready alfalfa that was seeded prior to March 30, 2007, is exempt from this ruling and can be harvested, sold and fed to animals. Any Roundup Ready alfalfa seed purchased before March 12, 2007, must be planted before March 30, 2007. After this date, all alfalfa planted must be a conventional, non-glyphosate resistant variety.

It is important to note that this legal battle is centered on the USDA and their registration procedures for the release of glyphosate-resistant alfalfa. Monsanto and Forage Genetics, the two companies that developed glyphosate-resistant alfalfa, are not mentioned in the lawsuit. Furthermore, the concern is with the potential of pollen movement from resistant to non-resistant alfalfa and not the feed safety of the alfalfa itself. The final outcome of these procedures could have a lasting impact on the use of glyphosate-resistant alfalfa and how future genetically-engineered crops are deregulated. It is safe to say that whatever the outcome of this hearing, an appeal will be filed by the losing party and additional lawsuits will be filed. This will likely take several months to a year(s) before a final verdict is the reached.

As more information becomes available, MSU will pass it along to you. More information about this can be found at: Monsanto’s website, monsanto.com, and the most recent court filing from the U.S. District Court for the Northern District of California: http://www.cand.uscourts.gov/cand/judges.nsf/61fffe74f99516d088256d480060b72d/624a62464b9c75078825729c0073563d/$FILE/6-1075%20Geerston%20Farms%20v.pdf  

Farm sprayer “tune up”

Ned Birkey,
Monroe, Wayne and Washtenaw MSU Extension EANRA

With the possibility of Asian soybean rust coming to Michigan this summer, and with the very likely probability of soybean aphids returning, early April may be the best time to “tune up” your farm sprayer. Insecticide and fungicide spraying will require more thorough leaf coverage and deeper into the foliage than glyphosate or most other herbicide sprays.

A ground-based, farm field crop sprayer needs to be calibrated at least once per growing season to be sure that it is in good working order and that the nozzles are applying the proper flow rate. With a sprayer in good working order, a tank that is half full of water, and knowing the proper nozzle flow rate, calibration should take about an hour or less.

The two primary things to check are the tractor ground speed and nozzle flow rate. I usually set up a 200-foot course, ideally in the field, to check ground speed of the equipment once as it goes down the course and then again coming back. Pulling the sprayer with a tank half full of water will give an approximation of average travel conditions. Remember to write down the gear and the engine rpm setting for actual spraying.

Then with the tractor parked and the engine running at the ground speed rpm setting, turn on all the spray booms. Before this, I replace the outside nozzle of one boom with an oil filled pressure gauge. The pressure at the boom is the actual operating spray pressure, regardless of what the gauge in the tractor or by the sprayer controls reads. With the sprayer operating at the proper pressure, now you can check the nozzle flow rate of the other nozzles on that boom and compare this amount to the nozzle company reference book. Repeat this process with all the sprayer booms.

MSU Extension has a free calibration sticker, AM-53, that can be affixed to the sprayer to help the farmer with one simple nozzle calibration procedure. Extension also has bulletins dealing with sprayer calibration, and the Pesticide Core Training manual, E-2195, has some excellent calibration information.

Remember to write down the sprayer calibration date for Michigan Right-to-Farm record keeping. Right-to-Farm also suggests that farmers have a portable spill kit available and a portable mix-load pad if they are mixing and loading pesticides in the field. Write down all the weather conditions when spraying to help you recall the wind direction and speed in case of a drift complaint.

Enviro-weather is geared-up for the 2007 growing season

Mark Trent
Enviro-weather

Ready for its second season, the Enviro-weather website is all set to be your source for agricultural weather and weather-based plant and pest management decision making tools. Just visit http://www.enviroweather.msu.edu and you will have access to information and management products from 49 weather stations across Michigan.

Weather information such as National Weather Service local forecasts and real time radar, overnight temperatures and weather summaries, including temperature, degree days and rainfall can be accessed by clicking on the weather station of interest to you. In addition, you can get summaries and decision making products specific for your favorite crop or area of interest by choosing from links to potato, forestry and Christmas trees, fruit or turfgrass. In addition, plans are underway for a field crops section on Enviro-weather.

New workgroup being formed for field crops

Enviro-weather invites self-identified workgroups to provide direction on tailoring the information system. These workgroups typically include website users such as farmers, resource managers and consultants along with MSU specialists and Extension educators. They are essential in identifying needs and priorities:

§      Are relevant weather-driven models/information available for integration into the system?

§      Which educational, extension and research resources should be linked to the system?

§      What supplemental external resources for research, partnerships, funding are needed?

§      Are additional weather stations needed and if so, how will they be supported?

A new workgroup is being formed to answer these questions relating to field crops. If you have input pertaining to the items above or would like to be part of the workgroup, contact Mark Trent at trentm@msu.edu or (517) 432-6520.

Enviro-weather tip

For easy access to Enviro-weather’s homepage just type “enviro-weather” in the Google search engine and click “I’m Feeling Lucky.” In most other search engines Enviro-weather will be at the top of the results list. Watch future editions of Field Crop CAT Alert for more Enviro-weather tips.

Water use reporting for 2006 irrigation

Agricultural irrigators are required by law to report their 2006 water withdrawals to the Michigan Department of Agriculture by April 1, 2007. Producers that have the capacity to withdrawal more than 70 gallons per minute of water need to report their water usage. Water withdrawals can be reported as either gallons per acre or acre inches applied each month.

Baseline Capacity (Rated Capacity) Establishment: Producers have a one-time option to report, as part of their 2006 water use report, the available capacity of a system to withdrawal water to establish a “Baseline Capacity.” The baseline capacity of the system should be reported as pump capacity in gal/min. along with a pump and system description which is compatible with the well log. Baseline capacity applies to both wells and surface water withdrawals. Please note: You should report this baseline capacity value on the water use reporting form on the line listed as “Rated Capacity.”

From the legal perspective, the Baseline Capacity is the reported system capacity used or developed to make a withdrawal on or before February 28, 2006. If a large capacity water user does not report a "Baseline Capacity,” MDA will use the highest annual amount of water withdrawn as reported for 2004 or 2005 and calculate one. Note: Since few producers run pumps continuously, most water users have available system capacities which will greatly exceed the amount of water that has been reported in 2004 or 2005. Establishing a baseline capacity is important since P.A. 33 provides a statement that existing water users are granted a rebutable presumption of no "adverse resource impact.” No adverse resource impact is the standard that all large capacity water users must meet within the P.A. 33 structure. The reputable presumption of no adverse resource impact puts the burden of proof on those challenging a registered large capacity water user’s water use. Expanding system capacity by more than 70 gallons/min beyond the baseline (rated) capacity, constitutes a new water withdrawal.

For more information on water use reporting or the baseline (rated) capacity, contact the St. Joseph County MSU Extension Office at (269)-467-5511 or visit the St. Joseph County MSU Extension Irrigation Website developed by Lyndon Kelley, the MSU/Purdue Extension Irrigation Educator, at: http://www.msue.msu.edu/portal/default.cfm?pageset_id=28706&page_id=361029&msue_portal_id=25643

Southwest Regional Report

Bruce MacKellar

While there is not much activity to report this early in the season, I did want to provide a short report for the southwest. The region held consistently more snow cover than is normal in February and March. This has reduced the ability for producers to early apply potash and lime on fields on a pretty significant scale, especially for those producers that are east of the US-131 corridor and are generally able to start trafficking fields in early March. The silver lining, if there is one for this delay, is that soil moisture levels are looking very good as we head into the 2007 growing season.

Commodity reports

Diane Brown-Rytlewski submitted an article in this edition of the Field Crop CAT Alert that deals with the potential for corn flea beetle survival and the subsequent increased potential for Stewart’s wilt disease in seed corn. Based on the late season incidence of Stewart’s disease causing foliar symptoms on commercial corn last season, seed corn producers need to be on the lookout for flea beetles early this season.

We also know that there will be a significant increase in the number of seed corn acres produced in southwest Michigan and Northern Indiana this year. Some of these acres may be going into fields where either commercial corn or seed corn was raised in 2006.

It may be prudent to consider moldboard plowing down the crop residue on these fields to help reduce the source on inoculums for leaf disease such as northern corn leaf blight or gray leaf spot. We did see a fair amount of northern corn leaf blight in St. Joseph and surrounding counties last summer. Gray leaf spot is generally not a problem in Southwest Michigan unless temperatures are very high (upper 80s to 90s) and field conditions are wet for an extended period of time.

With the wet harvest conditions last fall and the potential for delayed planting dates for wheat, some producers may want to evaluate their stands to look at yield potential for their fields. With corn and soybean pricing opportunities looking strong, poor stands of wheat may not be worth keeping during this season.

Soybean cyst nematodes continue to be a significant issue, particularly in St. Joseph County. Industry resources are suggesting that around 70 percent of the soybeans being planted in the county are soybean cyst nematode resistant. If you have fields that you suspect have soybean cyst nematode infestations, there are many glyphosate resistant varieties that are well adapted and yield well for our region. For those of you that are planting soybeans on fields that have significant populations of soybean cyst nematode in past years, it may be wise to look at the source of resistance that your soybean cyst nematode resistant beans are and to consider trying more than one source of resistance on your farm.

In a November 13 article, Iowa State Soybean Specialist Dr. Greg Tylka reported only about 3 percent of the resistant varieties available for 2007 have a source of resistance other than PI88788. There is concern that repeated use of a single form of the SCN resistance may lead to nematodes that will not be controlled by this source of resistance. The MSUE Field Crops AoE Team will be hosting a series of three research trials this summer looking at the effectiveness of different sources of soybean cyst nematode resistance in reducing nematode populations over the growing season. Talk to your seed agronomist for more information on the source of resistance for soybean cyst nematode resistant soybeans you are raising, or you can visit the following website provided by the University of Illinois Extension: http://web.extension.uiuc.edu/livingston/reports/i120/index.html

Irrigation

Some new tools have been developed at MSU to help with irrigation scheduling for corn, seed corn and soybeans for the 2007 growing season. A web-based irrigation scheduling program is being developed by Dr. Jeff Andreesen, MSU Agricultural Climatologist, and Dr. Steve Miller, MSU Department of Bio-Systems Engineering. A second stand-alone system (based on a Microsoft X-Cel spreadsheet design) is also being developed. Both systems will be capable of utilizing inputs from the Michigan Automated Weather Network (MAWN) and will be accessible through Enviro-weather. The rainfall and evapotranspiration data will be collected automatically from the closest weather stations on the web based system, whereas it will have to be entered by hand with the stand alone system.

Water use reporting

Just as a reminder, the last day for reporting your irrigation water use for 2006 and establishing a baseline or rated capacity for your withdrawals is April 1, 2007. Forms and more information is available from Lyndon Kelley, the MSU/Purdue Irrigation Field Specialist at his website at: http://www.msue.msu.edu/portal/default.cfm?pageset_id=28706&page_id=361029&msue_portal_id=25643

Weather news

Jeff Andresen
Agricultural Meteorology
Geography

Following an abnormally cold, wet October, record or near record warmth for much of November through early January, and winterlike conditions for much of February, more seasonable weather has finally materialized across Michigan during March. Most significant off-season weather developments to report would include above normal precipitation totals and a relatively mild soil temperatures due to abnormal warmth in December and January and later, to extensive snowcover in February and early March. The mild overwinter soil temperatures may lead to some extra insect and possibly disease pressure to deal with this year (e.g. flea beetle and Stewart’s wilt).

There is good and bad news regarding the above normal moisture. The bad news is that it will likely lead to some delays in early spring fieldwork during the next few weeks. The good (and probably best) news is that much of the state will enter the growing season with a rooting zone with a full or nearly full soil moisture profile, which may become indispensable later in the season should any prolonged dryness develop (not expected at this point). The latest Palmer Drought Severity Index values for the state categorize all of the Lower Peninsula as “unusually” to “extremely moist” with “near normal” values for the Upper Peninsula. This is a definite improvement for many sections of the Upper Peninsula (especially western sections) which experienced drought conditions much of the past year.

Looking at the current weather situation, a very springlike upper air pattern was in place across North America on March 22, with a trough of low pressure located across much of the western United States and a ridging pattern covering much of the east. This general pattern is expected to continue for much of the next couple of weeks, which should lead to warmer than normal temperatures and normal to above normal precipitation totals across the Great Lakes Region with an active storm track in place through the central United States.

In the short term, an area of low pressure over the central Great Plains region Thursday (March 22) morning will slowly move eastward towards the Ohio Valley during the next 24 hours, setting the stage for more rainfall across southern sections of Michigan on Friday into early Saturday. Central and northern sections of the state will likely remain dry through Sunday. A frontal system will approach the state by late Sunday and Monday, bringing another chance for showers and possible thunderstorms. Temperatures will remain at near to above normal levels, with highs ranging from the mid- and upper 40s far north to the low 60s south and lows ranging from the upper 20s north to the upper 30s or low 40s south. Cooler and drier weather is likely by the middle of next week, although any cooling trend should be short-lived.

Current medium‑range forecast guidance strongly suggests the overall continuation of the current upper air pattern, with ridging across much of the central and eastern United States. This pattern would suggest warmer than normal temperatures including the possibility of severe weather across the region. The official NOAA 6-10 day and 8-14 day outlooks (covering March 27-31 and March 29 through April 4) both call for above normal temperatures across Michigan and much of the eastern United States. Precipitation is forecast to range from near normal levels across southeastern sections of the state to above normal levels in the northwest.

Long lead outlooks

During the past couple of months, the El Nino and warm water conditions of last fall have rapidly dissipated. Sea surface temperatures in the central equatorial Pacific region haven fallen back to near normal or even slightly cooler than normal levels. With this reversal, there is now a chance for development of a La Nina or cool ENSO event within the upcoming months. Given the current near-neutral conditions, however, potential ENSO-associated weather anomalies across North America during the next few months will likely be limited to southern sections of the United States, if at all.

Latest NOAA CPC long lead outlooks for Michigan have shifted towards more uncertainty. Both the official one-month and three-month outlooks for the month of April and April-June periods, respectively, call for near equal odds of below-, near-, and above-normal values or temperatures and precipitation over most areas of the state. An exception would be western sections of Upper Michigan (as well as sections of the Upper Midwest and Great Plains to the west of Michigan), where the outlooks suggest above normal temperatures and possibly to above normal precipitation totals during April.