In this issue
Mild winter leads to early season insect problems
Butterflies, moths, skippers, oh my?
Winter annuals and insects
Dandelion management in field and forage crops
Delayed herbicide application in corn
Delaying burndown herbicide applications in no-till soybean can reduce yield
Growing non-GMO soybeans: What do you need to know?
Weed control options if a micro-rate application timing is missed in sugar beets
Section 18 exemption granted for Reflex use in dry beans
Soybean rust factsheet now available
Using models to predict fusarium head blight and DON levels in wheat
Folicur fungicide for wheat head scab
Soybean aphid control with seed-applied insecticides
Manganese deficient wheat
Regional reports
Schedule of Small Flock Avian Influenza H5N1 Meetings
Weather news

Mild winter leads to early season insect problems
Christina DiFonzo, Entomology

Alfalfa weevil
Mike Staton and Paul Wylie in southwest Michigan reported first instar alfalfa weevil larvae feeding last week; as the weather warms back up, expect an increase in activity. The easiest scouting method uses “tip injury.” Survey across the field, not just on an edge. Check tips of 100 stems for feeding. Treat if 40% of stems show damage AND the field won’t be cut for at least seven days. An alternative scouting method is the “stem and bucket” threshold from Ohio State University. Snap off 30 stems at random from a field and place in a bucket. Shake the stems to knock off late instar larvae (the big guys). Don’t worry about the little larvae. Count the total number of larvae in the bucket. Then randomly select 10 of the 30 stems you just picked, and measure the average stem height (I marked a ruler on the handle of my sweep net). The treatment threshold, in number of larvae per 30 stems, varies with average stem height in inches, as follows:

• 12 inches - 30 to 50 larvae
• 16 inches - 40 to 75 larvae
• 20 inches - 45 to 85 larvae
• 24 inches - 50 to 90 larvae

If a field is over threshold but will be cut within the next week, consider cutting early to kill weevils. This is the preferred control method because it preserves natural enemies and pollinators, and saves insecticide cost. Also, most insecticides cannot be used within 7-21 days of cutting, depending on the product. After cutting, remember to check for weevil larvae on the regrowth, which can delay or prevent green-up. The threshold after cutting is 6 to 8 larvae per square foot of regrowth.

If forage quality might be adversely affected, cutting may not be possible. If you decide to treat, remember to note the pre-harvest interval (PHI) of insecticide. The PHIs range from 0 to 28 days, depending on the product and rate per acre. Also remember that there are many beneficial insects in alfalfa that are killed by sprays and that most labels now include honeybee warning statements. Fields in bloom should never be sprayed because all of the insecticides registered for alfalfa are toxic to bees – these fields should be cut.

There is no defined threshold for this pest in beets and little research data on springtail control in crops using foliar sprays. Few insecticides list springtails on the label. However, insecticides registered on sugar beet to control other pests can be used against springtails – the site/crop is the legal issue, not the specific pest (this applies to the United States, not to Canada). The following products are being used on beets, and are reducing springtail damage. My senses is that a half rate – maybe even a 1/3 rate – is enough to take care of the problem.

Product name (full label rate)

• Asana XL (5.8 to 9.6 oz/acre)**
• Lannate 2.4LV (0.75 to 3 pints/acre)
• Lannate 90SP (0.25 to 1 lb/acre)
• Lorsban 4E (1.33 pints banded/acre) **
• Mustang (2.4 to 4.3 oz/acre)

To control caterpillars in timothy, the only registered option is Bt, specifically Dipel. Read the label thoroughly. Small larvae are much more susceptible to Bt than larger larvae, and good coverage is essential.

For a bulletin on skipper management, see this publication from Ontario:
http://www.omafra.gov.on.ca/english/crops/pub811/5skppr.htm

For pictures of adults, see the Wisconsin or Michigan butterfly web sites:
http://www.wisconsinbutterflies.org/butterflies/species/226
http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/mi/564.htm

What’s a butterfly? What’s a moth? What’s the difference? And what the heck is a skipper? Here’s the low down:

Butterflies (view pictures)

• Antennae: long, thread-like, with a knobby-bit at the end
• Wings: At rest, held together up over the body (rarely extended flat to bask in the sun)
• Habits: Active on sunny days. Often seen on flowers or around puddles
• Examples: Monarch butterfly, swallowtails, sulphurs (yellow butterflies common at puddles in the summer)

Moths – many common pest species

• Antennae: usually combed, plumy, or featherlike. Never knobbed.
• Wings: Held out flat, or wrapped down or around body.
• Habits: Most are nocturnal. Fly at night, may come to lights.
• Examples: Cecropia, sphinx moths (hold wings flat); European corn borer, Indianmeal moth, gypsy moth (fold wings back or around body).

• Antennae: Long, thread-like, with a hook at the end. (I like to describe it as a banana.)
• Wings: At rest, held together up over the body.
• Habits: Active on sunny days. Often seen on flowers.
• Examples: European skipper; silver spotted skipper (pretty caterpillar with a huge head is sometimes found in rolled up soybean leaves).

There is a tremendous amount of low-growing weeds this spring. These weeds may be attractive to certain insects, especially cutworm, that lay eggs in weedy corn. Thus, timely weed control is critical to reduce infestation.

Weeds may also impact seedcorn maggot. A newly killed or tilled weed mat may be highly attractive to egg-laying females for several weeks as the weeds decay. If you expect this to be a problem, there are many seed treatments for corn and few for soybeans that can be used to reduce maggot damage.

Dandelion continues to be a serious problem in Michigan, mainly in no-tillage fields. Regular soil disturbance is effective at preventing the establishment of dandelion plants; however herbicide options are available to suppress dandelion in corn, soybean and alfalfa.

Research conducted at MSU in 2001-03 studied the control of dandelion in no-till corn and soybean. The results showed that herbicide applications of either glyphosate (0.75 lb a.e/A. + 17 lb/gal AMS) or 2,4-D ester (1 lb a.e./A) are more effective in the fall than in the spring. Additionally, 2,4-D ester was less effective than glyphosate in both fall or spring applications. Details on the results of this research are in the fact sheet, which also appears in the 2006 Weed Control Guide for Field Crops, pages 150-151.

The best approach to dandelion control is prior to planting a crop. However it is not uncommon for herbicides to provide less than complete control, especially if applied in the spring. What are options for dealing with uncontrolled dandelion following crop emergence? Where corn or soybeans have emerged and established dandelion are present, the strategy should be to suppress the plants to minimize yield loss from dandelion competition. In-season applications will significantly reduce dandelion competition but will likely not greatly reduce dandelion population. Then a fall application can be planned following harvest with the goal of actually removing the plants.

Corn. Several postemergence provide significant dandelion suppression. These are listed in the fact sheet, which also appears in the 2006 Weed Control Guide for Field Crops, pages 150-151.

Soybean. Glyphosate is the best option for postemergence suppression of established dandelion.

In established alfalfa, dandelion can be controlled with Velpar. The treatment can be made in the fall or spring; however the most effective timing for dandelion control is in the spring before the alfalfa has two inches of new growth. The best timing for maximum crop safety is early spring before the alfalfa breaks dormancy. The application rate for dandelion control is 1 lb ai/A. Velpar is not widely used for dandelion control due to cost and rotation crop restrictions. Dandelion control in Roundup Ready alfalfa can be achieved with an application glyphosate (0.75 lb a.e/A. + 17 lb/gal AMS).

There can be many challenges for herbicide application following planting such as high winds and rainfall. Therefore, it is likely there will be situations where corn has emerged before preemergence herbicides have been applied.

In fields with emerged corn and no herbicide applied, growers have two primary options: 1) use an herbicide program typically applied before emergence; or 2) switch to a total postemergence strategy. There are several possible herbicide programs with each strategy.

Table 1K (pg. 49) in the 2006 Weed Control Guide for Field Crops lists herbicides typically applied preemergence. Many of these herbicides are also labelled for application after corn emergence. Axiom and Princep should only be applied before corn emergence. To avoid confusion, tank mix combinations are not included this table. Details on the specific restrictions for tank mixtures can be found on the herbicide labels. Although some herbicide labels allow application to emerged corn using 28% liquid nitrogen fertilizer as the herbicide carrier, we advise that all herbicide treatments to emerged corn be applied with water as the carrier. Applying herbicides to emerged corn with 28% liquid nitrogen as the carrier poses a risk of severe crop injury. This risk is increased under cool, cloudy conditions prior to application, a common occurrence in Michigan.

Preemergence herbicides should be applied as soon after planting as possible. Delayed application increases the risk of poor herbicide performance, especially for grass control. When herbicide application is delayed until after crop emergence, rotary hoeing is recommended. The rotary hoeing may be done before or after the herbicide application, but must be done when the weeds are very small. If the delayed application includes Banvel/Clarity, Distinct, Marksman (or other herbicides containing dicamba) or Prowl/Prowl H 2O/Pendimax, crop safety will be greater if the rotary hoeing is done before herbicide application.

Herbicide options for total postemergence weed control are dependent on the seed planted in the field. Many postemergence herbicides can be used on any corn hybrid, while others such as Liberty, Lightning and glyphosate require herbicide resistant hybrids. For details on postemergence herbicides for corn, see Extension Bulletin E-434.

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. These delayed burndown applications can reduce soybean yield by inhibiting soybean emergence and growth. Also, by delaying these applications weeds become larger and can often times can be tougher to control and many times dense weed populations (or mats) can even interfere with planting. Competition from these early-season weeds can reduce soybean yield by as much as 16% (8.3 bu) (Figure 1).

Additionally, these carpets of weeds can harbor soybean insects and diseases causing additional problems for the soybean crop. Remember early control of these weeds is important. If a burndown herbicide application can not be made prior to planting, it should be made shortly thereafter. Any delays in these applications can reduce soybean yield. A complete listing of burndown herbicides and their effectiveness ratings can be found in Table 2C of the 2006 Weed Control Guide for Field Crops (E-434). Remember treatments that contain 1 pt/A of 2,4-D ester need to be applied a minimum of seven days before soybean planting.

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.

1) It is important to start clean! As with all weed control strategies, starting with a weed-free seedbed is essential. This can either be done with tillage or an effective preplant burndown herbicide treatment. In no-till soybeans using an effective burndown treatment is particularly important since typical postemergence soybean herbicides will not adequately control typical no-till weeds. For adequate control of several of these no-till weeds, 2,4-D, glyphosate, or a combination of the two should be used in the burndown treatment. When including 2,4-D ester in the burndown treatment this application should be made at least 7 days prior to soybean planting.

2) Producers of non-GMO soybeans should also consider using a preplant or preemergence herbicide with residual activity as a foundation program for hard to control weeds such as common lambsquarters, common ragweed, giant ragweed and eastern black nightshade. Relying on a total POST program for control of these weeds can be difficult. Control of these weeds has also been difficult in Roundup Ready soybeans programs so it is important to control these species with a two-pass herbicide program. By waiting to control these weed with a total POST program many times these weeds can become too large, may be affected by the environment (hardened off by hot-day weather) or may just not be effectively controlled. Getting a start on controlling these weeds early in the season will insure greater overall success for your weed control program. Also using a two-pass program with a preplant or preemergence herbicide application limits the use of “rescue” herbicide treatments late in the season that can further stress soybean growth on previously injured soybeans.

3) Make timely POST applications. Many producers have been accustomed to controlling large weeds by increasing the rate of glyphosate in Roundup Ready soybean. Unlike glyphosate many of the POST herbicides used in non-GMO herbicides are not very effective on large weeds. It wasn’t too long ago when the application window for POST applications in soybean was between 2 and 4 inch tall weeds. So, remember when using a non-glyphosate based program herbicides need to be applied before weeds exceed 4 inches tall for adequate control. Applying a preplant or preemergence herbicide will also help extend this window by providing some early season control of these weeds.

4) Are herbicide resistant weeds a problem on your farm? There are several populations of ALS-resistant and triazine-resistant weeds around Michigan. If herbicide resistance has been a problem on your farm in the past take this into account when planning your weed control strategy in conventional soybeans. For example, if you have ALS-resistant common lambsquarters relying on a POST program of Harmony GT or Raptor would not control this weed. However, there are several soil-applied herbicides that can effectively control common lambsquarters season-long. To determine the effectiveness of herbicides on common lambsquarters and several other weeds consult the MSU Weed Control Guide for Field Crops (E-434) http://www.ipm.msu.edu/cat06field/06weedguide.htm.

For weed control in non-GMO soybean I strongly recommend a two-pass program that consists of a preplant or preemergence residual herbicide followed by a postemergence program. Using a two-pass program with a residual herbicide may add to the overall cost of your weed management program but this program will result in overall more consistent control of several weed species and help protect your soybean yields.

Weed control options if a micro-rate application timing is missed in sugar beets
Christy Sprague
Crop & Soil Sciences

With this year’s sugar beet growing season in full-swing, timely weed control measures are extremely important. Rain, wind and equipment breakdowns can cause delays in timely postemergence herbicide applications leading to reduced weed control. This is particularly important with micro-rate herbicide programs. Missing an optimum micro-rate application timing can lead to the reduced effectiveness of the entire weed control program and will also cause several weed control headaches as the season progresses. So what are some of the options that can be done to control these weeds if we miss a micro-rate application timing? Below are some of the factors that should be considered in choosing alternative weed control strategies if a micro-rate application timing is missed before the weeds become too large and require hand labor.

Was a preemergence (PRE) herbicide used on this field? If a PRE herbicide was used this could impact the susceptibility of the weeds, as well as the potential susceptibility of sugar beets to increased injury. This factor should be considered when deciding on what weed control strategy to use. With cool, wet conditions, both weeds and sugar beets will be more susceptible to POST herbicides, particularly if there was a PRE herbicide applied. Keep this in mind when applying higher Betamix rates or when switching to a standard split herbicide program. Also, if a PRE herbicide was banded, check to see if there are any weeds emerging in the band. If weed control is good in the band, cultivation may be all that is needed.

Option B: Weeds are 1/4 inch tall. One option when weeds exceed the maximum size for a standard micro-rate herbicide application is to increase the rate of Betamix to 12 fl oz/A or 16 fl oz/A in the micro-rate application. According to the label, the rate of Betamix at 16 fl oz/A should only be increased if the smallest beets in the field are in the 4-true leaf stage. Increasing the Betamix rate may help control slightly larger weeds. Applications can be made later in the day to help reduce sugar beet injury. Also use caution when using higher Betamix rates if sugar beets are in the early 2-leaf stage. Sugar beets are more sensitive to stresses at this stage of growth.

Option C: Weeds are 1/4 inch tall. Another option is to make the standard micro-rate herbicide application when conditions allow and then shorten time period between before the next application. For example, if the second micro-rate application timing is delayed, you may want to decrease the amount of time between the second and the third application to 150 GDD. Larger weeds that are injured may be more susceptible to the third micro-rate application and won’t have completely recovered (the 1-2 punch!). Remember sugar beets will also be more susceptible and that could potentially lead to an increase in sugar beet injury or stunting, especially if conditions are cool and wet.

Option D: Weeds are 1/4 inch tall. Yet another option when the micro-rate herbicide application timing has been missed is to switch to a standard split low rate herbicide application. If you choose to switch to a standard split herbicide application, do not add MSO or surfactant to this application. Applications should also be made after 4:00 p.m. to reduce sugar beet injury. If weed control is adequate after the standard split application, growers can switch back to a micro-rate herbicide program (start GDD accumulation after the standard split application) or continue with a another standard split rate later in the season.

Option E: Weeds are 1/2 inch tall. If weeds reach 1/2 inch tall, it is best to plan on a standard split rate herbicide program. Apply the first split rate when sugar beets are less than the 4-true leaf stage. Weeds not completely controlled by this application will be controlled by the second application. The second application should be made 7 to 14 days after the first application. Applications of standard split rates should be made after 4:00 PM to reduce sugar beet injury.

This week the U.S. EPA has granted Michigan a Section 18 emergency exemption for the use of Reflex 2L (fomesafen) to control broadleaf weeds in dry beans in Michigan for 2006. The use of Reflex in dry beans has been contingent upon the renewal of the Section 18 for the last 10 years. Reflex has been an important tool for Michigan dry bean growers for postemergence control of broadleaf weeds, particularly common ragweed and eastern black nightshade. This year’s Section 18 is effective until August 15, 2006. All classes of dry beans are included on the label. Only one application of Reflex at 1 pt/A can be applied for weed control in a 2-year period (So if you applied Reflex to a field in 2005 you cannot apply Reflex to the same field in 2006.). A non-ionic surfactant at 0.25 to 0.5% v/v or a crop oil concentrate at 0.5 to 1.0% v/v must be included with Reflex for effective broadleaf weed control. Dry beans should be between the first and fourth trifoliate leaf stages at the time of application. Reflex applications should be targeted to control common ragweed up to four inches in height and nightshade species up to two inches in height (4 leaves).

Reflex will also control pigweed up to two inches in height. Reflex will control ALS-resistant biotypes of these weeds. Additional weeds may be controlled by tank-mixing Reflex with other herbicides. If proper planting intervals are not observed, Reflex can cause injury to rotational crops. Wheat should not be planted for four months and corn should not be planted for 10 months after an application of Reflex. Sugar beets, cucumbers and alfalfa cannot be planted for 18 months following a Reflex application.

Remember – you must have a copy of the Section 18 Reflex label when purchasing and applying Reflex to dry edible beans.

Soybean rust factsheet now available
A Soybean Rust Fungicide Use Guideline factsheet updated for 2006 is now avaialable as a pdf at: http://www.ipm.msu.edu/cat06field/pdf/5-4soybean.pdf

It is a tool to help you determine whether or not to apply a fungicide to your soybeans based on risk levels and whether rust is present. Fungicide basics are covered and the products labeled for use on soybean rust are listed in a table.

As mentioned elsewhere in this issue of the Field Crop CAT Alert (see Folicur Fungicide for Wheat Head Scab) a fungicide application must be timely to be effective. The window for application is very narrow – from 75% heading up to about 25% flowering – a period of only a few days.

Over the years several models have been developed to help growers predict in advance whether or not an application of tebuconazole will be needed to control Fusarium head blight (FHB) and the associated mycotoxin, deoxynivalenol (DON, vomitoxin) that develops in the wheat kernels. Two such models are the Penn State Model, which predicts the risk of FHB and the DONcast model, which predicts the levels of DON. Both of these models involve the use weather data and some observation of crop development stages on the part of the grower. This article will cover the Penn State Model. Next week, we’ll provide details about the DONcast model developed at Ridgetown University in Ontario, Canada.

The Penn State Model is designed to predict the risk probability of an epidemic with greater than 10% severity based on observed weather patterns. Different models are used for spring and winter wheat. The winter wheat model is based on the interval of time that relative humidity is 90% or greater with temperatures between 48 and 85°F (9-30°C). Regardless of the wheat class, you will need to identify the date at which 50% of the heads are flowering in your field. Wheat is most susceptible to FHB infection during flowering. The model uses weather conditions observed during the seven days prior to the flowering date you select to predict the level of risk. You can select a risk prediction based on the previous seven days’ weather, six days and a 24-hour forecast, or five days and a 48-hour forecast.

The Penn State model is available at the website http://www.wheatscab.psu.edu/. Select the risk map tool on the menu, then follow the directions to choose an assessment date, wheat type and state. Once you select the state ( Michigan), the weather station locations will appear on a map of the state. Clicking on an individual station (represented by a purple dot) will bring up the previous seven days’ temperature, rainfall and risk probability for that station point. The models are “tuned” to reflect average rainfall.

In the past, model predictions have not always reflected risk accurately when an area has been under extended periods of drought or higher-than-normal rainfall. A means to help address that issue has been to allow for input by the state Extension specialist to provide additional commentary that may not be reflected by the risk maps, including information about rainfall or drought conditions, and wheat growth stages in specific areas of the state.

The models have an accuracy of about 80% given the data used to develop and test the models. They are intended as a decision aid to be used along with other resources, such as weather forecasts, grain markets and local expert advice to help you with disease management decisions. Weather conditions that take place during flowering and grain fill of the crop are not part of the model and could significantly affect the development of disease and accumulation of mycotoxins. This year, Michigan is part of a pilot project that will allow for additional commentary on the risk maps. The commentary will provide information about rainfall, drought and growth stages of wheat in various parts of the state (not reflected by the risk maps), that we hope will enhance the usefulness of the maps. This commentary feature will only be available for Indiana, Kentucky, New York, Ohio and Pennsylvania.

A Section 18 special exemption allows the use of Folicur® fungicide again this year to combat fusarium head blight (FHB) of wheat. One application of Folicur at the rate of 4 ounces per acre may be applied up through early flowering (Feekes 10.51). Folicur may be applied with ground equipment or aircraft. Applications are not allowed within 30 days of harvest.

Fusarium head blight (FHB), commonly called head scab, is caused by several species of fungi in the genus Fusarium. While the disease is capable of causing a loss to of grain yield, the most significant financial losses result from the mycotoxin deoxynivalenol (DON or vomitoxin) which is produced by the fungi within infected kernels.

The severity of FHB depends mostly on weather conditions. Rainfall and a moderately warm environment at the time of flowering is most conducive to the pathogen and the single best basis for disease prediction. However, rainfall prior to flowering encourages the development of the pathogen’s spores, and moist conditions following infection of the flowering heads encourages the disease’s development. (View images) A model predicting the risk of scab can be found at:
www.wheatscab.psu.edu.

Beyond existing and predicted weather patterns, growers contemplating the use of Folicur might consider the following.

White vs red
Local market discount schedules for DON contaminated wheat varies, not only with current market considerations, but also by wheat type. Soft white wheat is often discounted more than soft red wheat due to milling product requirements. For example, white wheat discounts for white wheat grain might begin when DON levels reach 1 ppm, whereas contaminated red wheat may be acceptable until DON reaches 3 ppm. Therefore, the risk of financial losses from DON is greater for white wheat than red wheat.

Rotation and crop residue
FHB is much more prevalent on wheat that follows a crop of corn, as its residue serves as a host for a pathogen that causes both Gibberella stalk rot in corn and FHB in wheat. In no-till systems, even two-year-old corn residue on the ground surface may be a concern. Experience with the disease suggests that wheat following corn can easily double the severity of scab and resulting DON levels.

Folicur™ ( tebuconazole ) is a product of Bayer Cropscience. To be effective against FHB, Folicur 3.6 F must be applied on a timely basis. For best results, Folicur should be applied 1 to 3 days after 75 percent of the wheat is fully headed (the entire head has emerged beyond the flag leaf). Depending on temperature, this timing should correspond to when 25 percent or less of the heads have begun to flower.

If using ground equipment, Folicur 3.6 F should be applied at 4 ounces per acre with a pressure of 30 to 40 psi. The boom height needs to be adjusted to target the wheat heads. Researchers with the U.S. Wheat and Barley Scab Initiative suggest that the fungicide be applied with 10 gallons of water and a low rate of nonionic surfactant using either a single tapered flat fan nozzle oriented forward at 30º from horizontal or a double orifice nozzle (twin jets or twin nozzles) in a forward/backward orientation. They also suggest that the greatest disease suppression is attained with spray droplet sizes of 275 to 350 microns (industry category of large fine to small medium sized droplets).

A timely and thorough application of Folicur can reduce the severity of FHB by at least 50 percent. However, the application’s impact on DON is less predictable. Experience suggests that the use of Folicur often reduces DON by 0.5 to 1 ppm.

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.

In 2004, when aphid pressure was light, the soybean yield response to Cruiser and Gaucho averaged just under 1 bushel per acre over six locations across the state. Conversely, in 2005, with heavy early season aphid pressure, yield response to these seed applied insecticides averaged 6 bushel per acre across four Michigan locations. Results of the 2005 trials showed there was early season suppression of aphid populations through the R1 (flowering) growth stage. However, as aphid pressure increased over the growing season, the level of population suppression seen by the seed-applied insecticide treatments decreased significantly (see accompanying graph). Based on this data, it appears unlikely that an insecticide seed treatment would keep aphids from reaching economic threshold and prevent the need for a foliar-applied insecticide application during a heavy aphid pressure year. However, some yield benefit may be gained if early season aphid pressure is high.

Late summer scouting in 2005 and early season scouting this spring suggests that aphid levels may be down in 2006 throughout most of the state. However, some areas, especially those with nearby Buckthorn infestations, which serve as the overwintering host for the aphid, may experience high localized soybean aphid populations. In deciding whether to invest in these insecticidal soybean seed treatments, it is important to assess expected early season aphid pressure and weigh that against the cost of the product.

There have been few reports of manganese (Mn) deficient wheat growing on soils with pH above 7.0. Manganese deficient wheat has a general yellow-green appearance from a distance with interval yellow-green pin-stripping on the leaves. See figure 10 in MSU Extension Bulletin E-486. The plants may also appear moisture stressed even though there is adequate soil moisture. Manganese deficiency can be corrected by spraying the foliage with 1 to 2 pounds actual Mn per acre, depending on the severity of the deficiency. Manganese sulfate is the most effective material to use. Chelated or sequestered materials can also be used, but limit the amount applied with these two materials in any one application to 1 pound per acre.

Manganese availability in the soil decreases significantly as the soil pH increases. Manganese deficiency is most likely to occur on high organic matter soils with a pH above 6.5, on acid mineral soils that are lime to soil pH 6.5 or above, and on mineral soils with pH above 7.0. However, Mn deficiency will not occur on all mineral soils with a pH above 7.0. Mineral soils that are naturally alkaline (pH above 7.0) frequently contain adequate available Mn so a deficiency does not occur.

Regional reports
1 -- Southeast
Ned Birkey

Weather
It has been near normal recently, though the month of April was much drier and warmer than normal. We did have a nice soaking rain Tuesday (May 3) with rainfall amounts up to about one inch. Soil temperatures since April 12 have hovered above and below 50 degrees, which has slowed corn germination. A 26-degree hard frost last week on April 26 reminded farmers that we are not yet past the normal frost-free date for our area.

Commodity reports
Alfalfa is growing very well with a possible first cutting as early as next week for higher quality, feed value hay. We have not had an alfalfa weevil problem yet, though farmers should scout fields and possibly make a first cutting decision partly based upon the feeding caused by this insect.

Corn planting is mostly finished though germination has been slow. Acreage should be down, perhaps by ten percent or more based upon higher fuel and fertilizer prices. This spring I have run a number of soil fertility reports, as farmers want to compare MSU’s recommendation to the private laboratory report they received from their fertilizer dealer. There has also been more interest in side dressing and the MSU soil nitrate-testing program that we will offer later this month and prior to side dressing.

Soybean planting started after April 16 but at a slower pace than corn. Some farmers focused on planting corn first and are just starting soybean planting now.

Wheat has improved all during the spring and generally looks very good now. Plants are zooming past the Feekes’ growth stage six “benchmark”, earlier than normal, benefiting from the warmer April. Many fields will likely be at Feekes’ stage 7 by this weekend. Wheat continues to have a very good stand and fields look very clean. At the current rate of growth, wheat could come off early, perhaps even in very late June. 1998 we were heavy into wheat harvest on June 30, with balers and soybean drills following the combines around the field.

2 -- Southwest
Bruce MacKellar

Weather
Showers this last week brought a much welcomed reprieve from the frantic pace this field season has shown us so far. Widespread rainfall blanketed the region, with rainfall rates ranging from 0.3 to around 1.5 inches in widely scattered pockets. Field work was slowed down for about a day or so, and with drier conditions in the forecast for this weekend, field work will be back on track in a major way by Friday.

Commodity reports
Commercial corn planting is progressing very rapidly. In St. Joe County, planting is very nearly complete. Larger producers that have focused on “corn first” also have the majority of their acreage in. None of the early planted fields I have walked through have emerged at this point, but several must be close. Due to the heavy growth of winter annual species such as chickweed and purple deadnettle this warm spring, it may be prudent to keep an eye out for cutworm damage on fields that were tilled or planted after heavy growth had occurred. In some instances, we have seen pockets of seed corn maggot damage in fields where chickweed growth was heavy and “clumps” of this material were rotting on or near the soil surface. Insecticide-treated seeds may be a good choice in these fields, especially if you have had seed corn maggot challenges in the past. Most early weed control looks good at this point.

Planting preparations for seed corn are just getting underway. In sweep net sampling along the field edges, it is easy to find flea beetles.

Soybean planting starts very early in St. Joseph County, mainly to get it out of the way for seed corn planting and field prep. I think it is possible that 80% plus of the soybeans are planted in St. Joe, substantially less in other areas of the region.

Alfalfa growth has been quite good this spring. The crop was nipped by frost on April 26, but has been recovering quite nicely. Alfalfa weevil has been over threshold in a few fields, and sweep net sampling in St. Joe has revealed fairly high numbers of very small larvae and adults. Van Buren ANR Educator Mike Staton reports alfalfa weevil levels have been highly variable in fields in the Paw Paw and Niles areas with some fields above threshold and others not showing any sign of weevil or damage. Timely cutting kills most larvae, pupae and some adults. Consider early cutting rather than spraying to preserve natural enemies. Early season, use sweep net to detect adult emergence. Before first cutting, sample 20 stems in five different locations of the field; look for larvae and damage. After first cutting, check stubble or re-growth for larvae. Threshold: Before first cutting, treat when 40% of stems damaged, plus live larvae present; after first cutting, treat when 25% or more of new tips damaged, or 6 to 8 larvae per square foot of regrowth.

Wheat growth stages range from Feeke’s stages 7 to 9 with planting date accounting for most of the differences. Powdery mildew is present in some fields. Resistant varieties rarely show an economic benefit from fungicide applications for powdery mildew. Check the resistance ratings for the varieties you planted and consider this information when making management decisions.

3 -- West Central
Fred Springborn

Weather
Two weeks of relatively warm, dry weather has moved planting along at a better than average pace. High air temperatures have been in the 60s and 70s with lows ranging from 25°F on April 26 to 51°F on April 30. Low soil temperatures have been in the upper 40s to low 50 for most of the past two weeks. Moisture is generally adequate for seed germination. Some soils in some areas are still a bit too wet for field work to begin while other could use a bit more rain.

Commodity reports
Corn planting has progressed rapidly with a third of the crop planted and a small fraction of that just emerging.

Wheat is near Feeks stage 6 with few disease problems. Oat planting is 99% complete with most fields emerged.

Alfalfa is 8 to 10 inches in height with very little alfalfa weevil injury.

4 -- Central
Paul Gross

Weather
There were scattered showers over the region Monday and Tuesday (May 1-2), which keep planters in the sheds. Rain amounts ranged from 1/4 to 1/2 inch. Planting resumed Wednesday afternoon in most areas. Soil moisture varies with some areas on the wet side while others are on the dry side. Soil temperatures last week were 44 to 46 degrees. Planting will be at a fast pace as long as the weather cooperates.

Commodity reports
Corn planting is progressing at a fast pace with planting about 50% of the crop in the ground. Planting conditions are generally good especially on the lighter soils. Some of the early planted field should begin to emerge soon. Some farmers have all their corn in while others are just getting a good start.

The soybean crop is 10 to 15 percent planted. Planting really got underway last week where conditions allowed and will progress rapidly this week if the weather cooperates.

Wheat is in Feekes 5-6 with some later planted fields in stages 3-4. There has been no disease problems found at this time. We are seeing several fields on lighter soils that are yellow and not greening up as we would like to see. The warmer weather seems to be helping as will the top dressed nitrogen.

Oats has been planted and most has emerged and looks very good at this time.

Alfalfa is 8 to 10 inches tall and a little ahead of normal. Scout fields for alfalfa weevil. The weevil has been reported over threshold in southern counties. New seedings are planted and many have benefited from the light rains over the past few weeks.

Sugar beets are planted and beginning to emerge. Herbicide applications are beginning to go on. No problems reported at this time.

5 -- Thumb
Mark Seamon

Weather
Light rainfall on Monday (May 1) slowed planting early this week in some areas. The northern Thumb did not receive this rain causing some areas to be drier than normal. Soil moisture is good in most other areas with good emergence conditions.

Commodity reports
New growth looks good on established alfalfa stands.

Soil conditions for emergence of sugar beets are good in some areas. Other areas have dried below the seed and will be waiting for rainfall to germinate. Micro-rate herbicide applications have been made timely and weed control is good. Flea beetle and springtail feeding can be seen in many fields. Some insecticides are being mixed with micro-rate applications for insect control. A few beets were lost to frost injury but not widespread.

Wheat growth has been rapid this spring with many fields in the Feekes growth stage 7 and 8. Some fields are showing variable growth but most look good. .

Frost seeded clover has had good conditions for establishment with adequate surface moisture for germination. Powdery mildew can be found in the canopy but is limited.

Corn is 80 to 90 percent planted in this area. Many early planted fields have germinated and are near emergence. Cool nighttime temperatures have slowed emergence, but soil temperatures are now staying in the low 50s. Nitrogen rates are of interest to most growers this year with record high fertilizer prices. A trend toward sidedressing and interest in Pre-sidedress nitrate testing is showing up.

Some soybean planting has occurred with less than 30 percent of this crop planted at this time. Many growers will be finishing corn planting within a couple of days and will be able to plant soybeans at full speed. Some no-till fields are showing a lot of weed growth, especially winter annuals and perennials.

Upper Peninsula – Saturday May 6 at 1:00 PM Central time
At the Menominee MSUE office S904 US 41 Stephenson, MI 49887 in
Menominee County
Contact Mike Erdman, Menominee MSUE at 800-236-1678 or 906-753-2209.

South Central Michigan — Thursday, May 18 6 to 9 PM, MSU Livestock Pavilion.
Contact: Clinton County MSU Extension Office at 989- 224-5240

An upper troughing feature will make its way slowly eastward along the United States/Canadian border during the next few days, bringing cooler air into the Great Lakes region for the weekend. A cool front will pass across the state late Thursday night (May 4) into Friday, bringing a chance for a few light showers or sprinkles, especially across northern sections of the state. Most areas of the state will remain dry. Temperatures will slowly fall to highs Friday and Saturday ranging from in the 40s far north to the 50s south and lows in the 30s across most of the state. Mean temperatures by Saturday will remain 8 to 12 degrees below normal statewide. With expectations of clear, calm conditions this weekend (Saturday and Sunday mornings), frost and freezing temperatures will be a good possibility once again, especially in interior northern and central sections of the state.

Latest medium‑range forecast guidance suggests the gradual formation of an upper air troughing feature across the western United States with a broad ridge across the east. This type of pattern would likely bring a return of warmer and wetter than normal weather to the Midwest. The NOAA 6-10 day and 8-14 day outlooks (covering May 9-13 and 11-17) both call for mean temperatures to range from near normal levels across western sections of the state to above normal in the east and for above normal precipitation totals statewide. It is worth noting that forecaster confidence in these outlooks is considered below normal due to relatively large differences between some of the individual forecast tools used in the development of the outlooks.

In general, warmer and drier than normal conditions are forecast across large areas of the western and southern United States during the late spring and summer months. This includes the southern Great Plains region which has been plagued by drought and wildfires during the past several weeks. The outlook is vaguer for most sections of Michigan with mean temperatures for the next several months forecast to remain in the equal odds scenario of below‑, near‑, and above‑normal values. Above normal precipitation is forecast statewide during the 3‑month April‑June time frame, and across the Upper Peninsula during the May‑July period (climatology scenario elsewhere). For the mid- to late summer period, the outlook precipitation is to remain in the equal odds, climatology scenario statewide.