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| Field Crop Advisory Team Alert newsletter | |||||||
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| Vol. 23, No. 6, May 15, 2008 |
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| In this issue Insect update Insects to watch 2008 - Part IV - More on grubs in general Herbicide applications, especially micro-rates, need to be timely in sugarbeets Weeds not controlled prior to soybean emergence can reduce yield 2008 MSU Weed Tour Weather effects on preemergence corn herbicide activation Cool start to growing season affects corn Diagnosing soybean emergence problems Manganese management Wheat disease update Summer annual forage grasses for emergency crops Pesticide residue testing New core manuals available Regional reports Weather |
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Insect update
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Winter cutworm in northern Michigan |
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| Insects to watch 2008 - Part IV - More on grubs in general In the last Field CAT Alert, I noted the presence of Asiatic garden beetle grubs in many fields in St. Joseph County. In the next few weeks as corn and soybean emerges, the first indications of grub damage will be apparent. Grubs, the larvae of scarab beetles, are a growing concern in field crops in Michigan and surrounding states. Early in the season, grubs feed on germinating seeds and small plants, reducing plant stand. Later in the season, grubs feed on corn and soybean roots, reducing root mass and impacting water and nutrient uptake, and standability. Grub-feeding on root crops such as sugarbeets and potato directly impacts root size and quality. Grub identification is important because there are multiple species present in Michigan, and these species differ in life cycle and damage. Most species have a single-year (annual) life cycle, with only one generation per year, but some June beetles have a multi-year life cycle. Annual grubs stop feeding in the spring, but a field infested with June beetle may be infested for several consecutive seasons. Some grubs pupate earlier in the season (European chafer) than others (Japanese beetle). Adults of the different species also differ in behavior and damage. European chafer beetles are a nuisance around lights, but do not feed. In contrast, Japanese and Asiatic garden beetles do feed and cause damage in the adult stage. Grub Identification Most of you know by now that grub butts are important in identification. Grubs are naturally C-shaped, and it is difficult to make them lay flat. Unfortunately, important characters for identification are on the butt-end of the grub. These include the shape of the anal slit (the anal opening of the insect - usually crescent or Y-shaped) and the raster pattern (pattern of hairs and spines in front of the anal slit). The easiest way to view the anal slit and raster pattern is to cut off the end of the grub and put it upright in a dish of water or alcohol. If it is important to keep the specimen intact, set the dead grub in a small dish of fine sand (such as play-ground sand). This allows you to position the grub with the hind end facing up. Out in the field, you simply have to manhandle the grub into submission and observe its back end with a hand lens. Pictures of the four most common grubs are provided below. If you have a field with a poor stand, grubs may be the cause, particularly in fields with sandy, lighter soil. Dig up plants that remain in an open area, or at the edge of a bare area, to look for grubs or pupae. Adults may also be present under the ground prior to emergence. Remember, chafer, Japanese beetle and garden beetle are annual grubs and will pupate in May and early June. If you discover a poor stand later in the year, you may not be able to determine that grubs were the cause. Fields with a grub problem one year, often have grubs in following years. Often I attribute this to the favorable soil type, but I have also observed fields routinely infested with chafer near towns –perhaps there is spill-over of adults from neighborhood lawns into fields. Infested fields found this year should be checked next spring. Unfortunately, success controlling grubs has been spotty. Soil-applied granular insecticides provide decent control, but many no longer use these sorts of products. Most corn is now treated with a low-rate of Poncho or a similar product. Treated fields sometimes still have grub damage. Several weeks ago I visited a June beetle-infested field in Lapeer County. The grower broadcast Lorsban 15G over the worst-infested (sandy) areas, then worked it in prior to planting. Not surprisingly, the grubs were not phased by the Lorsban, but we did find grubs that appeared to be injured when he worked the soil. Sand hill cranes and other birds eat grubs, but I know there are many “crane haters” in the audience. I wonder if a grub infestation actually predisposes a field to crane colonization! This spring, several extension educators are putting in plots in Asiatic garden beetle infested fields to test treatments. Perhaps we will at least have some answers for that pest next spring.
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| Herbicide applications, especially micro-rates, need to be timely in sugarbeets This year almost 50 percent of Michigan’s sugarbeet acres are planted to Roundup Ready sugarbeets. While the timing of glyphosate (Roundup, etc.) may not be as critical for weed control as some of the strategies that we currently use i.e., micro-rates and standard splits, there is still 50 percent of the acres that are planted with conventional sugarbeets. Timely herbicide applications over these acres are critical for adequate weed control. Rain and other factors including warm temperatures can lead to delays in making a timely herbicide application, especially for micro-rate herbicide programs. Missed application timings early in the season can cause major weed problems as the season progresses. So what are some of the options that can be done to control these weeds if a micro-rate application timing is missed? Below are some general guidelines 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. Factors to consider 1) Know the size of the weeds in the field. Your decision on what to do next for weed control is primarily going to be based on weed and sugarbeet size. Weed species like common lambsquarters and velvetleaf are going to be the primary driver weeds this time of year. Five different weed control strategies are listed below that are dependent on weed size. See these different options below for each weed size (Option A, 1/8 inch tall weeds; Option B, Option C, or Option D, 1/4 inch tall weeds; and Option E, 1/2 inch tall weeds). 2) 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 sugarbeets to increased injury. This factor should be considered when deciding on what weed control strategy to use. With cool-wet conditions, both weeds and sugarbeets 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. Options Option A: Weeds are 1/8 inch tall.Even if the maximum number of GDDs has passed for your micro-rate application schedule (generally around 225 GDD34), and weeds are still less than an 1/8 inch (0.125 inch) tall, continue using a standard micro-rate herbicide program. This may be the case with some of the slower growing early summer annual weeds. 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 sugarbeet injury. Also use caution when using higher Betamix rates if sugarbeets are in the early 2-leaf stage. Sugarbeets 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 the 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. 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 sugarbeets will also be more susceptible and that could potentially lead to an increase in sugarbeet injury or stunting, especially if conditions are cool and wet. According to research that we conducted, we were able to achieve better common lambsquarters control with this strategy compared with simply increasing the Betamix rate. In our research, we shorted the interval to approximately 75 GDD which was approximately 5 days between the applications early in the season. 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 PM to reduce sugarbeet 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. This strategy was also more effective than simply increasing the Betamix rate for common lambsquarters control. 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 sugarbeets are less than the 4-true leaf stage. Weeds that are 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. In most cases, this is generally between 350 and 400 GDD. Applications of standard split rates should be made after 4:00 PM to reduce sugarbeet injury. |
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| Weeds not controlled prior to soybean emergence can reduce yield Driving around the state, I have noticed several no-till fields that still have carpets of winter annual and some newly emerged early summer annual weeds, like common lambsquarters and giant ragweed. With soybean planting in full swing, it is extremely important that these weeds be controlled prior to soybean emergence. Ideally, these weeds should have been controlled prior to planting, but because many of these fields have already been planted it is important to control these weeds prior to soybean emergence. Timely burndown herbicide applications in no-till soybean fields are critical to protecting soybean yield. Over the last several years, there has been the tendency for growers to plant their soybeans 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 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 percent (8.3 bu) (Figure 1). This reduction in yield can lead to as much as a $107.90/A loss in revenue at the end of the season with current soybean prices ($13.00). There is also some thought that these mats of winter annual weeds can serve as hosts for early-season insect pests that can then transfer over to soybeans once they emerge. Remember early control of these weeds is important. If a burndown herbicide application cannot 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 2008 Weed Control Guide for Field Crops (E-434). Remember with some of these treatments, especially treatments that contain 2,4-D ester (1 pt/A) there needs to be a minimum of seven days before soybeans can be planting. See comments and label precautions on the safety of applying certain burndown herbicide treatments after soybeans have been planted. |
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| 2008 MSU Weed Tour We invite you to make plans to attend the annual Michigan State University Weed Tour, on Wednesday, July 2 beginning at the MSU Botany Field Lab (located on College Road, north of Jolly Road). Registration begins at 9:00 AM with the field tour kicking off at 9:30 AM. The tour will provide ample opportunity to look at research plots and participate in some short field presentations. (Be sure to bring a hat and sun screen.) Participants can compare their favorite corn and soybean herbicide programs to other commercial programs and evaluate how new transgenic crops interact with weed management strategies. The morning tour ends with lunch. The afternoon tour will begin at 1:00 PM at the MSU Horticulture Farm (College Road, south of Jolly Road) and will include weed control research in horticultural crops. Pre-registration for the tour is $25 per person which includes a tour booklet and a lunch ticket. A flier with a map and registration form is enclosed in this issue and is also available online at www.msuweeds.com, or can be obtained by contacting Deb Misiak at 517-355-0271 ext. 1112, email: misiak@msu.edu. |
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| Weather effects on preemergence corn herbicide activation As discussed in a previous Field CAT Alert article, preemergence herbicides should be applied as soon after planting as possible because delayed application increases the risk of poor herbicide performance, especially for grass control. Delayed preemergence applications were covered in detail, but what if you are able to make your preemergence application and the weather is cold, or extremely wet or dry after planting? An activating rainfall is required after preemergence herbicides are applied. This rainfall stimulates seed germination exposing the seedling to the herbicide in the soil. The herbicides in turn are activated by the rainfall, which helps to incorporate the herbicide into the soil and aids in the uptake into the weed roots or shoots. Soil moisture is an important component to ensure herbicide activity and seed germination, however, temperature is also a key factor. If there was good moisture at planting and the time of your preemergence application, but no appreciable rainfall within a week or two, weed seeds can germinate and potentially grow through the herbicide sitting at the soil surface. Conversely, if cool wet weather occurs after planting, weed seeds may not germinate as quickly as they would under warm conditions. This can lead to a delay in germination that occurs after preemergence herbicides have been activated or after they have dissipated in the soil. Although a good rainfall is essential, a heavy rainfall, or extended wet weather, can lead to the herbicides being carried below the weed seed germination zone or hydrolysis of the herbicide. These situations can lead to a shortened period of preemergence weed control and the need for postemergence weed management. Weeds that emerge from wet soil in dry weather may be controlled if rainfall occurs soon after weed emergence; however it is more common that a postemergence application will be needed to control the emerged weeds. The upside of this situation is that when rainfall does occur subsequent flushes of weeds will usually be controlled. However, when weeds emerge after the preemergence herbicides have been dissipated in the soil, the only option is postemergence weed control. In situations where the soil is dry enough, rotary hoeing will control small weeds. Delaying your postemergence herbicide application as long as possible will allow you to control your emerged weeds and potentially avoid a second postemergence application. Keep in mind that research at MSU has shown that it is necessary to control weeds before they reach four inches of growth to prevent measurable yield reduction. Also be aware of the products applied preemergence when selecting postemergence applications, especially when products containing atrazine or Callisto are applied preemergence. Atrazine should only be applied postemergence in a premix or for emergency use due to critical timing and rate or carryover concerns. Callisto, Camix, Lexar, or Lumax cannot be applied postemergence where one of these products was applied preemergence due to rate restrictions and subsequent carryover concerns. Herbicide options for postemergence weed control are often dependent on the hybrid planted in the field. Many postemergence herbicides can be used on any corn hybrid, while others such as Liberty and glyphosate require herbicide resistant hybrids. For details on postemergence herbicides programs in corn, see 2008 Weed Control Guide for Field Crops, Extension Bulletin E-434. Another issue to consider with cool, wet weather and preemergence herbicides in the spring is crop injury. Preemergence herbicide selectivity is primarily through differential metabolism—meaning that crops are able to break down the herbicide more rapidly than weeds, thus the weeds are killed, but crops survive the effects of the herbicide. Cold soil temperatures can lead to crops under stress that are less efficient at metabolizing herbicides and are prone to injury. For the same reasons moisture is good for weed control, the potential for crop injury will increase with soil moisture content since more herbicide is available for absorption in wet soils. Where delayed preemergence application with amide, amide: atrazine premixes, or other products are planned as discussed in the last Field CAT Alert article (May 8, 2008), patience should be exercised where conditions are cool and wet. While these products are labeled for this use, there will be an increased risk of injury due to stressed corn, and delayed preemergence applications should be postponed if possible until conditions have improved and the corn has begun to recover. The same precaution is true when applying postemergence herbicides after prolonged periods of cool weather. If there is ever a question, check the herbicide label or contact your extension personnel. |
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| Cool start to growing season affects corn The cool, early May temperatures have resulted in significant variability in corn emergence across fields. Ideally, we would like to see all corn plants emerge simultaneously to minimize plant to plant competitive advantages and maximize yield potential. Under marginal conditions of cool weather within field spatial variability conditions are exacerbated. Areas with darker soils and more well drained soils warm up quicker and, conversely, poorly drained areas and areas with heavy residue take longer to warm up. The large disparity in soil temperatures drives the disparity in corn seedling emergence. Additionally, if the cool temperatures continue, we will likely see symptoms of yellow and purple corn. The pale yellow color is symptomatic of low photosynthetic activity and general nutrient stress experienced by the plant. Similarly, poor root growth can result in purple-colored corn. Many factors contribute to the symptom of yellow corn seedlings. Sunlight drives the photosynthetic process and a lack of heat units results in slow seedling growth. Cool spring temperatures combined with saturated soil also limit corn seedling root growth and penetration into the soil. This confounds the slow growth of the corn plant by limiting nutrient uptake. Furthermore, the mineralization and plant availability of nutrients including nitrogen and sulfur is slowed down due to slower microbial activity in cool wet soils. These same conditions can also result in purple-colored corn. The restricted root growth resulting from the saturated soils can cause a build up of sugars in the corn leaf. These sugars would normally be used for root growth, but when accumulated in the leaf, result in the production of anthocyanins, which give the leaf a purple color. In addition, some corn varieties have inherently higher levels of anthocyanins. If the purple color persists after field moisture conditions normalize, the discoloring may be indicative of other root related problems such as a compaction problem or a phosphorus deficiency in the soil. Cool wet soils and weakened plants also set the stage for fungal and bacterial root disease in corn. In addition, weather-stressed corn is more susceptible to herbicide injury, which can also result in yellowing. Finally, weakened plants are more susceptible to damage from insects. Scouting for disease and insect pests is especially important in weather-stressed fields of corn. The good news is that corn will generally overcome these early season stresses with a good dose of warmer weather. Continue to monitor nutrient levels, particularly nitrogen. Once the weather turns, most of the corn will likely outgrow early season discoloration symptoms |
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| Diagnosing soybean emergence problems Early detection and diagnosis of soybean emergence problems is always important to achieving high yields. However, early season-scouting is even more important this year due to a reduction in seed quality. Soybean emergence ranges from six days under ideal conditions to 14 days under more challenging soil conditions. Conditions that can lead to delayed or uneven emergence include: cold soil temperatures, excess soil moisture, inadequate soil moisture, soil crusting, improper seeding depth or uniformity, poor seed-to-soil contact, insect feeding and disease infestations. If slow or uneven emergence occurs, dig up the plants and inspect them for signs of disease or insect damage to the root, hypocotyl or cotelydons. In most fields, the major insect pests affecting seedling emergence are seedcorn maggots, white grubs and wireworms. If seedcorn maggots have reduced the stand to an unacceptable level, replanting should correct the problem as the decaying organic material that lured the adults to the field should no longer be as attractive. If wireworms or white grubs are responsible for unacceptable stands, the seed will need to be treated with Cruiser prior to replanting. Phytophthora, Pythium, Rhizoctonia and Fusarium are the soil-borne diseases most likely to damage germinating soybean seed. Fusarium spp. are present over a wide range of temperatures and may not kill seed outright, but may cause stunting and root rots later on. Pythium is more likely to create problems under cool, wet soil conditions. Pythium is prevalent in southwest Michigan soils and damage is likely to occur when a heavy rain occurs within 24 hours of planting. Affected plants will have swollen and bent hypocotyls. Replanting when the soil temperatures exceed 60ºF should result in satisfactory emergence. Warmer temperatures and drier conditions favor Rhizoctonia (75-89°F). Phytophthora is favored by poorly drained soils and warmer temperatures (68-77°F). If seedlings emerged from the soil but died quickly, Phytophthora is a likely suspect. Replant with resistant varieties or fungicide-treated seed. If no insect feeding or disease symptoms/lesions are present, determine if the surface of the soil has developed a crust. If a crust exists, consider using a rotary hoe to break up the crust. To prevent damage to emerging seedlings, avoid rotary hoeing when the plants are in the "crook" stage and for three days after this brittle stage occurs. Large soybean seed is more likely to experience emergence problems in crusted soils than small soybean seed due to their larger cotelydons. If crusting is not the problem, determine if the planting depth is correct and uniform and check to see that soil is firmed around the seeds. Some varieties may not emerge well when planted at depths of 2 inches or more. If no planting problems are detected, and the seeds/seedlings look healthy, inadequate soil moisture is likely the cause of the delayed emergence. Wait until a rain occurs and recheck the field. When deciding if replanting is warranted, always compare the yield potential of the existing stand to that of the replanted stand and account for all replanting costs. Consider the following information: yield losses of 0.6 of a bushel per acre per day have been shown to occur when planting is delayed after mid-May, a uniform stand of 100,000 plants per acre will produce good yields and seed supplies are short this year, so seed from high-yielding varieties may not be available. |
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| Manganese management Manganese (Mn) is one of the more challenging micronutrients to manage and is the one most likely to be deficient on many field crops. MSU Extension bulletin E-486 is an excellent resource for information on manganese and the other secondary and micronutrients. The field crops most likely to show Mn deficiency are dry beans, soybeans, sugarbeet, wheat and oats. Manganese is characterized by a drab olive-green appearance of the crop with leaves of broadleaves showing yellowing between the green veins. Leaves of corn and the cereal grains show a yellowish striping. With more severe deficiency on wheat and oats, the yellow strips become more diffuse and the leaves more yellow. Deficiencies are most likely to occur on old lake bed soils, high organic matter soils, soils with pH above 6.5 and acid soils that have been limed up to near 6.5. Manganese deficiency is also more likely to occur under dry soil conditions than moist soil conditions. Soil application of Mn is of limited benefit because it readily reacts with the soil and is bound in slowly available forms. Broadcasting Mn is a waste of money. Including Mn in band fertilizer (1-2 lbs/a) does provide Mn during the early growth stages. However, sometimes even when Mn is supplied in the starter fertilizer, it is necessary to spray the foliage with Mn to fully prevent or correct a deficiency. Application rate is very important. When spraying Mn, be sure to supply near 1 lb actual Mn per acre. Last year in one Mn deficient soybean field only 0.5 lb Mn per acre was applied and the soybeans still showed Mn deficiency except where there was spray overlap. There the soybeans were a good, green color. Since Mn has limited mobility in the plant, a second application may sometimes be necessary to cover new growth and fully correct a deficiency. Recently, there have been some reports of possible Mn deficiency in wheat. This may be partially due to the somewhat dry soil conditions that have existed during April in some areas. When spraying Mn to correct a deficiency, apply 1 lb actual Mn per acre. Spraying Mn during the early growth stages will be more likely to improve subsequent growth and yield. Including some Mn with fungicide sprays may help, but is probably too late to be of major benefit. |
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| Wheat disease update Disease-wise, it has been pretty quiet so far this season. I diagnosed leaf rust on one sample of Caledonia white wheat from Oceana County this week. It was on only the lowest leaves, and appeared as if it may have overwintered. There was plenty of snow cover this winter to protect the rust fungus. It had not started to move up the leaves, and no fungicide application was needed. A little powdery mildew is beginning to appear now low on the plants in early planted fields that are particularly lush-growing, but so far it has stayed low in the canopy. Temperatures expected for the next week or so are highs in the 50’s to 60’s and lows in the 30’s in the north and 40’s-50’s in the south with at least some chance of rain most days. It appears that daytime temperatures may be favorable for several diseases, but it may be a little cool for them at night. Favorable weather conditions for powdery mildew are temperatures of 59-72°F and high humidity. The threshold for powdery mildew is two to three spots per leaf (on the leaf just below the flag leaf ) averaged over 30 to 50 randomly selected leaves in the field. Temperatures of about 50-68°F along with windy, wet conditions favor development of Septoria leaf spot. The threshold for Septoria leaf spot is one to two lesions per leaf (on the leaf just below the flag leaf ) averaged over 30 to 50 randomly selected leaves in the field. An assessment of disease levels at flag leaf or shortly before allows for a timely application of fungicide if thresholds have been reached. Fungicides containing strobilurins (Stratego, Quilt, Headline, Quadris) are not recommended once wheat has reached boot stage- heading as DON (vomitoxin) levels may increase if conditions are favorable for fusarium head blight later on. Very little disease has shown up on wheat foliage so far, and no fungicide applications have been needed for early season diseases. I have heard that a lot of fungicide tank mixed with herbicide was applied to wheat at full tillering (Feekes 5) as an insurance policy. Granted, applying fungicide along with herbicide at Feekes 5 does save a trip over the field, there is still the added expense of the fungicide. Most university based-research so far has not supported the contention that an early season fungicide application contributes to increased yield. The only exception I have read about has been to control tan spot on spring wheat planted into wheat stubble in the states further west. Tan spot rarely shows up Michigan as a disease problem. My wheat trials this year include several commonly used fungicides applied at Feekes 5. We’ll see how they compare to other treatments in terms of disease, yield and quality. Growers who take the time to scout their fields for foliar diseases and determine whether thresholds have been reached before making the decision to apply a fungicide will profit the most in terms of both yield and controlling input costs. Foliar diseases can adversely affect yields and quality if they are present at economic levels, but applying fungicides does not increase yield. It only protects the yield potential that is already there. |
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Summer annual forage grasses for emergency crops |
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| Teff Teff, Eragrostis tef (Zucc.) Trotter, is a warm season annual grass native to Ethiopia(see figure 1 ). It is adapted to environments ranging from drought-stressed to waterlogged soil conditions. The seeds are extremely tiny, containing about 1.25 million seeds per pound. Despite its small seed size, teff is an aggressive competitor once established. In its native habitat maximum production occurs with a growing season rainfall of 17 to 22 inches and a temperature range of 50 to 85°F. Teff can be used as a livestock forage or pasture crop, and is primarily grown in Africa, India, Australia and South America. In the United States, teff is grown on limited acres in the Pacific Northwest and Midwest. Teff is a warm season annual grass which has shown good promise as an emergency forage crop in New York. Recent research from the Oregon State University Klamath Experiment Station and the Cornell Cooperative Extension Associations of Jefferson, St. Lawrence and Rensselaer Counties indicate good promise for teff as a forage crop. Our teff demonstration planted in East Lansing in early July 2007 resulted in a dry matter yield of over 5 tons per acre dry matter with three cuttings. The forage quality of the hay showed crude protein of 15%.Seed of teff is available through many farm seed dealers in Michigan this spring. We will be evaluating teff in research trials in Michigan this summer comparing it to other warm season annual grasses and determining nitrogen application timing, and forage quality. |
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Forage sorghum Utilization of Summer Annuals
A firm, well-prepared seed bed is needed for good seed-soil contact and rapid germination. Conventional, minimum, or no-till drilling can be used for establishment. Date of seeding Sudangrass and sorghum are warm-season grasses. Seed should be planted into soils when average soil temperature is above 60°F. Plan the seeding date to produce desirable feed when needed. Stagger planting dates to aid rotational grazing. It takes at least six weeks after planting before usable forage is available. Later plantings will result in lower yields due to summer droughts and fall frosts. Planting rates Recommended planting rates depend on row spacing. Broadcast and narrow-row spacing are preferred for sudangrass and sorghum-sudangrass hybrids because they result in shorter plants with finer stems. Total forage yield will be similar for different row spacing because sorghums and sudangrasses tiller. Removing the primary growing point at the first cutting enhances tillering. First-cut yields are usually higher for broadcast or narrow-row seedings than for 20- 40 inch rows. If planting with a grain drill, plant 15 to 20 lbs/acre seed of pearl, German, Japanese or Siberian millet. Forage sorghums should be planted at 12-15 lbs/acre with a grain drill. Use 6-12 lbs/acre for pearl millet. Sudangrass and sorghum-sudangrass are seeded at 20-30 lbs/acre in 7 inch rows with a grain drill. Higher seeding rates help in producing finer stems, which is desirable for grazing and hay. Planting depth Seed to a depth of 1-2 inches, depending on soil moisture conditions. Seeds planted too deep do not emerge well and poor stands may result. Fertilization Summer annual grasses have fertilizer requirements similar to those of corn. With rapid growth, apply sufficient nitrogen at planting to ensure establishment and high first-cutting or grazing yields. Apply 40-80 pounds of nitrogen per acre at planting and an additional 50 pounds after the first cutting or grazing. Phosphorus and Potassium should be applied based upon soil test recommendations. Prussic acid poisoning Cellular damage to sorghums and sudangrasses from frost, wilting, bruising, drought, excessive soil nitrogen, or deficiencies in soil phosphorus or potassium can result in prussic acid poisoning in cattle. Prussic acid poisoning consists of the following sequence of events: plant cells rupture and cyanic acid (HCN) forms from cyanogenic glycosides; cattle consume forage with elevated HCN levels; HCN is absorbed from the rumen; HCN binds to hemoglobin; asphyxiation and death occur. Poisoning is most likely after a frost when animals consume the leafy regrowth. Regardless of season, plants less than 18-24 inches tall should not be grazed. Suspect forage should be harvested as dry hay or silage. Both harvest methods tend to reduce hydrocyanic acid levels. Nitrate poisoning High dietary nitrate levels can overload the animal’s ability to detoxify this chemical and can result in death due to asphyxiation. In the rumen, nitrate is reduced to ammonia, which is absorbed into the bloodstream or converted into microbial protein. High dietary nitrate levels that overload this microbial reduction system cause an accumulation of nitrite in the rumen. This nitrite is then absorbed into the bloodstream where it binds to hemoglobin in place of oxygen. This deprives the tissues of oxygen and causes abortions and asphyxiation. Sorghums and sudangrasses can accumulate high levels of nitrate during environmental conditions that decrease plant growth rate, including water stress, lack of sunshine and high nitrogen fertilization. Plants usually absorb nitrogen as nitrates and synthesize protein. However, during stress, the synthesis rates decrease and nitrates accumulate. Cattle should not be fed forages with nitrate levels greater than 2 percent. Nitrate analysis can be obtained from numerous commercial laboratories. Seed availability Most commercial suppliers of seed carry varieties of sorghums, sudangrasses, BMR sudangrass, hybrid-sudangrasses, and sorghum-sudangrass hybrids, Sorghum-sudangrass BMR, and millets. Check with your local supplier for availability and variety characteristics. Because of low hay carryover from last year’s crop, there will be higher demand for annual forage crops. Michigan State University does not routinely test varieties of annual grasses and therefore does not provide variety recommendations. |
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| Pesticide residue testing Herbicides can injure desirable, non-target plants in a variety of ways, including drift, volatilization, carryover, tank contamination, misapplication or simply accidental or intentional exposure. In addition to diagnosing plant pathogens, nematodes and insect-related pests, all plant samples submitted to MSU Diagnostic Services – the multi-disciplinary plant health and pest diagnostic facility on campus – are visually inspected for pesticide injury. If warranted, samples can be tested for the presence of pesticide residue using appropriate analytical instruments and techniques. Sampling We urge clients that are interested in pesticide residue testing to contact the laboratory before collecting and submitting samples. Samples should be collected immediately if pesticide injury is suspected. If you suspect a drift event has occurred but are not positive, it may be wise to collect a tissue sample that day or the next and place the sample in the freezer. Glyphosate and 2,4-D, for example, can be very difficult to detect and quantify in the tissue once injury symptoms develop. Therefore, a little foresight in sampling may really help if injury symptoms do develop 7 to 10 days later. Collect enough plant tissue to fill a quart-size plastic bag; collect enough soil to fill a pint-size plastic bag. In general, samples should be frozen immediately and kept frozen until arrival at the laboratory. Fees Plant samples are visually inspected for pesticide injury for $20. Samples can be tested for pesticide residue on an individual basis or, if available, in multi-pesticide screens. Fees may vary depending upon number of samples, clientele location and numerous other special circumstances. Fees for individual pesticide residue screens are generally $90, $100 and $125 in water, tissue and soil, respectively. Fees for multi-pesticide residue screens are generally $125, $150 and $175 in water, tissue and soil, respectively. Questions regarding pesticide injury or pesticide residue testing should be directed to Steven Gower by phone at 517-432-9693 or email at sgower@msu.edu. |
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| New core manuals available Completely rewritten commercial and private certification core manuals are now available from Michigan State University (MSU) Extension. The manual for private pesticide applicators (Extension Bulletin E3007) includes the National Pesticide Applicator Certification Core Manual and the Michigan Private Core Manual Addendum. The commercial manual (Extension Bulletin E3008) consists of the National Pesticide Applicator Certification Core Manual and the Michigan Commercial Core Manual Addendum. Including the National Pesticide Applicator Certification Core Manual facilitates reciprocity between states, making it more likely that state regulatory agencies will recognize the credentials of certified applicators working in other states. The national core manual discusses federal pesticide laws and the Michigan-specific addendums add the state of Michigan pesticide laws and regulations. The private applicator addendum also includes private applicator equipment and calibration information. The new manuals are better organized, illustrated, easier to read and more comprehensive than past editions. They also contain more recent information on regulations and pesticide safety recommendations. These manuals are used to study for the initial and renewal certification exams offered by the Michigan Department of Agriculture. After passing the exams, an individual becomes a certified applicator and can purchase restricted-use pesticides. Applicators must renew their certification every three years by retaking the exams or by attending enough MDA-approved seminars to earn credits toward renewal. Each manual is available for $30 from MSU Bulletin Distribution Center or any county MSU Extension office. To find an office near you, visit www.msue.msu.edu. |
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Regional reports Weather has been unsettled with a nice, gentle all day rain of 1.5 inches falling on Mother’s Day, May 11, and another half-inch yesterday. Neither the air nor soil temperatures have been increasing much this month, so germination has been slow. Crop report Alfalfa is growing very well with most stands 15 to 18 inches tall. Annual weeds have had a slow start also, so most fields will have better quality than most year’s first cuttings. Alfalfa weevil feeding continues, but not at threshold levels. No potato leafhoppers yet. First cutting should come off as soon as the weather permits, which is questionable for the next ten days. Corn is mostly planted and has generally emerged and is green. Rains have helped germination and emergence. Advanced fields are at the V2 growth stage. Most fields are very clean. Soybeans are perhaps 75 percent planted though few fields have emerged. There is more tillage in these fields than in recent years. Wheat growth has zoomed to Feekes’ stage 8 with advanced fields already at stage 9. There are fields still at Feekes’ stage 6 and 7, however. With the forecast for off-and-on rainy weather for the next ten days, I expect diseases to increase and lots of fungicide spraying to begin. There is lots of pressure by the chemical companies to protect and even increase yields by applying fungicides and insecticides. Nitrogen skips are apparent. Miscellaneous Farmers have generally caught up with recent years’ planting progress. |
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2 -- Southwest Crop report A good deal of the commercial corn had been planted in the areas where seed corn production dominates the cropping patterns. St. Joseph County may have been as high as 95 percent planted by last weekend. Cass and Branch counties were also making very good progress in commercial corn. Places where soils are heavier, or where the temperatures have been cooler along the lake, have significantly less planting progress. Early emerged corn is yellowed, but stands are looking pretty good, especially on lighter soils. We may be just a tad behind in getting corn fields sprayed with herbicides, and many fields may be receiving pre-emergence herbicides early post emergence. There is little evidence of damage from black cutworms or other pests in the few fields that I have walked this last week. Seed corn planting was progressing well before last weekend. Many of the early fields have both the male and female inbreds planted. The cooler soil temperatures are keeping seed corn field staff busy looking at germination progress to decide proper delay in planting either the male or female inbreds to insure that pollen shed will occur when the silks are viable. Rainfall in St. Joseph County was not heavy enough to significantly impede planting progress at this point. Warm, dry weather, however, would be appreciated by all. Soybean planting progress is better in St. Joseph and Branch counties than in may other places in the southwest region. Early planted soybeans have emerged and are looking ok, at this time. The majority of the soybeans planted recently have not emerged. Some are beginning to show crooks. For soybeans planted in areas where there was heavy cover crop growth or winter annual weeds, it may be wise to keep an eye on potential damage from black cutworms. There were a few larvae found in fields that had lots of green materials when I walked the fields a week ago looking for white grubs. Winter wheat continues to look pretty good across the region, with development ranging from Feeke’s stage 9 back to Feekes stage 8. Most stands have few weed problems, and the fields do seem to be growing well with the cooler temperatures. Nitrogen applications seem to have kept most fields fairly dark green. You can find some powdery mildew very low on the canopy, and the lesions are few at this point. With cooler and wetter than normal conditions in the forecast, it may be a good idea to keep an eye on fields to monitor for progression of fungal leaf disease lesions on the upper plant leaves. Alfalfa has continued to recover from the frost damage that could be seen following the extreme low temperatures on April 30. Fields are 12 to 14 inches in height, or more. Alfalfa weevil larvae are small, but quite numerous in many fields across the lower portion of the region. The worst fields I have seen have been in Western Van Buren County, where tip feeding was definitely above the threshold level of 40 percent tip feeding. MSUE ANR educator Mike Staton indicated that he saw much the same situation in other places in Van Buren/Berrien counties. Base 41 GDD accumulations for select weather stations in Southwest Michigan are: Kalamazoo 532, Battle Creek 551, Niles 507, Allegan 493 and Coldwater 464. Dairy growers often start cutting alfalfa at 750 Base 41 GDD’s to achieve top hay production and quality. Based on these GDD accumulations and the forecast, we may be 10 days or more away from this target in much of the region. While alfalfa weevil larvae develop more slowly with cold temperatures, tip feeding will likely continue to occur. Insecticide applications are more likely to be cost effective if tip feeding is approaching 40 percent, and the alfalfa is 7-10 days away from harvest. |
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3 -- West Central A generally dry week has allowed much planting progress to occur over the region. Rain showers on May 14 have slowed field work a bit across the region with 0.1 to 0.75 of an inch of rain received. High temperatures have been in the upper 50s to mid-60s. Low air temperatures have been in the 30s and 40s. Frost was observed over much of the area this morning. Low soil temperatures have been in the upper 40s to mid-50s. Crop report Alfalfa growth is progressing well with many stands at 10 to 12 inches in height. Frost damage has been light for the most part. Very little alfalfa weevil damage has been observed. Grasses are 12 to 16 inches. Growing degree day base 41 (GDD 41) are 450-500 at weather stations around the area. Pastures are starting to grow fast. Rotations should be quick to try and stay a head for best quality forage. Approximately 70-80 percent of the corn crop is planted. Early planted fields are at V1. Thirty to 40 percent of the soybean crop has been planted with few fields emerged. Wheat is in growth stage Feeke's 6-8 with the majority in 7. Very few fields are still getting first applications of nitrogen. Late applications of 28 percent UAN solutions are very risky as the flag leaf will be exposed to injury . Disease pressure remains low. Oats are emerging with good stands. Rye varies in development from Feeke’s stage 8 to boot. |
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4 -- Central Cool weather prevailed over the past week. Soil temperatures remain cool, slowing germination and emergence of planted crops. There were scattered showers over the region on Wednesday, May 14 with variable amounts ranging from a trace to over a half inch. Planting progressed across the region where field conditions allow. Some farmers are nearly finished planting, while some are just starting. Crop report The corn crop is about 80 percent planted. Farmers are trying to wrap up planting as field conditions allow. The early planted fields have emerged and look pretty good considering the cool temperatures. Some areas of the region have crusting issues, and the rains on Wednesday should soften the soil and allow emergence. No reported problems at this time. Soybeans are about 50 percent planted across the region. The early planted beans are beginning to emerge. Planting is progressing as fields dry out. Wheat is in Feeke’s 7-8 with very little disease present in most fields. There are small amounts of powdery mildew in some fields, but it remains low in the plant. Wheat growers are advised to scout fields regularly for disease problems and monitor growth stage. It is critical to know what growth stage your wheat is in and disease pressure if you are considering making a fungicide application. Alfalfa is really benefiting from the cooler weather and is looking very good. We had virtually no winter injury. Most alfalfa is 14-16 inches. There have been no reports of alfalfa weevil feeding at this time. Farmers are encouraged to scout for this pest. If you use growing degree days to time first cutting, as of Thursday morning, Isabella County is at 437 base 42. New alfalfa seedings are looking very good. Oats are enjoying the cool weather and look very good. The alfalfa seeding in the oats are doing very well. |
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5 -- Thumb Some much welcome rain fell on Mother’s Day, May 11, with about 0.3 inch accumulation and more reported to the south. About 0.4 accumulation fell during the day of May 14. We woke up this morning, May 15, with some light frost. Warmer temperatures would be helpful to keep things rolling. Crop report Wheat continues, for the most part, to look good. We are at Feeke’s stage 6 to 7 with not much disease pressure. Alfalfa growth is good, but variable depending on the age of the stand and fertility level with most between 15 to 20 inches. Many have completed corn planting with some waiting for final manure applications. Emerged corn is up to growth stage V2. Emergence and color look good. Sugarbeets are for the most part emerged. Dry soils caused some emergence concern. Weed size in some fields is a concern. There is some insect feeding on the cotyledons, but it is probably nothing of concern. Soybean planting is complete for some, and nearing completion for others. Most fields are not yet emerged. |
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| Weather news Jeff Andresen Agricultural Meteorology Geography A significant change in the upper air pattern across North America is expected during the next few days with the formation of a deep troughing feature across the Great Lakes region by this coming weekend. This pattern is expected to continue for much of the next one to two weeks and should lead to cool and cloudy conditions this weekend and much of next week. In the short term, high pressure across the region on Thursday, May 15 will give way to a weak area of low pressure and accompanying cold front approaching the state from the northwest Friday. This weather system will bring a good chance for showers statewide by late Friday continuing through much of the weekend. Rainfall totals through early next week are expected to remain on the light-moderate side with most totals in the 0.25-0.5 inch range. High temperatures during the next several days will generally remain in a range from the mid-50's north to mid-60's south with lows ranging from the upper 30's to the low or mid-40's. While most nights during the next week are expected to be cloudy and with some wind, it is important to note that with relatively cold expected aloft, frost and freezing temperatures are a possibility on any given night should clear, calm conditions develop. This would be especially true on low-lying areas such as muck soils where cold air tends to pond at night. In the medium‑range forecast period, outlooks for the Great Lakes region are dominated by the upper air pattern mentioned above, with more cloudy and cool weather expected. Not surprisingly, both 6-10 day and 8-14 day outlooks covering May 20-24 and May 22-30 call for below normal temperatures. Precipitation totals during both time frames are forecast to range from below normal levels across northwestern sections of the state to below normal levels in the southeast. Enviro-weather update We are happy to report that six new automated weather stations have recently been added to the Enviro-weather network: Arlene, Berrien Springs, Coldwater, Hickory Corners (MSU Kellogg Biological Station), Keeler and Romeo. Many thanks to the sponsors of these sites and to local MSU Extension personnel for making this possible. On a related note, a new option is now available for downloading automated weather station data. Users may choose to download data in Comma Separated Value (CSV) format, which makes the transfer of data to spreadsheet-oriented software such as Microsoft Excel much easier. To use the new feature, go to the Michigan Automated Weather Network site at http://www.agweather.geo.msu.edu/mawn/ and select a station of interest. Next choose the Custom Reports (Data‑on‑Demand) function. Select your preference of data type: daily, hourly, or five minute data (this feature will also be available for growing degree day totals within the next week or so). Finally, select your data output format in either ASCII/HTML (the only previous option) or CSV (comma‑delimited), which is the new option. |
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