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| Field Crop Advisory Team Alert newsletter | |||||||
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| Vol. 23, No. 4, May 1st, 2008 |
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| In this issue Insects to watch 2008 - Part III - soybean aphid S-B-A and K... what's the link? Weed control in soybeans can benefit from preemergence soil-applied herbicides Delayed preemergence and early postemergence herbicide applications in corn Allocating fertilizer resources for crop production Managing higher priced fertilizer inputs Fusarium head blight risk assessment models and DON prediction model Regional reports Weather Next issue May 8 |
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| Insects to watch 2008 - Part III - soybean aphid Last season was a banner year for worms and beetles, but where were the soybean aphids? Chris DiFonzo, the self-proclaimed soybean aphid queen (that’s me) predicted an aphid outbreak for 2007. Where was the outbreak? Will the prediction for 2008 be equally as accurate? Let’s recap the 2007 season. In the winter of that year, entomologists in the Midwest predicted a soybean outbreak. That prediction was based on two lines of evidence: suction traps and egg numbers. The Northcentral Aphid Suction Trap network consists of over 40 traps in 10 states, running in the summer and fall. Fall catches of soybean aphid are important because they consist of winged males and females leaving soybean for buckthorn, the overwintering host. The females land on buckthorn and have daughters; the daughters mate with the males (in human terms, mating with their uncles), and lay eggs. The egg stage allows soybean aphids to survive the cold northern winters. In general, a large fall flight predicts an aphid outbreak the following year, in this way: Large fall flight of soybean aphid leads to… |
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| At the end of 2006, dozens to hundreds of winged soybean aphids were captured in the suction trap network (Table 1), The numbers may not seem high, but remember the trap is a vertical PVC pipe drawing in air 25-30 feet above ground. It is sampling a small amount of air overall, so the trap catch is a tiny fraction of the aphids actually flying from soybean to buckthorn. In the winter of 2006-07, entomologists sampled buckthorn for soybean eggs. Eggs were found at numerous locations, hundreds on branches at some locations. Again, this may not seem very impressive, but aphid eggs are very small and generally difficult to find. Finding eggs at all, much less multiple eggs on a bud or branch, is significant. Because of the fall suction trap counts and egg numbers, we predicted an outbreak. A spring freeze in April damaged buckthorn buds across the Midwest. In central Michigan, buckthorn shrubs growing along the edge of wood lots or the road were severely hit, and the damaged branches did not leaf out quickly, and did not support soybean aphids. However, many buckthorn shrubs further back from the edge were not damaged, and leafed out normally. Thus the aphid population was probably “dinged” a bit, but not knocked out. In Michigan, aphids colonized soybean fields as normal, beginning in early June. By mid-June, fields in the Frankenmuth area were over threshold, reminiscent of the early aphid infestation in southwest Michigan in 2005 – our last big outbreak year. Only fields planted early (in April) went over threshold; May-planted fields emerged later and missed the aphid flight that colonized the April fields. Early-planted fields in Ontario also went over threshold. The over-threshold fields were treated, and predators and parasitic wasps attacked the survivors. Aphid numbers increased slowly until early July. Then unseasonably hot weather and minimal canopy resulted in very hot temperatures at the soil surface. In research plots, the ground was too hot to sit on. That same week, the building aphid numbers took a dive. Soybean aphids can survive hot weather when they are under a cool plant canopy, but they likely cannot tolerate 90-degree days when plants are still small. The population growth rate appeared to slow, and perhaps predators had a chance to catch up. Fields were essentially aphid-free until August, until winged aphids blew in from surrounding states. Some fields went over threshold, but for most fields it was too late to build aphid populations. Surrounding states, northern Indiana and the Toledo, Ohio area, had a similar experience to Michigan. An outbreak was predicted, but did not materialize. In contrast, many other states did have their predicted “aphid year.” From Quebec to the Dakotas, millions of acres were treated for soybean aphid. Michigan didn’t have an outbreak, but many other states did. We were the hole in the outbreak donut, so to speak. What about 2008? Table 1 shows that the suction trap catches in the fall of 2007 were considerably lower than at the same locations in 2006, with one exception, Michigan. A couple of traps did catch aphid moving out of soybean to buckthorn. That makes some sense, because 2007 was essentially a non-outbreak year for Michigan, and low years tend to be followed by outbreak years. However, I have not found any eggs this winter on buckthorn. Across the Midwest, a low aphid year is expected in 2008, but Michigan is more of a mixed bag. We may see some pockets of infestation if certain locations have high egg numbers. The key is to scout fields to catch these potential infestations before they go over threshold. Table 1. Soybean aphid suction trap catch in 2006 and 2007
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S-B-A and K….what’s the link?
Hypothesis #1: Soybean aphid numbers are higher on K-deficient plant Answer: Yes. In commercial fields, the average number of aphids per leaf was 50 percent greater on the plants with severe yellowing compared to plants growing in green areas of the same field. Plants from deficient and non-deficient areas had the same aphid number per plant. However, the K-deficient plants were stunted and had fewer leaves per plant, so that aphid density was higher. This is why aphids appeared to “drip off” of symptomatic plants. Hypothesis #2: Soybean aphid populations increase faster on K-deficient plants Answer: Yes. In field cages infested with soybean aphids on June 1, populations went over the economic threshold and injury level (EIL) earlier, and increased to a much higher level, on plants growing in unfertilized plots (dashed line) compared to plants growing in K-fertilized plots (solid line). (View accompanying graph.)
Hypothesis #3: Soybean aphids reproduce faster on K-deficient plants Answer: Yes. Aphids on plants growing in unfertilized (deficient) plots reproduced at an earlier age (approximately nine days) and produced more nymphs (nearly 90 per female) than aphids on plants growing in K-fertilized plots (first reproduced at 11 days, 60 nymphs total).
Hypothesis #4: K-deficient plants are nutritionally “better” for aphids Answer: Probably. Abby found that the proportion of the amino acid asparagine was greater in phloem sap from deficient plants. Aphids feed on phloem sap, a poor source of nutrition because it is low in nitrogen in the form of amino acids. Asparagine is a non-essential amino acid that is an important nitrogen source in the aphid diet; aphids can convert asparagine into essential amino acids lacking in their diet! How do aphids do this? They have friendly symbiotic bacteria living in their guts that do the job for them. So, K-deficient plants do appear to be nutritionally better (i.e. aphid candy), which may partially explain the quicker and greater reproduction on such plants. So what? First, this research demonstrates that crop fertility can effect the population of, and damage from, an insect pest. If you need a reason to spend time and money soil sampling and following recommendations for applying potash to build soil K levels, reducing the impact of soybean aphid is a good one. Second, even if you don’t plan to apply potash, this research still provides you with valuable information to select which fields to scout first and more often. Fields with a history of K deficiency, or a soil type susceptible to deficiency, or fields planted after alfalfa are all at greater risk for an aphid outbreak. In 2007, a very low aphid year in Michigan, the only fields that went over threshold in August were K-deficient fields in southern Michigan. The link between potassium deficient and soybean aphid is real, and can lead to yield loss! If you are a glutton for punishment, and want to read a journal article about this research, visit: http://www.ingentaconnect.com/content/esa/envent/2007/00000036/00000001/art00004 |
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| Weed control in soybeans can benefit from preemergence soil-applied herbicides The use of postemergence (POST) glyphosate in Roundup Ready soybeans has been the primary weed control program used by many Michigan soybean growers. While this system has seemed to simplify weed management, relying on total postemergence herbicide programs can be difficult to manage if not properly implemented. The flexibility in application timing that glyphosate offers may make it easier to control larger weeds, however the benefits of early-season weed control to protect crop yield can be lost if applications are not made in a timely manner. Additionally, untimely applications can lead to a reduction in weed control. Another thing to consider is by relying only on glyphosate as the weed control strategy. This system puts tremendous selection pressure on the weeds that could possibly lead to the development of herbicide-resistant weeds. One way to help overcome some of these concerns is to implement the use of a soil-applied or preemergence (PRE) herbicide into your soybean weed control program. Using a planned PRE residual herbicide followed by a POST glyphosate application can result in more consistent weed control, reduces the size and number of weeds present at the POST application timing, and offers greater flexibility in the POST application window. One of the concerns that many producers have in implementing a PRE herbicide is the economics. While a PRE herbicide may increase the cost of your weed control program, resulting benefits often make up for the cost by increasing weed control and yield. Below are some of the benefits realized by PRE followed by POST weed control programs. Reduced early-season weed competition Using a PRE herbicide will control a number of weeds that would have emerged and competed with the crop as it becomes established. While early-season competition may not be a factor if the POST application is timed appropriately, (remember that weeds can increase in size in a number of days and if you are trying to spray a large number of acres or you become delayed in your applications due to rain) early-season weed competition can become a problem. Remember, for timely POST applications to avoid yield losses due to early-season weed competition MSU recommends weeds should be controlled before they are 4-inches in height in 7.5- and 15-inch rows and 6-inches in height in 30-inch rows. Consistent control of weeds that continually emerge Several weed species have continual emergence or emerge only later in the season. These species can include: annual grasses, giant ragweed (southern Michigan), eastern black nightshade, pigweeds and common lambsquarters (occasionally). Because of the later emergence of these weeds they may actually emerge after the POST herbicide application and can produce seed and become a problem at harvest. PRE herbicides allow for a delay in the POST applications, which will result in more effective control of these late-emerging weeds. Consistent control of hard-to-control weeds In Michigan, we have seen a few weeds that have become harder to control with one POST glyphosate application. Common lambsquarters and giant ragweed are examples of weeds that are not always effectively controlled with glyphosate. A PRE herbicide can aid in control by providing effective control or suppression of these weeds, so they are easily controlled with the POST application. For example, over several MSU trials a PRE residual herbicide followed by POST glyphosate treatment has provided more consistent control of common lambsquarters than 1- or even 2-applications of glyphosate (Figure 1). Effective control of perennials Control of perennial weeds is more effective in the later stages of growth (bud to flower stage). Because PRE residual herbicides will provide initial control of annual weeds, the POST glyphosate application may correspond more appropriately to the stage of growth needed for perennial weed control. Weed resistance management One possible long-term benefit from including a PRE herbicide in your weed control program is the implementation of herbicide resistance management strategies. A PRE herbicide would include another mode of action into the weed management program and reduce the number of weeds present for the POST application. Ultimately, these two benefits will relieve the selection pressure of a glyphosate-only weed management system. This has become a much greater concern as we see more glyphosate-resistant weeds being reported around the United States.
( ) = Number of observations for each treatment. This data is a compilation of 6 years of research trials conducted at Michigan State University (C. Sprague, 2005). |
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| Delayed preemergence and early postemergence herbicide applications in corn 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. However, there can be 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: to use an herbicide program typically applied before emergence; or switch to a total postemergence strategy. There are several possible herbicide programs with each strategy. 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 H2O/Pendimax, crop safety will be greater if the rotary hoeing is done before herbicide application. Herbicides typically applied preemergence are listed in Table 1K (pg. 46) in the 2008 Weed Control Guide for Field Crops. Many of these herbicides are also labeled for application after corn emergence. Axiom and Princep7 should only be applied before corn emergence. To avoid confusion, tank mix combinations are not included in this table. Details on the specific restrictions for tank mixtures can be found on herbicide labels. Some herbicide labels allow application to emerged corn using 28 percent liquid nitrogen fertilizer as the herbicide carrier; however, we advise that all herbicide treatments to emerged corn be applied with water as the carrier. Applying herbicides to emerged corn with 28 percent 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. For several years, MSU has demonstrated the importance of timely herbicide applications to prevent the loss of yield in corn. We have shown that it is necessary to control weeds before they reach four inches of growth to prevent measurable yield reduction. Two-pass herbicide applications (preemergence followed by postemergence or two postemergence) or timely single postemergence applications with residual control are most effective at preserving yield and maximizing gross margin. Information about the effectiveness and economics of preemergence and post emergence herbicide programs can be found in the summary of Commercial Herbicide Program Comparisons found on the MSU Weed Science website at http://www.msuweeds.com/publications/. Herbicide options for total postemergence weed control are 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. |
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| Allocating fertilizer resources for crop production The price for potash will be considerably higher this year than last year and supplies will be tight. Potash may be allocated based on past use. This is the result of an increasing worldwide demand for potash. Faced with this situation, farmers need to evaluate how they can best use the funds they have allocated for fertilizer inputs. Soil test results are an excellent guide for deciding how much lime, nitrogen, phosphorus and potassium to apply on each crop in each field. Collect soil samples and test as soon as conditions permit or work from recent soil test information, within the last 2 to 3 years. Look first at the soil pH. If it is below 6.0, the best first investment is for lime. In many situations, the return on invest is best with lime, both short and long term. When the soil pH is below 6.0, applied fertilizer nutrients or indigenous soil nutrients are not used as efficiently by crops. Nearly 70 percent of soils in Michigan used for field crop production contain more than adequate available phosphorus (soil test over 25 ppm) to produce top crop yields. For early planted corn, applying 25 lb P2O5 per acre as a starter is more than adequate. When the soil test is less than 25 ppm, then more may be needed for some crops. In general, spending limited resources on phosphorus will not provide the most potential for a good return on investment. In contrast to phosphorus, less than 25 percent of the soils in Michigan used for field crop production contain adequate potassium. The probability for a good return on investment is generally better for potassium than for phosphorus. If the higher potassium price or a limited supply prevents the purchase of enough potash to meet the need for all fields, what is the best strategy to allocate the potash that can be purchased? The crop yield response to incremental additions of potassium or other nutrients can be characterized as the “curve of diminishing returns.” This means that the increase in yield from the first increment of potassium added (say 50 lb K2O per acre) is greater than the second. And return from the second increment is greater than from the third, and so forth. Eventually the cost of an additional increment of potassium is greater than the value of the yield increase. This being the case, it is better to apply or allocate potash first to fields with lower soil potassium values, where there will be a good yield response, than to those fields that have close to adequate levels. A soil test report will indicate these differences. The potassium recommendation for higher testing soils will be less than for low testing soils. One approach to deal with a reduced allocation is to only broadcast potash on fields where the recommendation is for more than 50 lb K20 per acre. For fields requiring less than 50 lb K20 per acre, use 20 - 25 lb K20 per acre in the starter fertilizer. This can be especially beneficial when planting corn no-till or into high residue fields. Another approach is to reduce the amount of K2O recommended and applied to each field by a set amount, for example 25 lb K2O per acre. In this way, the impact on field yields from having to apply less potash on a whole farm basis will be minimized and return on investment in potash will be optimized for the resources available. |
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| Managing higher priced fertilizer inputs Increasing worldwide demand for nitrogen, phosphorus and potassium has brought about significant increases in the costs of these materials for the 2008 growing season, especially potash. The supply of potassium may also be limited. Faced with this situation, farmers may have to make decisions on how to get the best return from the fertilizer they are able to purchase. Following are some suggestions. 1. Soil test. A soil test indicates the available nutrient status of the soil, the need for lime and how much nitrogen, phosphorus and potassium are needed for the crop to be grown. Test results from samples collected within the last two to three years can be used as a guide. For fields where no soil test information is available, collect soil samples as soon as possible and have them tested. 2. Apply lime where needed. Maintaining the soil pH between 6.0 and 6.8 improves nutrient availability and crop growth. In many situations, the return on invest is best with lime, both short and long term. When the soil pH is below 6.0, applied fertilizer nutrients or indigenous soil nutrients are not used as efficiently by crops. 3. Take credit for nutrients contained in manures, composts or other materials applied to crop fields. Nutrients contained in these materials are readily available and can offset the need for purchasing any additional fertilizer. Have manures and compost analyzed for the nutrient content. 4. Apply phosphorus only where needed. As the result of past buildup, 70 to 75 percent of Michigan farm fields contain adequate or above levels of phosphorus. Now is the time to use some of that phosphorus banked in the soil. 5. Focus of potassium. Only 20 to 25 percent of Michigan farm fields contain adequate levels of potassium. Increase the amount of potassium included in starter. At a 2 inch by 2 inch placement up to 100 pounds per of K2O per acre can be applied without concern for injury. Placement of potassium is especially important for corn planted no-till or into a lot of residue. By including some potassium in the band fertilizer, the total amount applied per acre may be reduced because of the increased effectiveness. 6. Band-apply nutrients. Band applied nutrients are used more effectively than broadcast nutrients. In high P testing soils, early growth from banded fertilizer comes more from nitrogen and potassium than phosphorus. Overall, reducing phosphorus in favor of nitrogen and potassium may prove beneficial. 7. Apply P and K first to fields most in need. The crop yield response to incremental additions of potassium or other nutrients can be characterized as the “curve of diminishing returns.” This means that the increase in yield from the first increment of potassium added (say 50 lb K2O per acre) is greater than the second. And return from the second increment is greater than from the third, and so forth. Eventually the cost of an additional increment of potassium is greater than the value of the yield increase. This being the case, it is better to apply or allocate potash first to fields with lower soil potassium values, where there will be a good yield response, than to those fields that have close to adequate levels. 8. Reduce amount of K applied uniformly across all fields. In fields that need K, applying slightly less, e.g. 25 pounds per acre, than is needed will have only a minimal, if any, effect on net income. Work from soil test results. 9. Apply preplant nitrogen close to planting time. This will minimize the length of time nitrogen is at risk of lost by leaching or denitrification before crop demand increases. 10. Use a presidedress soil nitrogen test for corn to determine need for more nitrogen. Some soils can provide significant amounts of available nitrogen, especially where cover crops or animal manures or a previous legume crop is incorporated prior to planting. |
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| Fusarium head blight risk assessment models and DON prediction model What tools are available to estimate the risk of Fusarium head blight (scab) and levels of DON (vomitoxin) and help growers determine whether fungicide applications are advisable to protect wheat against head scab? Two models have been developed to serve as decision aids for growers to determine whether an application of fungicide should be made to control Fusarium head blight (FHB). The Penn State Model and the Ontario DONcast model are described in this article. Through research funded by Project GREEEN in 2006-2007, both the Penn State and DONcast models were validated in Michigan using weather information and collecting field data from grower locations and research plots. Although epidemic conditions for FHB did not occur during either year of the study, the predictions made by each model showed reasonable agreement with field sample observations collected from grower locations and research plots during both years of the project. Although predictions for other categories of susceptibility seemed to be fairly accurate, there was a tendency to overpredict DON levels in wheat varieties that were classified as highly susceptible (HS) using the DONcast model. Field evaluations for both models will continue in Michigan in 2008. How does the Penn State model work? Scientists have developed scab risk assessment models through projects with the U.S. Wheat and Barley Scab Initiative. The Penn State models were developed using data from wheat head blight epidemics around the country, and represent seven years of development and testing. Although models have been developed for both winter and spring wheat, the winter wheat model will be most useful for the majority of Michigan growers, as only a very small percentage of acres in Michigan are spring wheat. Data for the Penn State models (in Michigan) are generated from MAWN and National Weather Service locations. The addition of the Enviro-weather stations in 2007 increased the number of weather locations in the Lower Peninsula for the model from 45 to 89. The Penn State winter wheat model uses only data from the week before flowering to estimate the risk of a scab epidemic with 10 percent or greater field severity. Risk is calculated based on the number of hours when both relative humidity is greater than 90 percent and temperatures are between 48°F and 86°F during the week before flowering. Humidity and temperatures in this range are favorable for the reproduction of the fungus (Fusarium graminearum) that causes head scab. The spores must germinate and infect the flowers in order for the pathogen to cause disease. Moisture, in the form of high humidity, rainfall, dew or ground fog has the greatest influence on infection. Generally, warm temperatures (75-86°F) and extended periods of wetness (overnight and morning) tend to be most favorable for infection. Cool temperatures tend to limit fungal growth, but long periods of wetness can compensate for cooler temperatures. The Penn State models are at: http://www.wheatscab.psu.edu The models can correctly identify years with severe head blight 7 out of 10 years. The color codes on the map indicate the relative risk of an epidemic. Red = High risk; Yellow = Moderate risk; Green = Low risk. The circles and triangles on the map represent weather stations that can be selected to provide site-specific estimates of disease risk. The models and evaluation of disease risk should begin about 1 to 2 weeks prior to anthesis (flowering). Many users have found that the models will produce patterns of persistent moderate disease risk, or steadily increasing disease risk during this time period. The final decision to apply a fungicide should be made as close to flowering as possible. You should monitor local weather conditions during the week before flowering to help you decide whether infection is likely to occur in your area. Michigan specific comments will be posted to the website again this year. How does the DONcast model work? The DONcast model, developed at the University of Guelph, (Ridgetown, ONT, CA) makes a prediction at heading for the expected level of deoxynivalenol (DON, vomitoxin) at harvest. There are a number of components that make up the DONcast model. Environmental effects such as temperature, relative humidity and rainfall account for 48 percent of the model. The level of susceptibility of the wheat variety-moderately resistant (MR), moderately susceptible (MS), susceptible (S) or highly susceptible, (HS) account for 27 percent of the model. Whether the previous crop was a host for the FHB fungus such as corn, wheat, barley or something else represents 14 percent of the model, and tillage accounts for less than 5 percent. Using these inputs, DON predictions are made for a specific heading date, corresponding to when 75 percent of the wheat heads have emerged. This model allows for a 2-3 day window after heading to make fungicide applications if needed, depending on predicted DON values. The threshold for recommending a fungicide application for this model is if predicted DON levels equal or exceed 1 ppm. Although there is currently no Michigan based DONcast, growers who are interested in the Ontario DONcast model can access it at the Weather Innovations website, http://www.weatherinnovations.com/DONcast.cfm When is wheat most vulnerable to FHB infection? Before the head emerges from the boot, it is protected from Fusarium. The head is most vulnerable to infection from the time that flowering begins to the early milk stage. After mid-milk, it becomes more difficult for the fungus to infect the kernel and damage is less severe. The most severe head blight epidemics have involved multiple infection periods and cultivars susceptible to spread of the fungus throughout the head. Depending on the fungicide used, the window for management of head blight extends from heading to 50 percent flowering, with the optimum period of fungicide application being at Feekes 10.5.1 (about 15-25 percent of heads flowering). How do I decide whether I should apply fungicides for FHB to my wheat? Fusarium head blight has the potential to cause significant losses in both quality and yield. Discounts tend to start at lower ppm DON levels in white wheats than in red wheats. When and if a fungicide should be applied for FHB depends on the level of risk the grower is willing to accept. Although considerable effort is ongoing to develop FHB resistant varieties of wheat, the use of fungicides to control FHB and reduce levels of deoxynivalenol (DON) is still a primary management strategy. Timing of the fungicide application is especially challenging. Growers have an application window of only a few days for effective control of FHB and DON. Unlike some of the common foliar diseases of wheat, by the time scab symptoms are visible, the window for fungicide treatment is already closed. Models are meant to serve as decision aids to help growers decide whether or not an application of fungicide to control FHB is warranted. The April 17, 2008 Field CAT Alert contained a partial budget analysis to help you determine whether an application of fungicide was likely to be economical. A table of fungicides currently registered in Michigan for FHB and their efficacy ratings can be found at the Field Crops AoE website. If additional fungicides become registered for FHB in Michigan, we will announce them in the Field CAT Alert. |
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| Regional reports 1 – Southeast Weather This weather has allowed fields to dry out and planting to begin. However, scattered rain and even light hail occurred on Monday, April 28. The Enviro-weather station in Dundee recorded 25ºF yesterday morning. April had warm and cold weather, with both rain and snow and was generally wetter and cooler than normal. Although soil temperatures have dipped below 50ºF, now that May is here, farmers will keep planting. Crop report Alfalfa is growing nicely with most stands about 8 to 10 inches tall. I have not seen any alfalfa weevil feeding of any significance. Stands are generally thinner due to the harsh winter weather. We will have less alfalfa harvested this year as some fields went into wheat last fall or will be planted to corn this spring. I anticipate that several new fields will be planted this fall. Corn planting started last week and is at full speed ahead now that fields are drying out. No corn is emerged and soil temperatures are no longer a factor as the forecast is favorable. Lots of triple stack corn was sold this past winter. One farmer was audited this past year for compliance with the Bt refuge. Oats were “mudded” in a couple of weeks ago. Soybean planting has also started, though none have emerged. Lots of treated seed sold this winter. We will likely be getting the soybean aphid suction trap up and running by next week, once the new supplies arrive. Wheat is at Feekes’ growth stage 5. Most fields have had nitrogen applied and are nice and green, with very good stands. Miscellaneous Although planting is behind the pace of the past several years, there are several new tractors and planters out there and none are smaller than the ones they replaced. This will be an interesting year with all the winter talk of using fungicides and insecticides post applied to corn and soybeans to increase yields. |
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| 2 – Southwest
Weather Unexpectedly dry conditions over the past two weeks have allowed many producers to catch up with tillage work. This should be considered a major plus because there was a lot of moisture in the forecast during this period. Rainfall accumulations with the last cold front were widely variable throughout the region. While the majority of the area received at least some precipitation, some areas received very little. The rainfall totals are running about 1.5 inches behind normal over the last two weeks in many southwestern Michigan locations. Extremely cold air temperatures, as low as 22ºF, were recorded overnight on April 30. Crop report The earliest planted commercial corn fields could easily be rowed by early last week. While very few acres had actually emerged by early Wednesday morning, the temperatures were cold enough that chilling injury in addition to the direct frozen emerged tissue could potentially be an issue. Excellent soil moisture conditions have allowed for a great deal of corn to be planted in the last couple of days. We are able to find several fields in St. Joseph County that have at least some populations of Asiatic garden beetle white grub larvae. If you see lots of white grubs in St. Joseph or surrounding counties, you may want to consider using a soil insecticide, especially on sandy soils, to protect your corn plants. The same is true for seed corn fields. Seed corn planting will not begin until after this weekend. Many fields that will be planted early are fit and ready to go. We look for a record number of acres of seed corn to be planted in southwestern Michigan this season. Soybean planting has also really picked up the pace. Most seed corn producers in St. Joseph County are trying to get beans in early to be ready to plant seed corn starting next week. We did have a couple of fields that had emerged, and were very likely damaged by the frost. With temperatures in the lower 20’s, it takes almost no length of exposure to damage the growing points on soybean plants. Growth was kicked into high gear for alfalfa and pastures following the week of warm weather since the last report. We are unsure how the freeze will effect subsequent alfalfa growth in the area. Alfalfa weevil larvae feeding was reported in the Paw Paw area in Van Buren County. Wheat is mostly in the Feeke’s 5 growth stage at this point. Most fields have greened up nicely following N applications and were growing well. Not a lot of problems with winter annual weeds or leaf diseases at this point. |
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| 3 – West Central
Weather It has been quite dry for the past two weeks with light showers in the Montcalm area on the April 25. High temperatures have gone from quite warm last week with highs in the 70s to quite cool this week with highs in the lower 50s. Low air temperatures have been in the 30s and 40s with two notable exceptions of lows in the 20s. A low temperature of 21.9ºF was recorded on April 30 at the Montcalm Experiment Farm Crop report Alfalfa growth progressed rapidly last week with many stands at 8 to 10 inches in height. Frost damage has been observed after the last two to three nights of very cool temperatures. The extent of the damage should be apparent in the next couple of days. Grasses are 10 to 12 inches and growing rapidly. Approximately 5 percent of the corn crop is planted. Much tillage has been done. If the weather holds next week, we will see major progress. Very limited planting of soybeans has occurred. Wheat is in growth stage Feeke's 5-6. A significant portion of the crop has yet to be topdressed. Most fields look good. Oat planting is nearly complete with much of the crop emerged. |
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| 4 – Central
Weather There has been very little rain over the region in the past two weeks. Field conditions vary a great deal with some fields still very wet. Soil temperatures have cooled this past week with several cold mornings. Temperatures have gotten down into the mid-twenties. Most farmers are able to start planting in pretty good field conditions. A good rain would be helpful as long as it comes easy. Crop report Corn planting is well under way. Most farmers have been planting since late last week and this week. Most report good progress and planting conditions average. There are a few acres of soybeans that have been planted. Growers are cautioned that with the low germination of some of this year’s soybean seed it may be a good idea to hold off and plant soybeans when the soil temperatures have warmed up. Planting into good conditions can help insure good stands. Wheat is in Feeke’s 4-5 and generally looking good. Most nitrogen has been applied at this point. There are still herbicide applications that will need to be made. Know what growth stage your wheat is in as we are getting past the growth stage when growth regulator herbicides can be used safely. The alfalfa crop is growing nicely with most of the fields between 6 to 8 inches. There is no reported alfalfa weevil feeding at this time. Some feel harvest will come early this year. Oats planting is nearly complete. The early planted fields have emerged. Sugar beets are planted with some beginning to emerge. |
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| 5 – Thumb
Weather The weather has been dry and cool. Most of the area received a light rain a week ago Thursday, April 24. We are in need of warmer air temperatures and a nice rain. The lack of moisture has allowed planting to progress rapidly. We received a heavy frost last Wednesday morning, as did the rest of the state. Crop report Alfalfa’s new growth looks good. Most fields that have been walked are 8-14 inches, with better growth on lighter ground. Winter damage was light, and no insect damage has been reported. Sugarbeet planting is pretty much done, and some fields have emerged. Other fields need a rain to emerge. A little frost/freeze damage was found in some low areas. Corn planting is progressing nicely. Most farmers have at least half of their crop planted and several are completed or nearing completion. Wheat is at Feekes 3, 4 and 5. Jointing may begin next week for the most mature fields. Ice sheeting damage is extensive. We have probably lost over 5 percent of our yield potential. Perhaps 1.5 percent of our acreage has been abandoned. Very low disease pressure to date. Using a foliar fungicide treatment at this time would not be recommended. Some soybeans have been planted. We would expect soybean plantings to ramp up during the next several days, weather permitting, especially as corn planting wraps up. |
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| Weather news An area of low pressure over the central Great Plains Thursday, May 1 is expected to strengthen and move towards Michigan this weekend, bringing an extended period of unsettled weather to the region. A warm front extending eastward from an area of low pressure will approach the state Thursday, bringing the chance for showers to western and southern sections of the state by late in the day. The low pressure will move slowly northeastward through the region by late Saturday or Sunday, bringing an extended chance for showers and thunderstorms each day through Sunday. Best chances for rainfall statewide will be late Thursday, Friday and early Saturday. Some severe thunderstorms are possible across southern and central sections of the state Friday into early Saturday, especially if there are more breaks in the cloud cover Friday than expected (i.e. more sunshine). Precipitation totals through Sunday will top 1-inch in most areas of the state, with some 2 inch totals possible across central sections of the Lower Peninsula. Fair and drier weather is expected again by late Sunday continuing into the middle of next week. High temperatures will range from the mid-50's north to upper 60's south Thursday to a range from 56ºF north to the low 70's south Friday. Low temperatures will range from the upper 30's north to mid-50's south Friday morning to the mid-30's north to mid-40's south by Sunday. Further ahead, medium‑range forecast guidance suggests a series of upper air troughs moving from the western United States eastward into the Midwest, with an active storm track across the Great Lakes region. Both 6-10 day and 8-14 day outlooks covering May 6-10 and 8-14 call for above normal precipitation totals statewide. Temperatures are forecast to range from near normal levels across southeastern sections of the state to below normal levels in the northwest during the 6-10 day time frame, and remain at below normal levels during the 8-14 day period. Due to some disagreement among the models used in the development of the outlooks, forecaster confidence is considered lower than normal. |
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