May 29, 2008
In this issue
§ Fungicide tank-mixtures with sugar beet herbicides: What are the risks?
§ Maximize glyphosate activity with a few simple tips
§ Herbicide sensitivity in potatoes
§ Cold weather stress on corn and soybean
§
§ Considerations for raising irrigated wheat
§ Agricultural labor statistics for spring 2008
§ Regional reports
§ Weather
Christy Sprague
Crop and Soil Sciences
As we are on the front edge of the fungicide applications for Rhizoctonia management in sugar beets, many of these applications often coincide with herbicide applications for weed control. While tank-mixing these two pest management practices could save extra trips across the field, there are some risks associated with tank-mixing certain herbicide programs with fungicides.
Quadris is the most commonly used fungicide for Rhizoctonia
management in
What about tank-mixing fungicides with standard split herbicide programs? Most of our research has shown that Quadris can be tank-mixed with a Betamix standard split program without severe sugar beet injury. However, in our plots and in growers’ fields there have been reports of sugar beet injury (leaf burn) from tank-mix applications of Quadris and a Progress standard split herbicide program. Again the best way to avoid this injury is to apply the fungicide and herbicide programs separately.
While we have more extensive data on fungicide tank-mixtures with conventional herbicide programs in sugar beets, last year we conducted a study where we wanted to determine if there would be any injury or sugar beet yield loss from tank-mixtures of glyphosate (Roundup OriginalMax) with different fungicides. We applied glyphosate alone and tank-mixed with Quadris, Gem, and Headline when sugar beets were at the 2- and 6-leaf stages. Very little injury was observed from these mixtures. However, if we added Dual Magnum or Outlook to the glyphosate plus Quadris tank-mixture injury was 31 percent and 13 percent respectively, seven days after application. The injury was mostly leaf necrosis (burning) and the beets quickly recovered. We also looked at combinations of glyphosate with fungicides typically used for Cercospora leaf spot management. At the time of a typical fungicide application for Cercospora (55 DSVs), we applied glyphosate with Copper Sulfate (Champ II), Penncozeb, Eminent, Gem, Headline, SuperTin and Topsin M plus Penncozeb. We did not observe any sugar beet injury from these treatments. Yield was not reduced in any of the treatments as compared with glyphosate alone treatment. So from one year’s research, we found that glyphosate could be tank-mixed with fungicides. However, Dual Magnum or Outlook should not be added to these combinations or injury may occur. Even though glyphosate can be tank-mixed with a fungicide without causing sugar beet injury, differences in nozzle types and application timings may affect both disease and weed control. Caution should be taken in matching up the correct application methods and timings.
Christy Sprague
Crop and Soil Sciences
Postemergence herbicide applications for weed control in soybean are quickly approaching. There are several things that should be considered to maximize weed control with glyphosate from these applications in Roundup Ready soybean. Following these guidelines can help reduce the risk of glyphosate failures, as well as reduce the chances of lower soybean yields due to weed competition.
There are over 30 different glyphosate products that growers
in
Another difference in glyphosate products is whether a surfactant needs to be added to the spray solution or if the formulated glyphosate product has a built-in adjuvant package. Products like Roundup WeatherMax, Touchdown Total, and several others have built-in adjuvant systems. Even though all of these products have a built-in adjuvant system there can and many times are differences in the type of surfactant formulated in the product. These differences may equate to differences in weed control under extreme conditions. However, under most conditions there are no differences between these products especially when they are used at the correct rates, at the appropriate application timings. For products where the addition of a surfactant is recommended add a high quality non-ionic surfactant at 0.25 to 1.0 percent v/v. Table 10 also includes information on whether the addition of a surfactant is recommended for a particular glyphosate product.
Ammonium sulfate (AMS) should always be added to all glyphosate products. We recommend adding dry spray grade AMS at 17 lbs/100 gal or the equivalent of 17 lbs/100 gal of liquid AMS products. The addition of AMS minimizes the negative effect of hard water on glyphosate activity and is important for velvetleaf control, regardless of water quality.
Applying the appropriate glyphosate rate in glyphosate-resistant soybean is important for consistent weed control. Proper glyphosate rates should be based on weed type, weed size and spray volume. In most cases the appropriate rate to use for weed control in glyphosate-resistant soybean is 0.75 lbs a.e./A of glyphosate. This rate will effectively control several annual weed species between two and eight inches tall. However, if weeds become larger or if harder to control species such as common lambsquarters or giant ragweed are present, increase the glyphosate rate to 1.1 lbs a.e./A or 1.5 lbs a.e./A to adequately control these weed species. In addition, by matching the appropriate glyphosate rate to the correct weed size you reduce your chances of weed control failures under extreme conditions.
Glyphosate application timing is everything. It is important to make timely glyphosate applications to minimize the chances of soybean yield loss due to early-season weed competition and to maximize weed control. The optimum time for glyphosate applications is when weeds are four inches tall in narrow-row (7.5 and 15 inches) soybean and six inches tall in wide-row (30 inches) soybean. Controlling weeds at these times reduces the chances for soybean yield loss, as well as reduces the risk of weed control failures of larger weed that may be under stressful conditions (drought, stem-boring insects, coverage issue, etc.).
Windy conditions in the narrow application windows that we see this time of year make the use of drift reducing nozzles or drift reducing agents almost a necessity to reduce or prevent off-site particle drift. When using these technologies, it is important to know their limitations. Using these technologies without the proper spray pressure and spray volumes can lead to reduced weed control with glyphosate. To maintain effectiveness with these technologies make sure to follow manufacturer’s recommendations on pressure and volume, apply the appropriate glyphosate rate for the target species, and always check for a uniform spray pattern. Combinations of some of these technologies can reduce spray coverage that may result in reduced weed control. Following these guidelines, particularly checking the spray pattern, can help determine if the weeds are receiving an adequate dose of the herbicide for weed control.
Following these guidelines will help maximize glyphosate performance and reduce the risk of soybean yield loss due to weeds in the 2008 season.
Herbicide sensitivity in potatoes
Wesley Everman
Crop and Soil Sciences
Potatoes have a wide variation in
growth habit and response to environment, particularly due to genetic variation
which can be attributed to its polyploidy nature. It is therefore no surprise
to those who grow potatoes that varieties respond differently to herbicide
applications. Herbicide options for weed control in potatoes are limited to
several compounds that have been around for decades with a few newer ones mixed
in. Herbicide injury in potato varieties with Sencor is well documented and is
taken into consideration when planning Sencor use for weed control. The cool
weather this spring has created conditions that favor the enhancement of
herbicide injury in crops. Cool weather slows the metabolism of herbicides in
the crop, which allows the herbicides to block pathways and induce injury not
normally observed in potatoes. Coupled with the inherent sensitivity of some
varieties, severe injury can occur.
Potato varieties, such as Atlantic or the newer Silverton Russet, grown in Michigan that show varietal sensitivity to herbicides on a normal year, may show greater injury when the weather has slowed potato growth. Potatoes are commonly sensitive to Sencor/Lexone (metribuzin), however, herbicides that potatoes are not generally sensitive to, including Dual Magnum /Cinch/Parallel/Stalwart (metolachlor), Outlook (dimethenamid-p), Lorox (linuron) and Matrix (rimsulfuron) can cause injury under adverse conditions, such as cool, wet weather, when soil applied. Injury can also be observed after herbicide application in hot, humid weather. It is important to time herbicide applications to avoid coinciding with stress-inducing conditions to help avoid injury. Some herbicides such as EPTC can cause wrinkled leaves and other injury if applied at a rate exceeding label recommendations. Drift is also a concern during the growing season with glyphosate and phenoxy herbicides, such as 2 4-D, causing injury to emerged plants.
This spring injury due to the cool weather has been observed after Sencor and Lorox applications. Injury symptoms for Sencor (Photo 1) include interveinal whitening and yellowing of the leaf, generally most evident on the older leaves. Similar injury symptoms occur with Lorox (Photo 2), however whitening and chlorosis often occurs on the leaf margin. Many nutrient deficiencies and environmental stress responses can resemble herbicide injury, therefore if you suspect you have herbicide injury, contact your local Extension educator to help diagnose symptoms accurately.
Herbicide rates and recommendations for weed control in potatoes can be found on pages 118 to 123 with weed and crop response ratings on page 125 in 2008 Weed Control Guide for Field Crops.
Kurt Thelen
Crop and Soil Sciences
It appears that most of
Check low-lying areas of fields where natural “air drainage”
is restricted for frost damage first. To assess seedling viability, split a
plant lengthwise through the stem. The growing point should be relatively firm
and white or cream colored. Darkening or softening of the growing point
indicates a nonviable (dead) plant. Replanting of frosted areas in soybean may
be warranted if these areas are extensive, however, as indicated above, it
appears that most of
Darryl Warncke
Crop and Soil Sciences
Nitrate testing of soil is an excellent and inexpensive way
of evaluating the available nitrogen (N) status of your soil. Nitrogen available
in the soil is nitrogen that does not need to be purchased.
The soil nitrate test measures only nitrate N. It does not measure ammonium N or organic N. If samples are taken in late May or early June when corn is near V3 or 4, much of the ammonium and some of the organic N will have been converted to nitrate and will show up in the test.
Soil samples may be taken any time, however, samples taken in early June after the soil has warmed up usually contain the greatest amount of nitrate N. The June test measures both residual nitrate N from the previous year and recently mineralized N from organic matter.
Soil samples taken in early spring, April or early May, measure primarily residual nitrate and a limited amount of the mineralized organic N. Therefore the amount of N credit will be smaller. However, testing in early spring may still be well worth the effort.
Samples taken just prior to sidedress time can be used to the greatest advantage to determine the appropriate rate of sidedress N. The soil nitrate test is most reliable in fields receiving less than 50 lbs N per acre prior to planting. When sampling fields where 28 percent N solution (UAN) or anhydrous ammonia has been knifed in pre-plant, you will need to double the number of sub-sample cores to avoid problems associated with sampling N fertilizer bands.
Samples taken in June from fields where N has been broadcast prior to planting can be used as a guide to adding additional N through the irrigation system or for planning next year’s application. If the soil test in June indicates more than 25 ppm, no additional N is needed. Soil test levels in excess of 40 ppm at this time indicate excess soil N.
Samples taken in the fall may be used to evaluate how much N is left at the end of the season. Soil test levels in excess of 15 ppm at harvest indicate excess soil N.
Growers who have excess soil N in June or at harvest time, should consider reducing next year’s fertilizer rate or use the presidedress test to determine the appropriate N rate.
Sample all fields where corn is to be planted. Fields receiving manure and following legumes, which are sampled in June, will likely contain the most nitrate. Sampling these fields earlier will result in less than the maximum N credit that should be taken because easily decomposed organic N will not be measured by the test. See Extension Bulletin E-2344 and E-2567 for determining the appropriate N credit from manure and legumes if samples are taken in early spring.
Fields that show the most nitrate N are those with fine textured
soils (i.e. loam, clay loam and clay) that were heavily fertilized with N the
previous year.
Soil sample boxes and information on taking soil samples for
the nitrate test are available from your
Each sample should be a composite of 15‑20 soil cores taken from a uniform field no larger than 20 acres. Use a soil sampling tube. Take each core to a depth of 12 inches. Place the 15-20 cores in a clean pail and mix thoroughly. Save one quart of the sample for drying.
Air dry the soil sample immediately in a warm room. Spread out the sample and place it in front of a fan. Placing the sample near a hot air vent or space heater will speed up the drying process. Do not hold wet samples in a plastic bag for any length of time. Microbial action in wet samples can significantly change the nitrate test results.
Soil nitrate tests are done in the MSU Soil and Plant
Nutrient Lab. See your county
Extension office for assistance in delivering your samples to the MSU lab. Dry
soil samples may be mailed directly to the MSU Soil and Plant Nutrient Laboratory,
Currently N recommendations for corn use the Maximum (economic) Return To N (MRTN) rate based on several years of field research. Nitrogen recommendations vary with the productivity of the soil and the N:Corn price ratio. The accompanying table gives the current MSU N recommendations for corn. The amount of N credit given is obtained by multiplying the concentration (ppm) of nitrate in the surface soil sample by a factor of 6. EXAMPLE: If the test shows 10 ppm of nitrate in the soil sample, the estimated N credit is 60 lb/A.
Soil N:Corn Price Ratio
Productivity1 0.10
0.15 0.20
Suggested N Rate – lbs N/acre
2Range
1Low/Med 115-145 105-135 95-125
High/V. High 135-165 120-150 105-135
1Low: Ave Yield < 120 bu/a; Med: = 121to 150 bu/a;
High: = 151 to 180 bus/a; V.High: = over 181 bu/a.
2Range
approximates ± $1.00 of the MRTN rate. Using
the higher value is suggested in 2008.
The cost of soil nitrate analysis by
Send your samples to:
MSU Soil and Plant
Nutrient Lab
A18 Plant & Soil Sciences Bldg., MSU
517-355-0218
Website: http://www.css.msu.edu/SoilTesting.cfm
Bruce MacKellar; Extension educator, Field/Specialty crops
Lyndon Kelley, Extension educator, Irrigation
Raising wheat or other small grains on irrigated land has
not been a common practice in southwest
Irrigation scheduling is the term given to deciding how much and when to apply irrigation water. The over-arching principle in irrigation scheduling is to replace the water used by the plant for evaporation and transpiration. (Evapotransporation or E.T). The evapotransporation rate for crops are established by raising plants in a container of know volume on scales (called weighing lysimeters) that record reduction in the weight of the soil in the root zone as the crop uses water and as rainfall or irrigation increases the soil root zone weight. The maximum water use by wheat and most small grains is 0.19 inches of water per day at flowering for a 75ºF average temperature day. This means that a one inch irrigation or rainfall event would last a little more than five days during this critical period. The accompanying chart shows how wheat E.T. increase, peaks and declines as the crop matures and how crop water use increases as average daily temperatures increase.
The complete table and discussion can be found at the
While there may be lower incidence of leaf diseases and
fusarium head blight (scab) in irrigated wheat in dry years, unanticipated
rainfall following irrigation can lead to more disease challenges. Most of the
fungal pathogens that impact wheat thrive when extended periods of leaf wetness
or soil saturation occur. The most critical time for fusarium head blight
infection is during flowering (Feeke’s Growth Stage 10.5.1),
which unfortunately occurs during the period of the highest crop water usage. Fields
planted to commercial or seed corn the previous year may be more at risk of fusarium
head blight development because infected corn residue may serve as the inoculum
for the disease. The
There are several paper and computer systems available to
help irrigators schedule irrigation applications. These tools are “checkbook
type systems” that view the water in the soil root zone as your checking
account. Rainfall or irrigation serve as deposits in your account and water
used by the crop is considered a withdrawal. Overviews of irrigation scheduling
tools that are available in the
Vera Bitsch; Agriculture, Food and Resource Economics
This April, the hourly wage for agricultural workers in the
In addition to analyzing wage rates by type of worker, NASS
provides wage data by type of farm with slightly different results. These data
combine field workers and livestock workers, but exclude other typically higher
paid groups. The average hourly wage rates in 48 states, excluding
The hourly wage rates in the
To read Dr. Bitsch’s complete newsletter go to her website at http://www.msu.edu/user/bitsch. Under “News” click on “U.S. Agricultural Labor Statistics for Spring 2008” or click on “Agricultural Labor Issues in Michigan” for a list of available newsletters.
For more details, the NASS release is available at http://www.usda.gov/nass/. Select “Publications” and then “Reports Calendar” or “Publications” and then “Search,” by “Title” or “Subject” (Farm Labor).
Ned Birkey
Weather
Weather has continued to be cooler and drier than normal. Except for two days on Monday, (May 26) and Tuesday (May 27), the soil temperatures have continued to stay in the 50°F range.
Alfalfa first cutting has started. Yields may be down a bit, but the quality will be much improved. I have even seen a wheat field being baled into big, round bales.
Corn sidedressing
has started. Cutworms have been reported in a no-till field. Weed growth remains
as slow as the crop growth. Most fields are green to yellow, but no purple corn
was noted. Most fields are at the V3 stage. The first herbicide drift complaint
is underway, part of the problem may be the sprayer boom was higher than
recommended. The first corn nitrogen sidedressing rate study went in yesterday
for
Soybeans are emerging slowly with most fields at the VC to V1 stage. Three soybean planting rate studies have gone in, one in Monroe one in Washtenaw and the third in Lenawee County..
Wheat is heading
out with most fields in the Feekes’ 10.1 to 10.5 stage. The relatively cool and
dry weather has meant there is little disease pressure. A field day is planned
for the MSU Wheat Variety Trial in
Miscellaneous
Soil Nitrate testing and samples going to MSU will start next Wednesday, June 4, and then June 11. Farmers concerned about applying an agronomic rate of nitrogen, and who are planning to side dress should consider this soil test.
Bruce MacKellar
Weather
Temperatures have begun to
moderate following an extreme cold snap after the Memorial Day weekend (May
24-26). Soil moisture conditions were nearly perfect for the final major push
of soybean planting over the long weekend. The anticipated rainfall associated
with an approaching cold front on Sunday left the area with only light to
moderate precipitation totals, ranging from trace amounts to about 0.4 of an
inch in many places.
Commercial corn
planting is pretty much wrapped up in southwest
Seed corn planting continues to progress rapidly with the dry soil conditions. We may be around 70 to 80 percent completed with at least on inbred in the field on many of those not yet finished. Fields that were planted early continue to look good.
Soybean planting progress is moving towards completion with great planting conditions last weekend. Probably 50 to 60 percent of the crop has emerged with most stands looking good, especially on the lighter soils. We have seen some emergence issues for soybeans planted during the extended cold period. Cutworm activity has been light at this point, but can been seen on soybeans, perhaps more than on corn. Some fields have been treated for cutworms. Cass County CED Dan Rajzer reported that some soybean seedlings seem to have exhibited a horizontal growth pattern instead of emerging.
Winter wheat
continues to look good. Early planted
wheat along the
First cutting alfalfa harvest is underway. Yield levels appear lower this year than normal. Many fields have been treated for alfalfa weevil this year.
Fred Springborn and Roger Peacock
Another dry week has allowed field work to continue over the
region. Soils and crops are getting quite dry and irrigation rigs have been
running in many locations. The big weather news for the week has been the
widespread frost covering most of the region on the morning of Wednesday, May
28. Damage from this frost, appears to be limited with some areas receiving
more damage than others. High temperatures have been in the mid-60s to mid-70s.
Low air temperatures have been in the 30s and 40s with a low of 31°F recorded
at Entrican
weather station on Wednesday morning. Some farms have reported air temperatures
as low as 26°F though these reports have not been, and are difficult to
confirm. Low soil temperatures have been in the low to mid-50s.
Crop report
Alfalfa growth is
progressing; many stands are at 18 to 24 inches in height. Low levels of
alfalfa weevil damage have been observed with small larvae present. Growing
degree day base 41 (GDD 41) are near 600 at weather stations around the area,
and buds are present and swelling. Using the PEAQ stick confirms the ADF at
around 35 associated grassess especially orchard grass are heading out. Pasture
growth is rapidly maturing.
The majority of the corn
crop is planted. Early planted fields are at V2 to V3. Much of the crop has
emerged and is still somewhat pale green to yellow due to the cool
temperatures.
The majority of the soybean crop has been planted. Fields that were planted into good
soil moisture are emerging. A few early fields are at V2.
Wheat is in growth stage Feekes’ 9-10
with the majority in boot. Disease pressure remains low with powdery mildew
present in some varieties low in the canopy. The soils in many fields are
getting quite dry in the Montcalm area.
Oats are doing well in the cool weather
with good stands. Early fields are at Feekes’ 6-7. Many of these fields are
getting quite dry.
Very few dry beans have been planted as of today in the Montcalm area as soil and air temperatures remain cool.
Paul Gross
The cool and dry conditions are slowing crop progress. Soil temperatures remain in the low fifties. A little warm weather and an all day soaking rain would be just what the doctor ordered. Wednesday, May 28 in the morning there was wide spread frost with low temperatures reported at 29ºF. It is a little early to tell the extent of damage, but early reports are that there is minimal crop damage.
The corn crop is planted with 75 percent emerged. There are no reported problems at this time. Scout no-till and high residue fields for cutworm and other insects. Now is a good time to take the nitrate tests. With the high cost of nitrogen, it will be more important than ever to apply the proper amount of nitrogen for optimum yields. Contact your county Extension office for details.
Soybean planting is wrapping up. About 50 percent of the crop has emerged with the early planted field have the first trifoliate out. Growers are advised to get the herbicide applications on those fields that did not get adequate burndown. Waiting too long can result in yield loss.
The wheat crop is in the boot stage. Disease pressure is very light. The cool, dry weather is near ideal. If you are considering a fungicide application, time the application just prior to flowering to maximize crop protection.
Alfalfa harvest is well under way. No reports of serious alfalfa weevil feeding. Most are reporting average yields, but that varies from farm to farm. New seeding is doing very well.
Oats and barley crops are progressing very well with the cool weather.
Dry bean planting is under way and will continue as weather conditions permit.
Bob Battel
Temperatures warmed up over the weekend with mid- to upper 70s on Sunday, May 25, and low to mid-80s on Monday, May 26. We received spotty rain with most of the area receiving between 0.1 and 0.2 inches Monday evening. Temperatures turned cool again with a low of 31ºF recorded at the Pigeon weather station Tuesday night. The resulting frost has raised the question of crop damage, and we will wait for warmer temperatures to see if replanting is necessary.
Alfalfa harvest has not yet begun. Expect harvest to begin by about the beginning of next week.
|
Avoca |
704 |
|
|
663 |
|
|
611 |
|
Pigeon |
562 |
|
Chesaning |
560 |
|
Bad Axe |
559 |
|
|
535 |
|
Standish |
463 |
Again, a goal of 40 percent NDF is usually attained at approximately 750 alfalfa GDD from March 1, 38 percent NDF is attained at approximately 680 alfalfa GDD. Alfalfa GDD are different from corn GDD and calculated using a base of 41 degrees F from March 1.
Most wheat is either in the boot or beginning to head out. Disease and insect pressure is low.
Most corn is at the three to four leaf stage. Probably young enough yet that the cold temperatures received Tuesday night will not kill the corn, since the growing point should still be below the ground. Time and warmer temperatures will tell for sure.
Soybeans range from not yet emerged to the first true leaf stage. Keep an eye on soybeans that were just emerging or in the cotyledon stage at the time of the frost, especially in low areas for possible replanting.
Sugar beets continue to grow slowly and range between the four to six leaf stages.
Jeff
Andresen
Agricultural Meteorology
Geography
A strong area of high pressure centered over Lower Michigan
in the morning Thursday, May 29, will move eastward and give way to a
strengthening area of low pressure approaching from the central
Following the passage of the low pressure area Saturday, fair weather with seasonable temperatures is expected in most areas of the state Sunday and Monday. A second area of low pressure is expected to bring another chance for rainfall by Tuesday of next week.
In the medium‑range forecast period, a broad upper air
ridge across central sections of the
In our discussion of the new long lead outlooks, it is worth
taking note of the recent series of tornadoes and severe weather across the
There is some suggestion in the long lead outlooks that the
pattern so conducive to severe weather may gradually come to an end at some
point during the next several weeks. La Niña conditions in the Pacific are
expected to gradually diminish by mid- or late summer, which is reflected in
the new NOAA outlooks. For June, the outlook is linked to recent weather
patterns and to medium-range forecast guidance in suggesting cooler and wetter
than normal weather for nearly all of Michigan and other adjacent sections of
the Great Lakes region. For the 3-month June through August period, the outlook
for mean temperatures and precipitation totals remains in the climatology
scenario of near equal odds of below-, near- and above normal levels. The outlook
generally calls for