July 13, 2006
In this issue
§ Insect update
§ More information on mites
§ Asian soybean rust sentinel plot scouting report for July 6 to July 12
§ Soybean rust update
§ Wheat head scab and DON (vomitoxin levels)
§ Pythium and Phytophthora root rots of soybean
§ Maximum soybean growth stage for glyphosate applications clarified
§ Foliar fertilization of corn and soybeans
§ Soil Quality Field Day
§ Enhancing pollination and biological control with native plants
§ Regional reports
§ Weather news
Things have been manageable this year so far in the insect world, but there could be problems in the next few weeks associated with the tremendous variability in rainfall and crop height/ stage across the state.
Although first generation European corn borer numbers were generally low, corn fields that were late or replanted are at great risk for second generation infestation and should be targeted for scouting of egg masses. The threshold is 50% of plants with egg masses.
Corn rootworm beetles are emerging across Michigan, although root feeding is still occurring, as large larvae are present along with pupae. My impression, based on phone reports of damage as well as visiting fields, is that we may have heavy emergence and damage in many locations (including variant fields in southern Michigan). As the corn gets taller and summer storms move across the state, damage will become more obvious as plants lodge, but even fields that don't lodge may have significant rootworm feeding. With the variability in crop stage, adult rootworms will be attracted in August to late-planted fields that still have fresh silks. This could lead to heavy silk clipping (and impact on pollination) or to heavy egg-laying in these fields. In southern Michigan, variability in the landscape could also make late-planted soybean fields more attractive, leading to variant damage next season.
Japanese beetle adults have emerged in large numbers, and these also feed on fresh silks. As with corn rootworm adults, Japanese beetles will be attracted to late planted fields in August. In soybean, Japanese beetle defoliation is generally not a problem, but in corn, silk clipping from a combination of Japanese beetle and corn rootworm could pose a problem. Treat only if silks are clipped shorter than 0.5 inches before pollination occurs, and beetles are still feeding.
Potato leafhopper are described as being “by the sweep-net full’ in alfalfa. Leafhoppers can increase quickly in fields, and under dry conditions potato leafhopper damage is enhanced. In dry beans, numbers can increase dramatically when nearby alfalfa fields are cut. Potato leafhopper control is relatively easy – there are numerous products with 10- to 14-day residuals, the sampling methods are doable (sweep net or leaf counts), the thresholds are good, and potato leafhopper is not resistant to insecticides. The key is to scout fields and to apply insecticide at threshold. In organic production, Pyganic (a pyrethrum product) is registered for use in many crops, including alfalfa and beans. Although it provides good control of adults and nymphs, the residual is short. Thus, plants may be reinfested quickly by nymphs hatching from eggs. Frequent applications of Pyganic may be necessary.
Spider mite problems are spotty, occurring in areas that are dry and on sandy soils (southwest and central Michigan). Yellowing is a symptom of mite damage, although there are numerous other causes for yellow beans. Use a hand lens or tap leaves over a white piece of paper to confirm that mites are present in large numbers. Webbing on plants is a sign of heavy numbers. If problems are identified early, spot treatments may be possible, as mite populations often start on dry knolls or along dusty edges of fields. The threshold for treatment is 15% damage, based on percent yellowing, or use the rating system from Ohio State (see accompanying article in this issue on spider mites). Use an OP for control, as pyrethroids tend to flare mite populations.
Still no or few soybean aphids in Michigan and surrounding states. Suction trap catches of soybean aphid in Michigan are thus far all zeroes. Western Minnesota continues to be the only place with “sprayable” populations. Keep an eye out for winged aphids moving on storm fronts from this area - thus far we have not seen this flight.
Spider mites overwinter as adults. In spring, they move to new plant growth and lay eggs on the undersides of leaves.(see photo) Mites can be blown by wind, so initial colonization of a field will often occur in the direction of prevailing winds, or along landscape features that disrupt air flow, such as tree lines, houses or even telephone poles. Infestations usually start on dusty edges of fields. It is thought that dust dries the leaf surface, protecting mites from disease, or perhaps that the dust provides a surface for the mites to anchor their webs. With a hand lens or microscope, you can see that webbing acts like an interstate highway with mites moving back and forth above the leaf surface.
Eggs hatch in a few days and small mites begin to feed. Immature mites resemble the adults, except that they are smaller in size. They grow by molting, and if you look closely at a mite-infested leaf, you sometimes see the shed skins of immature mites. A leaf heavily colonized by mites will have eggs, immatures, adults, shed skins and webbing.
Spider mites feed on numerous crops, and under certain conditions, will increase to the point where they affect yield. This is especially true under dry conditions or on sandy soils where water stress is an issue. Mites pierce individual plant cells and suck out the contents, initially causing tiny yellow spots (called stippling) on leaves. This feeding also increases water loss from the plant. As populations increase, symptoms include yellowing of leaves, and in more severe cases browning, bronzing or death of foliage. As leaves become yellow and die from mite damage, the photosynthetic ability of the plant is reduced. With the additional water loss, leaf drop and reduced photosynthesis, yield and quality of crops is reduced by severe mite feeding.
If an infestation is identified early, spot treatments of the affected area plus a border strip may be enough to take care of mites. Otherwise, if mites spread across a field, the treatment threshold for dry bean is 25% of the plants infested with mites, with yellowing. For soybean, estimate the percentage of leaf surface damaged by mites. Treatment thresholds (based on % yellowing) vary with plant stage: pre-bloom = 40%; bloom R1 to pod fill R5 = 15%; R5 to early maturity R7 = 25%; after R7 = Do Not Spray. Damage at this point has little impact on yield. An alternative handy evaluation scheme (originally from Ohio State) for mites in soybean is printed in the accompanying table.
(Originally printed in the C.O.R.N. Newsletter)
|
Presence of mites |
Damage |
Assessment |
|
|
Barely detected on undersides of leaves in dry locations or on edges of fields. |
Barely detected. |
1 - Non-economic |
|
|
Easily detected on undersides of leaves in dry locations or on edges of fields. Difficult to find on leaves within the field. |
Foliage green, but stippling injury detectable on undersides of leaves, although not on every plant. |
2 - Non-economic, but keep monitoring |
|
|
All plants are infested when examined closely. |
All plants in field exhibit varying levels of stippling, even on healthy leaves. Some speckling and discoloration of lower leaves. Field margins and dry areas exhibit severe damage. |
3 - Rescue treatment is warranted, especially if many immatures/ eggs are present. |
|
|
All plants heavily infested when examined closely. |
Discolored and wilted leaves easily found throughout the field. Severe damage evident. |
4 - Effective rescue treatment will save field. |
|
|
Extremely high numbers. |
Field discolored, leaves drying down. Significant foliage and stand loss. |
5 - Rescue treatment may not save field. However, new growth may resume if treated. |
|
Mite control is difficult, and more than one application may be needed. Unfortunately, multiple applications are a losing proposition and can lead to resistance. Later in the season, spraying becomes more difficult due to closing of the canopy, and spraying is also less effective as plants mature (yield is no longer affected).
** Dry beans: dimethoate (0.5 – 1 pint/ acre). Will also control potato leafhopper.
** Sugar beets: Lorsban (1-2 pints/ acre)
** Soybeans: Lorsban (0.5 – 1 pint/ acre) or dimethoate (1 pint/ acre)
What about natural controls? A heavy rain may reduce the population a little, but don't depend on rain alone. The real key is high humidity, since the fungal pathogens that kill mites require high, sustained humidity to grow and spread through the population. A brief rain, followed by quick drying, does not provide a long enough period for diseases to spread and kill a significant portion of the mite population. Instead, you need a sustained rainy pattern, or repeated dewy wet mornings.
There were nine samples received from sentinel plots during this
reporting week. The following is a compilation of the reports.
Growth stages: 1 plot=V4, 1 plot=V5, 1 plot=V6-V7, 3
plots=R1, 2 plots=R2, 1 plot=unknown.
Plant height: Ranged from 10 to16 inches.
Degree of canopy closure: Ranged from 5 - 90 percent and averaged 60
percent.
Soybean diseases present: There were moderate levels of brown spot
(Septoria) present on samples from 4 plots. A sample submitted from Kalamazoo
County had downy mildew, this is the first time this season that we have seen
soybean downy mildew.
Risk levels for soybean rust in Michigan remain very low. So far this year, rust has been reported in 25 counties total, five each in Alabama and Georgia, 12 in Florida, one in Texas (the plot was destroyed earlier this year), and two in Louisiana. Only three of these reports have been on soybeans; the rest have been found on kudzu. The recent positive finds on soybean have been in Decatur County, Georgia (July 10) and Martin County, Florida (June 15).
Wheat is being harvested in the state with harvest approaching 80% completion in some of the southern areas of the state to around 25% in many other areas. So far, there have not been any reports of high levels of vomitoxin. In the next Field Crop CAT Alert, we’ll have an update of what has been reported.
Despite recent dry weather, growers may still be seeing evidence of root rot diseases in soybean fields, especially those that were very wet earlier in the year. Pythium root rot and Phytophthora root rot can develop in poorly-drained or saturated soils or soil that suffers from compaction. No-till areas with fine-textured soils tend to be favorable environments for these diseases, as the soil can become more easily saturated than coarser textured soils. The swimming spores, (called zoospores) need saturated soil to move to soybean roots to cause infection. Seedlings infected die rapidly, leaving gaps in rows. Soil temperatures in the range of 50 to 59°F are favorable for Pythium; Phytophthora needs warmer soil temperatures (around 68°F) for production of zoospores. Heavy rainfall resulting in flooded fields within a week or so of planting creates the most favorable conditions for infection. The symptoms are similar for both diseases. Young plants turn yellow, collapse and die, leaving gaps in row plantings. In plants that have reached more advanced growth stages, foliage wilts and turns yellow starting at the bottom of the plant and moving up. Dead leaves may remain attached. Lower stem discoloration starts near the soil line and spreads upward. Root tips and feeder roots are infected, causing root rots. Check plants in low areas or poorly drained parts of the field for symptoms.
It’s been mentioned several times on our Field Crop CAT Alert conference calls this year that this is a year when properly tiled fields will pay off. Improving drainage to remove excess water will reduce the duration and amount of soil saturation, creating a less favorable environment for the spores to cause infection. There is no genetic resistance to Pythium root rot, but there are soybean varieties with tolerance to Phytophthora sojae that would be worth considering for next year if you have had problems with Phytophthora root rot this season.
Recently, Monsanto has clarified the maximum stage for which glyphosate can be applied to Roundup Ready (glyphosate-resistant) soybeans. Currently stated on glyphosate labels, glyphosate can be applied from soybean cracking to “throughout flowering”. Throughout flowering is defined as the R2 soybean growth stage. The R2 soybean growth stage is where one of the two uppermost nodes on the main stem has an open flower. The R3 growth stage starts when one of the four uppermost nodes with a fully developed trifoliate leaf on the main stem has a pod that is 3/16 inches long. According to this definition, glyphosate can be applied through the R2 growth stage, but applications after the R3 stage begins will be off-label.
The clarification of this definition is important when making glyphosate applications to control late flushes of weeds or weed escapes in soybeans. These applications must be made prior to R3 soybeans. The clarification of this definition is also important with the trend for tank-mixing other pesticides, fungicides or insecticides, with glyphosate in soybeans. Many times the push to tank-mix these products is to clean up weed escapes in these fields and for the cost savings of a single application.
While a cost savings can be a fairly good reason to tank-mix these products it is important to remember that glyphosate can not be applied after the R2 soybean stage and that at this stage, insects such as soybean aphids, or diseases may not have reached threshold levels in soybeans to make the insecticide or fungicide application useful or economical. Additionally, if glyphosate applications are postponed until insects or diseases are at threshold levels chances are you will be off-label (past R2 soybean) or have already reduced your soybean yield due to weed competition.
Application methods also differ between glyphosate and insecticides or fungicides. Generally, glyphosate applications are made at lower pressures and spray volumes to reduce herbicide drift. However, for optimal control of insects or diseases, insecticides and fungicides are usually applied at higher volumes and pressures to increase coverage of the target species. With these considerations in mind, there probably will be very few times when it would be appropriate to tank-mix glyphosate with an insecticide or fungicide.
This time of the year we often receive questions regarding
foliar fertilization of row crops. Past research has shown that nutrient
deficiencies can sometimes be corrected with foliar applications, resulting in
a positive yield response. But in areas where there are no obvious deficiencies,
can foliar nutrient applications increase crop yields? Results of nationwide
studies have shown mixed results. Even where yield increases have been
observed, the level of yield increase often does not offset the cost of the
fertilizer and application. In 2003, Dr. George Rehm, extension soil fertility
specialist at the University of Minnesota, wrote an article in the Minnesota Crop News titled Foliar
Fertilization of Corn and Soybeans.
This article may be of interest to Michigan growers, and is a good example of
results found in similar studies. The full
text of the article follows with Dr. Rehm's permission.
Minnesota crop producers working for the extra yield have frequently considered the use of foliar application of fertilizer for both crops. Is this practice important? Does it pay? These are two of the frequently asked questions.
The concept of foliar fertilization has been researched for several years. Several projects focused on this management practice during the mid-1970's. More recently, there has been an intensive evaluation of in-season application of fertilizer - N for soybean production. Results of some of the research trials conducted in Minnesota are summarized in the tables that follow.
Application of fluid fertilizer containing N, P2O5, K2O and S was evaluated for corn production at the Southern Research and Outreach Center at Waseca. This mixture was applied 1, 2 or 3 times from mid-August through early September. Nutrients applied with each time of application were 25.3, 12.5, 6.3, and 1.0 lb of N, P2O5, K2O and S respectively. The results are listed in Table 1. All treatments received full N at 150 lb./acre as 82-0-0. In addition, there was a broadcast application of 60 lb. P2O5 and 100 lb. K2O per acre.
|
Time of fluid fertilizer
application |
Yield |
|
|
bu/a |
|
None |
131.2 |
|
8/13 |
135.9 |
|
8/13, 8/20 |
125.4 |
|
8/13, 8/20, 9/1 |
133.9 |
The application times were selected so that the fluid fertilizer would be applied during grain fill. The results of this study showed that foliar application of fertilizer had no positive effect on corn yield.
Following a report of a positive response of foliar application for a soybean crop, trials were conducted at three locations to evaluate the potential use of this management practice for soybean production in Minnesota. The fertilizer was applied during pod fill. The results are summarized in Table 2. There were two varieties at each location. Results were consistent with both varieties. Values in Table 2 are averages for the two varieties.
|
Nutrient applied |
Location |
|||||
|
N |
P2O5 |
K2O |
S |
Waseca |
Becker |
Rosemount |
|
lb/a |
|
|
|
bu/a |
|
|
|
0 |
0 |
0 |
0 |
57 |
53 |
59 |
|
40 |
4 |
12 |
3 |
56 |
54 |
57 |
|
80 |
8 |
24 |
6 |
59 |
50 |
59 |
|
80 |
8 |
24 |
6 + micros |
54 |
45 |
56 |
These results show that foliar fertilization is not a management practice that will increase soybean yield. Other universities throughout the Corn Belt conducted similar studies. The results were similar. Foliar fertilization had no effect on soybean yield.
There is a risk to foliar fertilization. The N could cause burning of the foliage and reduce yield. The yields summarized in Table 3 illustrate this risk. The N was applied as liquid urea to supply 75 lb. N per acre.
|
Treatment |
Yield |
|
|
bu/a |
|
Control (no N) |
45.1 |
|
Liquid urea (early bloom) |
42.4 |
|
Liquid urea (late bloom) |
37.6 |
In this study, the yield reduction from the late application of urea was caused by foliage burn.
Studies with in-season application of fertilizer N have been more extensive. In these trials conducted throughout Minnesota at 15 sites, there was a positive response to N at one site.
While the foliar application of fertilizer may seem like a logical management practice, this method of fertilizer application has not increased yield of corn and soybean in Minnesota. This practice is not recommended.
Dave Jacobs Farm, 7101 Henderson Road, New Lothrop, Michigan. Corner of Henderson and Vernon Roads in Shiawassee County, about 3 miles southwest of New Lothrop.
In 2003 the Crop and Soil Sciences Department at Michigan State University in conjunction with Agri-Business Consultants, Inc. received a grant from the North Central Sustainable Agriculture Research and Education (SARE) program to establish on-farm field studies to evaluate the effects of gypsum and lime application on soil quality and crop yields.
Share information learned in this SARE project and other programs designed to improve soil.
9:00 – 9:30 AM Registration and Refreshments
9:30 – 9:40 AM Welcome and Introductory Comments
9:40 – 10:00 AM Overview of SARE Project: Field Studies with Lime and Gypsum Applications
Attendees will be divided into small groups for presentations on Soil Quality Topics. Each presentation will be 30 to 35 minutes.
Station A. Gypsum and Lime Application: Affects on Soil Quality. Take a look at soil receiving gypsum vs. control soil. Darryl Warncke, Dept. of Crop and Soil Sciences, Michigan State University. Matt Duchrow, Agri-Business Consultants, Inc.
Station B. Improving Soil Quality with Manures and Crop Rotations. Integration of manure and residues for low fertilizer bills and more yield. Sieg Snapp, Kellogg Biological Station and Dept. of Crop and Soil Sciences, Michigan State University
Station C. Improving Soil Quality with Cover Crops. Learn the pros and cons of various cover crops. Do they fit with field crop production? Dale Mutch, District Extension Educator, Michigan State University
Lunch will be provided after the field day presentations and discussions are completed.
RSVP your attendance (for lunch count) to Darryl Warncke, 517-355-0271 x1270 or e-mail warncke@msu.edu by Wednesday, July 19.
Natural enemies and
bees need pollen and nectar to survive, yet many farms provide these resources
only during a few weeks when certain plants bloom. MSU is studying native
Michigan flowering plants that can provide these resources for farmers
throughout the growing season. Come to our August 1 Field Day to see the plants
and learn more about which ones are most attractive to natural enemies and
bees. Field day participants will:
§ Learn which plants have been identified through MSU research as the most effective at attracting beneficial insects. See additional native plants to be tested.
§ Learn which natural enemies common at native plants can help control your crop or garden pests.
§ Hear about seeding a prairie strip with hand broadcast and seed drill methods.
§ Visit a native plant nursery to learn about plant selection, seeding establishment, and maintenance.
To register, send $20 (for lunch, educational materials) check made payable to Michigan State University; your name, address, phone, and email to: Heather Lenartson, MSU Dept of Entomology, 243 Natural Sciences Bldg., East Lansing, MI 48824.
For more information, email Anna Fiedler at fiedlera@msu.edu or view details at http://ipm.msu.edu/plants/pdf/field-day06.pdf .
Can’t attend the field day? Learn more about native plants and beneficial insects at http://ipm.msu.edu/plants/home.htm
Weather has sure been different this summer. On July 3, some parts of Monroe County received over 3 inches of rain and other parts only 0.5 inch. This week 0.75 inches was very welcome, but some people received 2 inches and have ponding in their fields. Both May and June have had above normal precipitation.
Alfalfa is more than ready for a second cutting with the “early birds” getting this crop harvested prior to the rain. Potato leafhoppers have been over threshold and have caused much hopper burn. This insect will likely be a problem in the new stand.
Corn on July 4 was not tasseling and a few fields were not even knee high. Advanced fields are tasseling now and are beginning pollination. European corn borer trap counts are very low as they are between generations. Late planted or replanted corn will be magnet fields for second generation European corn borer. Japanese beetles are (everywhere) in cornfields and will be feeding upon the silks and tassels.
Soybeans are showing yellowing from root diseases and soybean cyst nematodes. One soybean aphid has been found this week. Japanese beetles have returned from low population years and are in large numbers feeding upon leaves, though damage is not economic. Farmers still have to apply post emerge herbicides to some soybean fields. We finally got the sulfur applied on a soybean plot this week and ahead of the rain.
Wheat harvest is nearly finished and stopped because of some rain Tuesday and Wednesday (July 12-13) this week. Harvest should finish up now that the rains have finished. Yields are in the hundred-bushel range; generally better than expected with confirmed yields ranging from 55 to 100, and an unconfirmed 135-bushel yield. Test weight has been good and lodged wheat has been able to be harvested okay. No reports of vomitoxin problems.
Land use and eminent domain is the hot issue down here involving farmland and a rail yard situation. Farmers are settling up for custom spring work, custom planting and wheat harvesting. Grain prices are encouraging with corn prices being the most volatile. The 2007 wheat prices have some farmers contracting bushels already. However, the big question today is whether the Red Wings will sign Ed Belfour.
Depending on where you are at, this last week’s rainfall was a lifesaver or a disappointment. Some of the western areas of the region have received only 0.6 to 0.8 of an inch of precipitation since early to mid-May. The normal temperatures have helped the drought stressed crops to tolerate the drought. Areas further to the east may have received 1.5 plus inches from the latest rain, which should help the crop to develop at a critical moisture period. With high temperatures in the forecast over the weekend, there will likely be severe stress on crops west of US-131 in many parts of southwest Michigan.
Early planted commercial corn is at Vt. Later planted corn is about 7 to 10 days out from initial pollination. European corn borer flight was extended and quite high in many portions of the region, which may mean somewhat the same situation for the second generation. Western corn rootworm beetles are beginning to emerge in the region. Japanese beetle numbers seem to be above normal this year. It may be prudent for folks to keep and eye on silk clipping activities, be prepared to treat when clipping is 0.5 inch of ear tips when silk are viable. In areas where you expect to see the rotation resistant variant of western corn rootworm, look for signs of windowpane feeding on corn leaves around the ear leaf as an indicator of beetle activity.
Despite significant early challenges with the weather, the seed corn crop is looking very good at this time. We have begun pulling tassels this last week and will be doing so for quite some time due to planting delays caused by early wet conditions. Some planned applications of fungicides are going on to protect the plants from rust and leaf blights. Many areas of St. Joseph County have received enough rainfall that irrigation has not been needed very often so far this year.
Most of the early planted soybeans look excellent in St. Joseph County. We have beans that are nearly waist tall in some fields with canopy closure and excellent yield potential. We do have a wide variety of challenges in soybeans this year though. We found twospotted spider mites in areas around Burr Oak, and they can be found in areas where it is dry west of US-131. Look for yellow spots that appear on the leaves that will eventually close in to form a distinctive bronzing discoloration of the leaves. Upon careful examination, you can often find webbing on the underside of the soybean leaves. Don’t expect to see spider mites with the naked eye, they are very small. If you have only small pockets in the field near an edge, it may be possible to spot treat. Plants are more susceptible when they are flowing and the thresholds are fairly low during the period from flowering to early pod set. There are several insecticides that are also active on spider mites. See Chris DiFonzo’s article on spider mites in this Field Crop CAT Alert for more information on controlling this pest. Japanese beetles are also beginning to feed on leaves. Soybean cyst nematodes can also be found on soybean roots in many fields. Look for small pearly white bumps on roots that appear about the size of small sand grains. We did confirm downey mildew in plant samples collected from the Kalamazoo County sentinel plot near Schoolcraft last week. Septoria continues to be prevalent in some sandy fields this year. I have not seen soybean aphids in fields that I have walked and the sentinel plots so far this year.
Alfalfa growth has been good but has been influenced by the rainfall that is extremely variable. Potato leafhoppers are heavy and can easily overwhelm smaller re-growth alfalfa. There is enough of a reservoir of leafhoppers out there that can readily move from one field to another that it would warrant most alfalfa producers to have at least some insecticide on hand to be able to treat with minimal notice.
The wheat crop may be one of the brightest spots for the western portion of the region. Wheat yields have been reported to be good in Berrien and parts of Van Buren County. Wheat yields have been somewhat disappointing in some irrigated fields in St. Joseph County. Moisture levels remained high in wheat for an extended period this year, which somewhat delayed harvest. Areas to the east may have challenges with the excessive rainfall that fell earlier in this week delaying harvest.
Much needed rain was received on Tuesday (July 11) and Wednesday (July 12). Some parts of Montcalm County received 2 inches while others received 4. Many crops in Montcalm County were showing signs of moisture stress until the rains. Newago County received 1.5 to 2 inches of rain with as much as 6 inches in some locations. High temperatures have been in the upper 70s to mid-80s.
Variable is still the word for corn. Tassel emergence is just a few days away for many fields. The past week was an excellent time to walk dryland corn fields to observe soil variability. The changes in water holding capacity was very evident in most fields. European corn borer trap counts are low.
Few
problems have been observed in dry beans.
Fields that were not treated at planting with an insecticide need to be checked
for potato leafhopper.
Soybeans are nearly as variable as the corn crop V3- R1 some
micro-nutrient deficiencies have been observed.
Wheat harvest is about to begin as a few growers have harvested small amounts. Grain moisture is still quite high, near 20% in many cases. Oats have turned and harvest will begin in the next week on early planted fields.
Harvest of second cutting of alfalfa is complete for the most part. A few folks are starting third cutting. Potato leafhopper numbers are quite high in many fields.
The region received varying amounts of rain early in the week. The amounts ranged from 1.25 to 5 inches. The region has received above average rainfall so far this growing season. We are at a time of year that we can handle greater amounts of rain. In some parts of the region, soils are saturated, and you can find water standing in many fields. The saturated soil conditions are causing root diseases in some crops. The rain along with the warm weather is excellent for crop growth.
The corn crop is beginning to tassel but we still have fields that the corn is just knee high. In some cases you can find both in the same fields. Variable best describes the crop. Some fields are excellent some poor. The crop seems to be healthy with few problems at this time. We are seeing some corn rootworm adults.
Soybeans are over a foot tall down to plants with the first and second trifoliate leaves. Most fields are variable as wet conditions have affected stands. We are seeing some root diseases. The populations of soybean aphids are non-existent thus far. In plots that are scouted weekly, we have not found one aphid. Continue to scout fields for this pest.
Wheat harvest is just getting under way. Early reports are that yield and quality are very good. We expect harvest to get into full swing as weather conditions allow.
Alfalfa harvest of second cutting is well under way. Yield and quality are very good. Harvest will resume as field conditions dry out. The population of leafhoppers is very high. Scout fields for this pest.
Sugar beets are progressing. Some stands are very good while others are spotty.
Dry beans are doing very good. Scout for leafhoppers and other insect pests.
Some areas have received near optimum rainfall and warm temperatures. These conditions have lead to great growing conditions. Other areas (some parts of Saginaw County) received near 5 inches of rain on Wednesday morning (July 12). Wheat growers are hoping for a break from the rain to resume harvest.
In sugar beets, Cercospera Leafspot has near optimum conditions for development with high humidity and extended leaf wetness. The Beetcast program is now showing DSV’s above 55 in many areas, which is the point the first fungicide application should be made to avoid significant early infestation. Positive identification of leafspot has been made in a few areas. Watch the Beetcast web site (www.Michiganbeets.com) for timely updates on this.
Wheat harvest has nicely begun in the Saginaw Valley but has been slowed by rainfall. Early harvested fields have shown good yields and good quality. Test weights have been measured above 62 pounds per bushel. Vomitoxin levels have not been a widespread concern.
Tassel emergence has occurred in many corn fields in the past week. Recent rainfall has helped to set up this crop to have a good pollination period. This should also help to alleviate stress from predicted high temperatures late this week. Plant health looks very good. Plant height appears to be shorter than normal.
Soybean growth has increased in the past 10 days to get some narrow row beans to canopy and many wide row beans are 75% canopied. Plant color has improved with significant nitrogen production. Overall appearance and health has improved since June.
Above-ground growth looks good in most areas, but root diseases are taking some toll on dry beans. Plant growth is rapid where plants are healthy.
The upper air ridging pattern than has been in place across much of the central United States for the past week will edge eastward over the next several days, setting the stage for a series of hot and humid days across Michigan though the upcoming weekend. A few scattered showers will be possible Friday through the weekend across far northern sections of the state, otherwise dry conditions are expected. Temperatures will increase to much above normal levels for the next five days with means running 5 to 10 degrees F above the climatological normals. High temperatures will reach the mid to upper 80s over most locations Thursday, increasing into the 90s over much of the state Friday Saturday and Sunday. High temperatures may approach the 100°F mark across sections of the western and central Upper Peninsula Friday and Saturday. Lows temperatures will increase from values in the low to mid-60s Friday morning to a range from the mid- and upper 60s north to the low 70s south this weekend. A cool front is expected to approach the region by Monday of next week with the next chance for significant precipitation, followed by somewhat cooler temperatures by the middle of the week.
A new pattern is beginning to emerge in the medium range forecast guidance with a split flow upper air pattern suggested over North America. This would result in more seasonal temperatures across Michigan and the Great Lakes region. Both 6-10 day and 8-14 day outlooks from the NOAA Climate Prediction Center (covering July 18-22 and 20-26) now call for near normal temperatures state- and region-wide. Precipitation totals during the 6-10 day time frame are forecast to remain at near normal levels. During the 8-14 day period, the forecast calls for rainfall totals to increase to above normal levels across the state.
The rainfall event of this past Tuesday evening brought much needed moisture to parts of western Lower Michigan. Unfortunately, many areas that really needed the rainfall were missed (e.g. the western Upper Peninsula and portions of western Lower Michigan along I-94). As of early July, soil moisture levels across the state range from excessive to abnormally low thanks to a highly variable rainfall pattern since early April. Figure 1 depicts precipitation departures from normal across the state during the past three months based on a combination of observed station reports and NEXRAD radar precipitation estimates. Departures range from more than 6 inches above normal in west central and central sections of Lower Michigan to more than 6 inches below normal in western sections of Upper Michigan (see Figure 1). For climatological perspective, normal accumulated rainfall for this period ranges from just less than 8.0 inches over northeastern sections of the state to more than 10.0 inches over the southwestern Lower and western Upper Peninsulas. Based on the short range outlook, the precipitation and soil moisture deficits in some western sections of the state are a growing concern, especially over western Upper Michigan.