On July 26, soybean rust was confirmed on soybeans from a sentinel plot in Rapides Parish, Louisiana. This is the first report of rust on soybeans in Louisiana for the 2006 season. So far this year, rust has been confirmed on soybeans in six different counties in four states: Alabama, Florida, Georgia and Louisiana. The rest of the finds have been on Kudzu – 26 counties in five states: Alabama (5), Florida (12), Georgia (5), Louisiana (3) and Texas (1). The movement of rust to other areas has been slow this year due to dry to very dry weather in spore source regions. Last year at this time, there were 14 confirmations of rust in Florida, Georgia, Alabama and Mississippi.

There were 8 samples received from sentinel plots during the reporting week.

The following is a compilation of the reports.

Growth stages: 1 plot=V6, 1 plots=R1 ®R2, 4 plots=R2, 1 plots=R4, 1 plot=unknown.

Plant height: Ranged from 11 to 30 inches with 1 height unknown.

Degree of canopy closure: Ranged from 50 ® 100 percent, 1 unknown, and averaged 89 percent.

Soybean diseases present: Samples had high levels of Septoria and moderate levels of bacterial blight.

At what point in the growing season is corn grain yield determined? Well, of course it involves the continuous interaction of genetic, climatic, soil, plant pest and nutrient factors present for a specific growing season. However, from a crop management standpoint, it is helpful to characterize the most critical stages of development in the life of a corn plant with respect to determining final grain yield. Following are four critical stages in the development of a corn plant that are fundamental to determining corn grain yield.

The first of these critical stages is emergence. Corn does not have the ability to compensate for poor stands as well as other crops such as soybean. Establishing a uniform, optimum population stand is the first step in developing corn grain yield potential. Studies on the genetic evolution of corn indicate that modern hybrids tolerate field stress associated with higher plant populations better than their earlier genetic predecessors. Growers should continually evaluate the carrying capacity of their fields by putting in a few strip trials to determine the optimum plant population for each field. Keep in mind that as corn genetics continue to evolve, you will likely need to continually adjust your planting population upward to find that optimum plant population for each field. The 2006 planting season will be remembered for highly variable stand establishment. Areas with good drainage generally came through with good stand emergence. Conversely, areas with poor drainage suffered significant stand loss.

The second critical growth stage is when the plant determines the number of kernel rows and the number of potential kernels (ovules) per row. This is primarily determined during the rapid phase of corn vegetative growth, which generally occurs in early to mid-July in Michigan. The number of kernel rows per ear is heavily influenced by genetics and is generally determined by growth stage V12, which corresponds to the 12 leaf collar stage. The number of potential kernels per row is being determined at V12 and is usually completed a week to 10 days prior to silking (V17). The number of potential kernels per row is strongly influenced by field conditions. Managing corn to reduce environmental, pest, moisture and nutrient stress during this time will maximize the potential number of harvestable kernels. Follow a plan to ensure adequate nutrient levels and minimize stress from pests such as weeds and insects during this critical period to establish the potential for high yield. Most of the state came through this stage of development in great shape. Adequate soil moisture during the vegetative growth stages across much of the state has set the stage for good corn grain yields this fall.

The third critical stage is pollination. Successful pollination is required to convert potential kernel numbers to actual developing kernels. Pollination occurs when a pollen grain is shed from the tassel, lands on an emerged silk, grows down the length of the silk and successfully fertilizes the ovule. It generally takes two to three days for all the silks on an ear to be exposed and pollinated. Pollen shed generally occurs in the late mornings and early evenings and the pollen shed period typically lasts from one to two weeks. From a management perspective, there is not a lot that can be done to ensure good pollination since it is highly dependent upon the weather. Droughty conditions can de-synchronize pollen shed and silk emergence and also can desiccate silks and pollen grains. This results in barren ears or in short ears with barren tips. Insect pests such as adult corn rootworm beetles can feed on emerging silks and reduce pollination and therefore should be scouted during silk emergence. Finally, because the tassel and all leaves are completely exposed, the plant is especially vulnerable to hail damage at this stage. We are currently in the midst of the pollination stage of corn in much of the state. At this point, it appears that we should be in great shape for maximizing corn grain pollination.

The final critical growth stage for determining corn yield is the grain fill or kernel development period. The grain fill period which begins at pollination and ends at kernel black-layer formation generally takes from 60 to 70 days (855 to 1200 GDD) for Michigan conditions depending upon climate, planting date and hybrid relative maturity. The size and weight of harvested kernels are determined at this time and under adverse conditions kernel number can also be reduced. Stress on the corn plant during the grain fill period can affect final yield by reducing either of these factors. Although field and machinery conditions can still influence final harvestable yield, the corn plant photosynthetic factory has completed its work at the kernel black-layer formation stage of development.

Annual weed densities are very high in wheat stubble this year. These weeds must be managed soon in order to prevent seed production. Several effective options are available for management of annual weeds in wheat stubble. However, these practices must be implemented before seed production to avoid significant additions of seeds to the weed seed bank.

After wheat harvest, weeds take advantage of available resources, especially newfound sunlight, and will grow rapidly, especially in years with adequate soil moisture in July and August. These weeds are capable of producing large amounts of seed prior to a killing frost.

Common ragweed, velvetleaf, common lambsquarters, redroot pigweed and foxtail species are examples of common summer annual weeds in wheat stubble. At this time of the year, these weeds are completing their life cycles by flowering and producing seed. The main goal following wheat harvest is to prevent or reduce weed seed production. Post-harvest weed control options include tillage, mowing and herbicides. In general, management of annual weeds in wheat stubble is not difficult, however timeliness is critical.

Tillage is a viable option for control of both broadleaf and grass weeds. Mowing will reduce seed production of most grass and broadleaf weeds. However, mowing is often less effective on grasses since seeds can be produced on tillers low on the plant. Glyphosate and 2,4-D are common herbicides used for post-harvest weed management in wheat stubble. Refer to the herbicide labels for appropriate rates, adjuvants and tank mixes.

Earlier this season in St. Joseph County, a farmer found out the hard way that yews (Taxus spp.) are extremely toxic to cattle. A few overgrown bushes were removed from a landscape one afternoon and pulled into a pasture area. The intention was to burn them once all were removed and dried. The next morning, all 10 cattle in the pasture were dead. Plant material submitted to the lab was identified as Japanese yew (Taxus cuspidata).

Taxus is the genus that includes numerous forms of evergreen shrubs or trees used in the landscape. Common species include Canada yew (T. canadensis), English yew (T. baccata), Japanese yew (T. cuspidata) and Anglojap yew (Taxus x media). Cultivars of the Anglojap yew, a cross between T. cuspidata and T. baccata, are some of the most encountered at garden stores.

Yews have linear, sharp-pointed, approximately one-inch long, needle-like leaves that are dark green above and yellow green below. Leaves are spirally arranged but generally lie flat on the stem. Flowers are inconspicuous with mildly attractive, red, berry-like fruit.

All parts of yews, except the red, fleshy part around the seed, are extremely toxic to cattle and other livestock. The primary toxin is taxine, which is a mixture of alkaloids that act upon the heart and usually result in death of the animal. Uprooted bushes and clippings should never be placed near livestock. Yew is generally not highly palatable to livestock. However, animals are more likely to graze on tender new growth or clippings discarded in a pasture. As little as a mouthful to 1 lb. of yew clippings is sufficient to kill a 1000 lb. animal in only a few minutes.

Ingham County MSU Extension will host an August 10 program for those who have considered beginning or transitioning to organic or "natural" agricultural production.

The tour, organized by Dan Hudson of Ingham County Extension, will begin at 8:00 AM, after which a chartered bus will depart from the Mason Meijer on Kipp Road and take participants to several types of operations, including: farms focused on organic field/horticultural crop production and organic (meat/egg) production, an organic dairy, a community-supported agriculture (CSA) operation and several family-owned and cooperative businesses that market their organic products.

This program will give prospective organic or "niche-seeking" agricultural producers a chance to learn more about organic farms. An organic box lunch will be provided when the group stops at a township park on the Grand River.

The bus will return to Mason at about 5 p.m. The cost of the tour is $25 and the tour is limited to 55 people. For more information, call (517)676-7207 or e-mail cvernon@ingham.org

3 -- West Central
Fred Springborn

Weather
We have had measurable rain fall 7 out of the last 14 days in Montcalm County. High temperatures have been in the upper 70s to mid-80s reaching nearly 90° on three days of this two week period.

Commodity reports
Corn pollination is in progress or complete in the majority of fields. Soil moisture is generally adequate. European corn borer trap counts are low.

Dry beans are in bloom and setting pods. Few problems have been observed in dry beans. Fields that were not treated with an at-planting insecticide need to be checked for potato leafhopper.

Wheat harvest is continuing. Few good threshing days have been available over the past two weeks. There have been reports of sprouts in wheat. Vomotoxin levels have been low. Oat harvest has begun with good yields observed. Lodging is a difficult harvest issue for many oats fields.

Harvest of dry hay has been an unusually big challenge for late July. Potato leafhopper numbers are quite high in many fields.

5 -- Thumb
Mark Seamon

Weather
Some areas have received near optimum rainfall and warm temperatures while other areas would appreciate a short break from the rainfall.

Commodity reports
Cercospera leafspot continues to be the main concern among sugar beet growers. The beetcast leafspot prediction system is recommending a fungicide application to prevent Cercospera infection. Some areas are nearing 100 DSV’s which is approaching the 55 + 55 (or 110) DSV system for timing of a second application. Watch the BEETCAST web site (www.Michiganbeets.com) for timely updates in your area. Water damage is showing up in areas that have ad saturated soil for too long.

Wheat harvest is wrapping up across the Thumb area. The earliest harvested fields showed the best quality while later harvest showed significant sprouting and lower test weights. Growers who plan to use saved seed for fall planting should have a germination test done since sprouted wheat can be misleading for some basic germination analysis.

The corn pollination period was not perfect with some areas having too much soil moisture and temperatures in the 90s, but plant stress was minimal. Pollen shed in the morning should have been adequate to pollinate the ears. Most of the Thumb is on track for a very good corn crop.

Most soybeans look good. The areas that received excess rain are showing some problem areas in soybeans where water ponded or the soil was saturated too long. These yellow areas are showing signs of lack of oxygen to the roots and death of nodules. These may recover significantly if soil moisture is adequate near the surface where new roots are regrowing.

Some dry beans look grea,t while others are showing stress form excess soil moisture. Recent weather conditions are near ideal for flowering and pod formation. White mold must be considered for this same reason.

A mostly west to east zonal jet stream is expected across North America for much of the upcoming week, with the passage of several weak weather disturbances through the Great Lakes region. Given good low-level moisture inflow from the south, this weather pattern should lead to very summer-like temperatures and an almost daily chance of scattered showers and thunderstorms through the weekend.

Rainfall chances over the next few days will be best during the late afternoon and early evening hours when atmospheric instability is greatest. Precipitation totals through the weekend are expected to be highly variable by location, ranging from less than 0.25 inches in some areas to 1.0 to 2.0 inches in others. Heaviest precipitation is expected across northern sections of the state. Temperatures will increase to much above normal levels for the next seven days with means running 6 to 10 degrees F above the climatological normals. Much of this departure from normal will be associated with abnormally warm nighttime temperatures. High temperatures during the next several days will generally warm from a range of near 80° in far northern lakeshore areas to near 90° in the south on Friday, then into the 90s by early next week over most sections of the state. Lows are expected to range from the upper 60s north to the low 70s south. With dew point temperatures remaining near 70°F through early next week. Heat index values will likely approach 100 by Monday.

In the medium range forecast, latest guidance suggests upper air ridging over the central United States with troughing over New England and over the Pacific Northwest. The forecast pattern is similar for both 6-10 and 8-14 day periods, although the central ridging feature is expected to be flatter (more west to east) in the 8-14 day time frame.

Both 6-10 day and 8-14 day outlooks from the NOAA (covering August 1-5 and 3-9) call for above normal temperatures state- and region-wide. Precipitation totals during the 6-10 day time frame are forecast to remain at near normal levels statewide. During the 8-14 day time frame, precipitation totals are forecast to fall back to below normal levels.