Extension Update is a weekly summary of news from Extension, government, and other attributable sources, focused on marketing, farm management, and other issues that are of interest to Midwestern farm owners and operators.

Corn market dynamics are numerous says IL Extension’s Darrel Good, who notes increased wheat feeding has reduced corn demand. USDA recently reported lower demand from corn refiners because of high prices, which may keep corn short of the 3.95 bil. bu. forecast use by ethanol refiners. But, lower prices have strengthened margins. Read more.

Darrel Good says corn crop condition ratings continue to improve, and the average yield could climb 2-3 bu., even with just average weather for the rest of the growing season. USDA’s first field forecast will be released Aug. 12, and maturity is so late, yields will be hard to guess. But that report will also have updated estimates for harvested acreage.

The Illinois crop weather model puts soybean yields a bushel higher than USDA’s June estimate of 41.6 bu. if the weather is average for the rest of the season and there is not an early freeze. Good says the late planting and all of the replanting make production estimates difficult and the Aug. 12th report will be more valuable for its acreage numbers.

$529 per acre. That is the estimate for corn production costs next year, and that does not include land costs such as cash rent. Extension economist Gary Schnitkey says fertilizer prices have nearly doubled per acre, and that is helping push soybean production costs to $321 per acre, also just the non-land costs. Read the details in his latest newsletter.

Two things are flying over corn fields. Japanese beetles are metallic green. Air Tractors are yellow and usually have a cloud of fungicide trailing them. If you think you need one, scout your field to determine the presence of any fungal disease, and check your hybrid for its resistance level. If it is susceptible, then call an aerial applicator.

Fungal diseases in corn can be one of several say Ohio State specialists
1) Gray leaf spot is tan to brown, 3-4 in. long, and fits between leaf veins.
2) Northern corn leaf blight is gray/green to tan, 1-6 in. long and cigar shaped.
3) Eye spots are round to oval, 1/8 in. across, watery first, then tan to cream colored.
4) Common rust creates dark reddish-brown, elongated pustules, less than ¼ in.

The goal for fungicide application is timeliness. It should be applied before the ear leaf and the leaves above the ear are infected, since they provide 75% of the carbohydrates to fill the kernels. Due to the movement of the fungus, the fungicide should be applied when the first few lesions are observed on the leaf immediately below the ear leaf. Due to the variability in crop size and maturity, more than one application may be needed.

Japanese beetles don’t care about crop values, so manage judiciously. For soybeans, it only takes one bushel of damage to pay for an acre of crop protection. The published economic thresholds for all soybean defoliators is 30% defoliation before bloom and 20% defoliation between bloom and pod fill. Lower thresholds are still being researched.

The Midwest bug roundup has found relatively few problems this year, other than Japanese beetles in scattered swarms. Extension entomologists compared their notes:
1) Western bean cutworms are being found in all states,
2) Soybean aphids are common, but not numerous, and very low in the Eastern Cornbelt.
3) Very large numbers of armyworm moths are being captured in some traps.

How many corn rootworm beetles does it take to screw in a light bulb? If that bulb is your bright idea of scouting this year to protect your 2009 corn crop, then it only takes .75 beetles per plant in continuous corn and .56 beetles per plant in first year corn. That is the estimate of Bob Wright of NE Extension who bases that on 24,000 population. For 32,000 population the threshold is .56 beetles for continuous corn and .42 for first year.

If treatment thresholds for corn borers were established when corn was $2.50, what would be the threshold for $7 corn? Iowa State Extension’s Jon Tollefson looked at both $6 and $7 corn, and control costs of $15 and $18 per acre and prepared a decision aid.

Brown spots on soybean leaves do not necessarily mean soybean rust, but may prompt you to apply a foliar fungicide. However, IL Extension’s Carl Bradley says not all of the fungal problems will cause large yield decreases, and some cannot be controlled with a foliar fungicide. Read more.

Foliar soybean diseases need to be identified before any foliar fungicide is applied:
1) Septoria brown spot can be controlled, but does not always cause yield loss.
2) Frogeye leaf spot can be controlled, but does not always cause yield loss.
3) Downy mildew cannot be controlled with a foliar fungicide.
4) Bacterial blight is caused by a bacterium, and is not controlled with a fungicide.

For years, you have been applying atrazine to kill grass in corn. But researchers at Iowa State say a ground cover, such as grass, may benefit corn. They are not sure what kind of grass and how much, but their theory is to create a mulch that will preserve soil and soil moisture, return carbon to the soil, keep down weeds and insects, and maintain yields.

Maybe you don’t want to know, but now is the time to dig up some soybean roots and count the number of female soybean cyst nematodes. Don’t count the root nodules, but the white spots about the size of a period at the end of a sentence. If your beans are more than four to five weeks old, satisfy your curiosity and check out this crop stressor.

Mark your calendar for Agronomy Day, Aug. 21 at the Univ. of IL South Farms. All details are here and the Urbana tour topics include:
1) Corn nematodes, returns to fertilizer, soybean resistance genes, & soybean yields.
2) Ethylene, managing wheat scab, soybean aphids, & managing pests in corn.
3) Residual herbicides, waterhemp, giant ragweed, and utilizing fertilizer value in manure
4) Corn stover, biofuel impact on soil, biomass feedstock, & bioenergy markets

“Full season weed control” is a luxury, since you only need enough for your corn to reach the canopy stage, says Bob Hartzler at Iowa State. Before spraying full sized corn, evaluate your weeds, which should be at a disadvantage to the corn. “Research at ISU found that less than 1% of the waterhemp emerging at the V8 corn stage survived.”

Lower corn prices have been helpful to cattle feeders, says economist Dillon Feuz at Utah State, who also says calf prices have strengthened. But he says fall and winter cattle prices have declined in the past two weeks. “With present feed prices, feeder prices, and expected fed prices, there still is not much if any money to be made feeding cattle.” He says cattle prices will probably continue to decline as long as corn remains above $6.

Fourth quarter hog slaughter is being forecast higher than last year by MO economists Glenn Grimes and Ron Plain, who say packers will have to operate at all time high efficiencies, with the hope of averting a fire or strike and approaching the 1998 lows. “Do we expect $10 per cwt hogs this year? No, could it happen again? Definitely.”

The days may be numbered for PRRS virus, and that makes pork producers happy. IL vet med research has received a $400,000 federal grant to genetically engineer mutant PRRS viruses to create a vaccine for pork producers to use. Researchers have also discovered how such a vaccine could also immunize hogs against the porcine circovirus.

You are baling wheat straw and you suddenly break out in a cold sweat of concern about all of the nutrients you are taking out of the soil. IL Extension fertility specialist Fabian Fernandez appears surreally in your tractor cab and says, “Don’t worry; there are ways of calculating the fertilizer value and estimating the true cost of straw removal.”

Fabian Fernandez at the University of Illinois offers a method of nutrient calculation:
1) Calculate how much straw is produced, based on 1 lb. of straw per 1 lb. of grain.
2) Determine how much straw is actually removed from the field, such as 2.5 tons/acre.
3) 1 ton of straw will contain 9-12 lb. N, 3-4 lb. P, and 25-40 lb. of K.

Speaking of wheat stubble, is yours weedy? You don’t want the weeds to go to seed in the next few weeks, so mowing and herbicide applications are the choices. For a spray, Mark Loux at Ohio State says use glyphosate at 0.38-.75 lb. of a.e./acre blended with
2, 4-D at .5 lbs. per acre. Your objective is to prevent weeds there next year.

Producing biomass for an ethanol plant, your choice would likely be corn stalks instead of switchgrass. Purdue economist Wally Tyner says corn stover costs $40 per dry ton delivered, versus $60 for switchgrass. Corn stover will produce $80 per acre profit in addition to the corn crop. Switchgrass would produce a total profit of $160 per acre.