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.

Watch for today’s USDA Supply and Demand Report to provide some yield estimates that will take the flooding into account. USDA last estimated corn at 149 bu., based on the slow planting rate, but not on lost acres or ponded fields. Soybean yields will get some attention, based also on acreage, but little on plant development and maturity.

The yield and production estimates from the July report will figure prominently in the market moves over the next few weeks, says ag economist Chad Hart at Iowa State. “Another yield adjustment in corn could push estimated production below 11.5 billion bushels, well below last year’s record production. This would tighten the outlook for corn as projected usage was already above estimated production and similarly for soybeans.

Regarding beans, even at trend yields, if demand holds as projected, 2008 ending stocks could approach 100 million bushels, below the carryout projected for 2007. Any sort of downward yield adjustment would continue to tighten an already tight market.

Have you looked inside a corn whorl lately? That is the home to a wide range of bugs that are defoliating corn from the inside out. Unfortunately, Extension entomologists in the Cornbelt agree that little is known about such an impact, and have had to use data from hail defoliation to provide insight about how badly corn can be damaged.

Corn growers and researchers have found whorls to be harboring fall armyworms, Japanese beetles, and first generation European corn borer. Specialists say the winter did not increase their mortality, and the delayed planting and delayed corn development this year have synchronized V6-VT stages of corn with a host of defoliating insects.

So what do you do? Specialists say the defoliation looks worse than the effect it will have on yields. Species should be identified and evaluations made of their damage, which they add, tassel destruction is not an issue. But silk clipping needs to be monitored. Find out more.

High valued corn is even in more jeopardy from silk clipping insects, such as Japanese beetles and corn rootworm beetles. “An insecticide application may be warranted when there are 5 or more rootworm beetles per plant, pollination is not complete, and silk clipping is observed. An insecticide application may be warranted when there are 3 or more Japanese beetles per ear and pollination is not complete. Entomologists say the numbers of Japanese beetles may be overwhelming, but just protect the corn silks.

Late planted corn and beans may be hosting black cutworms. Normally they hurt young corn, but this year, the late planted fields are giving them a second wind. Crop scouts report the population of a replanted soybean field was clipped about 50%.

Western bean cutworms are becoming prevalent, and spreading quickly across the Cornbelt and even into Ontario, Canada. IL Extension entomologists say they are apparently replacing many of the insects killed off by YieldGard and Agrisure. So it seems that the western bean caterpillars are not hurt by those Bt genes. They say the Herculex Insect Protection products are an alternative. If an insecticide is needed, the determinant is when 8% of the plants are infected before larvae move to the ears.

Soybean aphids remain in relative seclusion or in very small numbers that have escaped crop scouts. Some discoveries have also found predators along with the aphids that have helped keep populations down. However, IL Extension entomologist Kevin Steffey says temperatures from 70 to 86 degrees will allow aphid populations to double in 3-4 days.

Is there a need to spray soybeans with a foliar fungicide? X.B. Yang at Iowa State says, “This year would be the year to see the benefits unless we are fooled by Mother Nature and the rest of season becomes hot and dry.” He adds, “The chance to see yield benefits from a spray so far is much higher than most normal years.”

Is there a need to spray soybeans with a foliar fertilizer? Agronomist Antonio Mallarino says, “The short answer is that it may, but probably not in fields that have been well fertilized or where growth is limited by factors other than nutrient supply.”

If your county was one of those in which USDA released the CRP for early grazing, you need to evaluate the benefit of the additional pasture with the fact that your CRP rental payment will be reduced by 25%. That calculation will also have to include the cost of fences and water supply for the livestock. A modified conservation plan must be submitted, and the FSA office must approve the plan. Find the list of states & counties.

If you can wait until August 1, you can either graze or bale hay on your CRP for only a nominal fee. Iowa State agronomist Stephan Barnhart says most CRP is going to have weeds and brush along with any grass that will reduce the value of the hay and could damage baling equipment. He says the nutritive value of the crop is low, because plants have now begun to lose their protein content and have begun accumulating fibrous tissue.