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The number of acres planted to cover crops annually has been steadily increasing in recent years throughout the United States. Meanwhile, the soybean cyst nematode (SCN) continues to sit atop of the U.S. list of yield-suppressing pathogens. It’s no coincidence, then, that there is an increasing interest regarding the potential for these two factors to interact in the field, particularly with the possibility that cover crops could decrease SCN population densities (numbers).

There have been many reports of corn along the edge of the fields yielding drastically less than the remainder of the field. In many cases, the yield loss is most obvious on the southern edge of the field, but it has been observed along the west, east, and north sides of fields this year. This has left many growers wondering what caused this. Some hypothesized causes are herbicide drift or an edge effect from the hot, dry winds and stressful conditions this summer.

Up to this point in the harvest season we have been short on grain dry down and cooling weather. Corn moisture percentages have been hanging in the 20’s, sometimes in the upper 20’s. This past week eliminated much of the moisture, but favorable field dry down weather rarely continues into November. Farmers should now focus their attention on cooling, both of wet corn in holding or air dry situations, and of dried corn being removed from dryers. Inadequate or delayed coolin

I’ve received lots of inquiries in the past few weeks about sampling fields for nematodes that feed on corn. Most every Iowa field has one or more different nematode species present at low numbers. But it’s only when numbers are at damaging levels that yield loss will occur.

I grew up watching the television show Quincy, M.E.  Jack Klugman starred as a Los Angeles County medical examiner in the mystery-thriller, one-hour show as Quincy who had to solve mysterious deaths.  I would argue this show set the tone for future shows such as "CSI: Crime Scene Investigation" and "NCIS".  These shows lead us to believe we can easily solve crimes and determine the cause of death. 

Over the past couple of weeks we’ve been doing stalk rot assessments at several of the ISU Research Farms including the Southeast Research and Demonstration Farm, the McNay Research Farm, and the Ames Farm. While the plants seemed to be standing well, minus where the raccoons had fun in one of the trials, it was not uncommon to find stalk rots in the plants we sliced open to evaluate.

If you would like to learn more about current soil fertility issues and research being conducted at universities across the North Central region, then consider attending the 47th Annual North Central Extension-Industry Soil Fertility Conference to be held November 15-16, 2017, from 1:00 p.m. to noon, at the Holiday Inn Airport in Des Moines, Iowa.

This week, my technician Greg VanNostrand found a black widow in our storage Quonset at the ISU Johnson Research Farm. The farm is just south of Ames in Story County. She is an adult female and had a pile of dead body fragments below her web. Needless to say, she was healthy and happy in the Quonset. But Greg likes spiders and decided to bring her back to my lab (thanks?). He has successfully kept black widows (and other spiders) by feeding them flies from colonies in the Insectary.

Often people have fond memories of monarch butterflies and look forward to their arrival each summer. But there is some confusion about their migration pattern and population decline. “How can such a tiny butterfly travel such a great distance?” and “What do you mean the population is declining?” are common questions that are asked at educational events.

As the 2017 growing season winds down, ISU Extension and Outreach field agronomists share how the crops are progressing and finishing out the season in their repressive regions across the state.   

Northwest Iowa

I’m getting a lot of questions regarding treatment timing for soybean aphid. Mainly, when is it too late to treat? In the last week of August 2017, most fields are reaching R5/R6 and so the question is an important one. In my soybean aphid efficacy evaluation, I have sprayed at different plant growth stages to evaluate yield responses. I have never been able to demonstrate a yield response when spraying after R5.5.

The economic threshold of 250 soybean aphids per plant, with more than 80% of plants infested and aphid populations increasing was published in 2007 to prevent populations from reaching the EIL.

Iowa State University Extension and Outreach field agronomists report crop conditions in NW, NE, and SE Iowa. 

The following article originally appeared on the ISU Weed Science Online website.  Current research is showing that the new formulations of dicamba (Xtendimax with Vapor Grip Technology and Engenia) have not solved the volatility problem associated with dicamba.  Since the fundamentals of chemistry have not changed, the research done with older formulations can provide insight in explaining problems experienced during 2017.

 #Drought17, late season hail damage, weed escapes, and soybean aphids seem to be the big issues ISU Extension field agronomists are seeing in fields across the state this past week. Read on for more information about your region's crop progress and field conditions.

Seeding Cover Crops in Dry Conditions

The dry and droughty conditions, spider mites, soybean aphids, and dicamba drift are common issues ISU Extension field agronomists are seeing across the state. Read on for more information about your region's crop progress and field conditions.

Northwest Iowa

Rainfall continues to be scattered across the state. According to the U.S. Drought Monitor, 64% of the state is abnormally dry, 34.7% is in a moderate drought, and 1.6% is in a severe drought. ISU Extension field agronomist share what they are seeing in their respected areas across the state.
 

U.S. Drought Monitor as of July 25. Source:http://droughtmonitor.unl.edu/. 

Northwest Iowa

We’ve got the terrible too’s in weather extremes across Iowa. Parts of northeast Iowa received too much rain and experienced flash flooding while many other parts of Iowa are in desperate need of rain and have seen too little rain. Iowa University Extension and Outreach field agronomists share crop reports on what they are seeing in their respected areas of the state.   

As of February 2017, Palmer amaranth (Amaranthus palmeri) had been found in 49 of Iowa’s 99 counties.  A native of the American southwest, Palmer amaranth is more competitive than common waterhemp (Amaranthus tuberculatus), a pigweed native to Iowa.  These two species are two of the most troublesome for corn and soybean farmers.  Both species are known for fast development of herbicide resistance, incredible seed production on female plants (>500,000 seeds