Blog

Check out what ISU Extension and Outreach field agronomists in EC, SE, and SC Iowa are seeing and hearing in their areas regarding crop progress and issues showing up in crop fields.

Update on crop and soil status across the I-states – August 21, 2019

Farmers and agribusiness are invited to the Allee Demonstration Farm for a field day on Tuesday August 27.  Coffee and registration will be at 9:30 with a free lunch at noon.  

The Allee Research Farm is located at 2030 640th St., Newell – 1 mile southwest of Newell and a quarter mile east. 

According to the latest NASS report, the 2019 corn crop is about 2-weeks behind normal in terms of reaching dent stage. What are the implications of this delay in grain filling period and end of season yield? We address this question by examining two key weather variables; solar radiation and temperature.

We've gone from being too wet to the other extreme of being dry in parts of the state. Below is a summary of the most recent US Drought Monitor (USDM) map for the state of Iowa and a brief explanation of what data goes into making the USDM.

Current Conditions in Iowa.

Now is the time to be doing late summer seeding of forages. This ICM article Steve Barnhart, retired Extension forage specialist, wrote does a nice job providing basic information to successfully establish a late summer seeding of forage. Read on for suggested times to complete a late summer seeding and for weather/environmental considerations when doing late summer seedings.

Limited rain fell across the state this past week, and approximately 36% of the state is considered to be abnormally dry according to the U.S. Drought Monitor as of last Tuesday, August 6. In addition to the dry conditions and moisture stress, other issues ISU Extension and Outreach field agronomists saw this past week included soybean gall midges, soybean aphids, the start of a third generation of thistle caterpillars, growth regulator injury in soybeans, and Tar Spot in corn.

The current approach to weed management in Iowa is at risk due to rapid expansion of herbicide-resistant weeds. In order to preserve the efficacy of herbicides two things must happen: 1) adoption of integrated weed management, and 2) shift the goal of weed management from protecting crop yields to minimizing the size of the weed seed bank. The first requires a shift in behavior, the second a change in attitude.

When will the first hard freeze or killing frost (equal to or less than 28°F) date be this fall? This is a question a lot of folks are wondering about right now. Over the last few decades the trend for the first frost and freeze dates in the fall has been that they are occurring later in the season when compared to the long-term behavior. The figures below illustrate the average first freeze (32°F) and frost (28°F) dates across the Midwest from 1980 to 2010.

The growing season started off too wet, but now we are going to the other extreme of being too dry in places. According to the U.S. Drought Monitor, just shy of 25% of the state was considered abnormally dry as of July 30.

Today in our corn efficacy evaluation trial, Ashley and our undergraduate team found small corn earworm caterpillars infesting ears (Figures 1 and 2). Caterpillars have a light-colored head but vary considerably in color from light green, tan, pink, maroon, and nearly black. However, they almost always have alternating dark and light lines running lengthwise down the thorax and abdomen and distinct tubercles (bumps) along the side of the body.

Growth regulator damage in soybeans, potato leaf hoppers, gray leaf spot, and thistle caterpillars have been some of the issues or pests ISU Extension and Outreach field agronomists have seen in fields this past week. Read on to see what is happening in specific areas across the state.  

Northwest Iowa

I was recently asked if adult corn rootworms are done emerging for 2019. Of course, I respond by saying – it depends! A publication by Nowatzki et al. (2002), developed an emergence model for northern and western corn rootworm in Iowa. It all starts with the biofix, which is just fancy way of saying “first catch.” After the biofix is reached, the duration of emergence is based on heat units, or accumulating degree days (ADD).

As July comes to a close, it is time to make plans to seed fall cover crops. Cover crop species, seeding method, seeding rate, and timing will all depend on the goals for that cover crop. In broad terms there are three methods: 1) overseeding, 2) drill seeding, and 3) broadcast seeding with incorporation. Each of these methods has pros and cons, which will be discussed in this article.

This past week brought some much needed rainfall to areas across the state, which helped the crops through the hot temperatures. The pest of the week across the state seems to be thistle caterpillars causing defoliation in soybeans, which are particularly bad in central and west-central Iowa. Read on to see what else ISU Extension and Outreach field agronomists are seeing and hearing about in fields across the state.

Northwest Iowa

Corn is starting to tassel and beans are flowering so no wonder everyone is asking about fungicides.

There is also a lot of talk about preventative and curative fungicides. Some fungicide labels also use these terms. What exactly do they mean? When is a fungicide “preventative”? When is it “curative”? What should you be applying to protect your crop from disease? Is one better than the other?

Check out what ISU Extension and Outreach field agronomists have been seeing and hearing about in fields across the state this past week. Some of the common issues observed in fields include insect defoliation in soybeans by pests like thistle caterpillars and Japanese beetles, weed management challenges, and crops starting to show signs of stress due to the heat and lack of moisture. Read on for more information about what’s happening in specific regions across the state.

A new article recently released through the Crop Protection Network (CPN) discusses how to make fungicide decisions in corn and soybean, given the delayed planting scenarios across the Midwest. The article takes into account yield potential at various planting times throughout the North Central region, as well as the previous wet and cool conditions when evaluating for a positive return on investment, in 2019.

Question: If the state and county are so concerned about wild parsnip, why aren’t they out spraying it? The ditches and county roads are full of it.¹

The annual ISU Extension & Outreach Iowa State Fair Weed Identification Contest will be held on Friday, August 9, from 9:00 – 11:30 a.m. in front of the John Deere Agriculture Building.  With three divisions , it is sure to be fun for the entire family!  Winners will be announced at the 3:00 p.m. Awards Ceremony inside the John Deere Agricultural Building.