Wallaces Farmer

A lot more corn will be tasseling next week in Iowa; scattered reports of soybean aphids.

June 29, 2016

4 Min Read

Each week, Iowa State University Extension and Outreach field agronomists report crop conditions in their area of the state. Here are the reports of what’s going on in fields around Iowa this week:


Northwest—Paul Kassel: Corn planted April 17 is at the V11 growth stage, and corn planted May 7 is about V9. Most of the crop looks good. There are some areas in northwest Clay County and northwest Dickinson County that are really wet. There are also areas of light soils in those same counties where the corn is rolling up on the light soil areas. Soybeans planted in April are V5/R1, and some soybeans have just been planted in the wet areas I mentioned above. Most farmers are completing their herbicide application on soybean fields. There are lots of fields where there is some leaf burn to the soybean crop because of the PPO/group 14 herbicide usage.

North Central—Angie Rieck-Hinz: In north central Iowa, corn is V10 to V13, and soybeans are V4/R1. I haven’t seen any leaf diseases or aphids, but there are scattered reports of soybean aphids at very low levels. The second cutting of hay crop started late the week of June 20.

It is clearly a tale of two stories in terms of rainfall across my nine counties. Eastern Wright and Franklin counties and north continue to receive rainfall usually in the amounts of 1 inch or more every few days; some places received 4 inches on Saturday night. Southern Hardin, Hamilton, Webster, and parts of Calhoun counties are dry and have not received significant rainfall for nearly four weeks. 

Northeast—Brian Lang: Counties in my area of northeast Iowa received some rainfall last week, and has had a total of 5-10 inches of rain over the past month, depending on the location. If the precipitation total at your farm from April 1–June 30 is close to 16 inches or more, consider an additional nitrogen (N) application. This assumes that N applied so far was not more than the maximum return to N (MRTN) rate. MRTN rates can be determined with the Corn N Rate Calculator.

General rainfall accumulations for northeast Iowa for that timeline are around 11-13 inches, but some localized areas may be higher. Click here for a rainfall graphic from April 1 to June 24. Unfortunately, the precipitation totals are not reliable enough to indicate how much additional N may be needed. Read more about nitrogen application in this article: Precipitation and nitrogen this spring.

Central—Mark Johnson: Most areas of the nine counties I serve in central Iowa have been dry. Rain over the weekend amounted to about 0.3- 1.4 inches of rain. Even now, much of the area shows up on the Drought Monitor map.

Corn is close to tasseling in much of the area with some ready to tassel this week; a lot more will early next week. Lots of soybean fields are at least V6 and many are R1. I did not receive any calls about insects or diseases in the last week. 

ISU agronomists report “what’s up” with crops this week

South Central, Southeast, East Central

* Rebecca Vittetoe: This past week parts of my area received some much needed rain (ranging from a few tenths to almost 2 inches in locations), but there are some areas that didn’t get much, if anything, and could really use some rain. According to the U.S. Drought Monitor, most of my counties are now classified as in a “moderate drought.”

Crops are moving right along. Folks have started making second cuttings with alfalfa, some soybean fields have started to flower (R1), and corn should be tasseling soon. Weeds have also been moving right along. I’ve had a few calls about why aren’t my weeds dying after my herbicide application? A lot of it seems to stem back to WEED SIZE! If the label says it controls weed-x between 4 to 6 inches, thinking that same herbicide is going to control weed-x when it is 12 to 18 inches tall is not realistic at all. I haven’t seen much insect or disease activity. Map of last week's precipitation totals.

* Virgil Schmitt: We had anywhere from zero precipitation (parts of Lee County) to over 5 inches of rain in southern Muscatine and northwestern Louisa counties, and generally over 2 inches north of I-80. There was also wind and hail, resulting in at least four irrigation rigs being toppled, the vegetable crop being destroyed, corn leaves stripped, and soybeans denuded in Fruitland, Iowa. Corn is V13-V15, and soybeans are mostly V1. Hay is looking good, and I know of some second cutting that has been made. Drift, herbicide resistance, and surfactant injury were the common calls. Japanese beetles are also a topic of conversation.

Find your local ISU Extension and Outreach field agronomist here!

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