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Regional Crop Update June 11 to June 19 2018

Tue, 06/19/2018 - 12:07

Parts of Iowa received some much needed rainfall last week, but unfortunately for some areas the storms that rolled through also brought along hail and caused flooding. Overall, crops are looking good across the state with 84% of the Iowa corn crop and 80% of the soybeans crop being rated in the good to excellent condition based on Monday’s USDA Crop Progress Report. Iowa State University Extension and Outreach field agronomists report crop conditions in their respected regions.  

Northwest Iowa

Joel DeJong (Region 1): “The NW Corner of Iowa had a mixed week – some areas received almost no rainfall, and areas of O’Brien and Osceola County had many reports over 6” of rain. Localized flooding occurred due to that rainfall event. Areas that did not receive rain last week have already had a good rain early this week. For the most part, crops are looking very good, and the U2U growing degree model shows predicted silking for many fields before the middle of July – and some in early July. Soybeans at the NW Research have begun to bloom in the 4/30 and 5/7 planting date plots. There remain some yellow streaks in a few cornfields, some carry-over herbicide issues, and a few cases of herbicide drift. Watch weather conditions and understand the label before all herbicide applications!”

Soybeans planted on 4/30 and 5/7 are blooming at the NW IA Research Farm. Photo by Joel DeJong. 

Paul Kassel (Region 2): “Field work progress has come to an abrupt halt for much of my area. Recent rains have been excessive in parts of Pocahontas, Clay, Palo Alto, Dickinson and Emmet Counties. In contrast, there are areas in Sac and Buena Vista Counties that are dry – and have received only a couple of inches of rain in June. There are some corn fields that will not get their postemergence herbicide application – due to the recent windy weather, rainy weather, excessive rain, etc. There is also concern of the timeliness of the postemergence herbicide for the soybean crop. The pre-emergence products are working quite well.  However, it may be a challenge to be timely with fomesafen (10-month corn rotation restriction) and dicamba (weed size and potential for off target movement).”

Corn crop showing injury from a 2017 misapplication of fomesafen in Pocahontas County. Note that even the replanted corn is also showing injury symptoms. Photo by Paul Kassel. 

Northeast Iowa

Terry Basol (Region 4): “Corn and soybeans continue to develop rapidly in NE Iowa, given the warm temperatures and current soil moisture conditions for the past week. Corn is anywhere from V5 up to V8 – V9 and we are still seeing some fields that are showing signs of rapid-growth syndrome (pictured above). For more information on rapid growth syndrome, see the ICM article titled: Twisted whorls, buggy whipping, yellow leaves. In general, soybeans are anywhere from V3 up to R1 for most of NE Iowa, with postemerge herbicide applications occurring throughout the area within the last week. Oats in NE Iowa are 46 percent headed out according to the most recent Iowa Crop Progress & Condition report by the National Agricultural Statistics Service (NASS). Eighty-three percent of the oat crop statewide was rated in good to excellent condition.”

Corn field with plants showing symptoms of rapid growth syndrome in NE Iowa. Photo by Terry Basol. 

North Central Iowa

Angie Rieck-Hinz (Region 3): “The week of June 11 saw spotty to heavy rain across central to NC Iowa. Rainfall reports indicated amounts of 0.5 to 6 plus inches. While some areas received too much rain, the eastern most part of Story County, parts of Hardin and Marshall could use some rain. In areas with excessive rain, we have a lot of ponding and loss of crop in potholes and other places where the rain was so intense we experienced severe erosion washing out areas in fields. There are still areas in the northern regions that were planting soybeans last week. I have received several phone calls on herbicide carryover from 2017 as well as herbicide injury from tank contamination. On Friday (June 15) I looked at an armyworm infestation in a soybean field that had a cereal rye cover crop. The armyworms were not eating the soybeans, but were defoliating the bromegrass in the ditch and moving into the corn. This should be a reminder to anyone who had a cereal rye cover crop to scout for armyworms, not only in the soybean field but also adjacent corn fields. Armyworm will eat soybean, but prefer grass.” 

Southwest and West Central Iowa

Aaron Saeugling (Region 9):  “Corn is looking good as isolated showers have helped keep the corn growing. Herbicide applications and sidedressing nitrogen has basically wrapped up in corn. Currently, not seeing any major insect issues as of right now. Unfortunately, some areas experienced hail damage, but most of the corn is growing out of the damage. Heat and lack of rainfall will be the challenge in the coming weeks. While the corn is looking good, the soybeans have struggled a little bit more. We have had several issues this spring with soybean emergence due to herbicide issues, planting depth, diseases, and insect pressure. The focus this week in soybeans will be post emerge herbicide applications. My recommendation for farmers is to scout, scout and scout. Hay and pasture conditions are holding on right now. If you feel pasture may be short in the coming month either rotate pastures or supplement cows now to avoid overgrazing. A little supplement now will pay big dividends this fall for grazing and regrowth of pastures.”

Southeast and East Central Iowa:

Rebecca Vittetoe (Region 10) and Josh Michel (Region 11): “We received some much needed rainfall in parts of SC Iowa, which really helped the crops through the heat this past weekend. Rainfall ranged from three or four tenths to a couple of inches in areas. Corn is mostly in the V10 to V12 stages and soybeans are mostly V3 to V5 stages, with many fields already flowering (R1). Common issues, calls, and field visits last week included yellow and uneven corn, potassium deficiency showing up in corn, herbicide issues, and weed control challenges. It was not uncommon, especially on the really warm days, to see corn leaves rolling. Potato leaf hoppers were found at the ISU McNay Farm near Chariton in the alfalfa plots, so that is a good reminder to get out and scout for potato leaf hoppers. Another insect pest to keep an eye out for is Japanese Beetles as they have started to emerge. Just be careful not to be them confused with chafers, another beetle that at first glance is often mistaken for Japanese Beetles. Pastures and hay fields are hanging in there, but pond levels are really showing how dry we are in SC Iowa.”  

(Left photo)Take the time to scout your alfalfa fields for Potato Leafhoppers. (Right photo) Corn plants in a field just south of Centerville, IA on 6/15/18 showing signs of potassium deficiency and leaf rolling due to the dry conditions in this part of the state. Photos by: Rebecca Vittetoe. 

Virgil Schmitt (Region 8): “During the last week, in the counties I cover, areas roughly east of HWY I-380, HWY 281, and HWY 27 received less than 0.5 inch of rain while areas roughly west of that line received between 0.5 and 1.0 inch of rain. Oats are heading out. Corn is mostly V10 plus or minus one leaf, and it is generally in good condition. However, the corn has been showing signs of moisture stress during the hottest portions of the day. Soybeans are mostly V3 plus or minus a leaf. A few fields are at R1 and there are even some fields at R2. Soybean fields generally look good. Calls started last week on herbicide group 4 injury symptoms on soybeans as well as calls regarding waterhemp management.”

Rainfall totals across the state of Iowa for the past 7 days. Source: http://www.weather.gov.

Find your local ISU Extension and Outreach field agronomist here!

Category: Crop ProductionTags: field agronomistscrop updatefloodinghaildry conditionsAuthor: Rebecca Vittetoe

Integrated Pest Management program now available on Facebook

Mon, 06/18/2018 - 15:27

The Iowa State University Integrated Pest Management (IPM) program is expanding its social media footprint to now include Facebook. If you follow our content on Twitter (@ISU_IPM) then be sure to give our page a like to stay connected.

Through Facebook, the IPM program hopes to reach a wider audience wherever they might source their information, to promote responsible land stewardship while promoting stable and high yields for farmers, as well as the responsible in-home management of household pests and plant diseases. We'll work to share and promote the information done by our partners, collaborators and researchers on Facebook in the form of articles, videos, surveys and community groups to continue the discussion of integrated pest management.

To quickly find our account, go to facebook.com/ISUIPM, and click on the "like" button.

Be sure to check back in for more updates coming to the IPM program!

Category: Insects and MitesPesticide EducationPlant DiseasesTags: integrated pest managementcrop scoutingInsectsdiseasesAuthor: Ethan Stoetzer

Flooding and Hail, Oh My!

Fri, 06/15/2018 - 08:03

Yesterday’s heavy rains that marched across large part of central and north central Iowa coupled with recent storm systems across other parts of the state have resulted in significant areas of ponding as well as hail injury.

Flooded fields will take several days for the water to recede to fully evaluate how much crop areas was destroyed. A may be able to survive under water for 1 to 4 days depending on the crop stage and air temperature. And even if the crop does survive, saturated soil conditions will undoubtedly stall root growth and hinder nutrient uptake and growth. At this stage of the growing season, it is unlikely that replanting drowned out areas will be a viable option. However, when the water recedes and field conditions are fit, it would be worthwhile to plant a cover crop to protect the soil and compete against weed growth. ICM News Corn Survival in Flooded or Saturated Fields has some additional information on survival of corn that has been under water.

Hail injury to the corn and soybean crop will be relatively minor in the earlier growth stages. Yield loss from hail to corn increases through vegetative growth and peaks at pollination before decreasing through grain fill. Whereas, soybean hail injury increases as the growing season progresses and peaks during the seed filling stages. At this time of the year, hail injury may only result in a 5-20% corn yield loss or 5-30% soybean yield loss. ISU Extension publications Hail on Corn and Hail on Soybean have additional information on management options and yield impacts from hail injury.

Flooded and hail injured demonstration plots at the Field Extension Education Laboratory on June 14, 2018.

Category: Crop ProductionTags: floodinghailcorn managementsoybean managementAuthor: Mark LichtCrop(s): CornSoybean

Don’t mistake this look-alike chafer

Thu, 06/14/2018 - 15:46


This week, I’ve had a number of people tell me they spotted Japanese beetle. I was initially surprised, because I track degree days to predict adult emergence every summer and it seemed a bit early. According to the ISU Agronomy Mesonet, adults could be emerging in southern Iowa and I would expect adult emergence in central Iowa next week. See my recent ICM News article showing a degree-day map for 2018.

Last night, I attended a field demonstration highlighting herbicide resistance near McCallsburg, IA. I was constantly bombarded with beetles and flies. I finally got a good picture of one of the beetles and noticed it was the false Japanese beetle (Photo 1). Obviously, there is some confusion out there (even by a trained entomologist!), so I thought I could post a few pictures to help you confirm the identification. It is important to distinguish Japanese beetles (Photo 2) from other chafers because other species are not known field crop pests. The false JB is not a concern in corn and soybean.

They do resemble each other in the size and shape, and are in the same subfamilies of beetles called shiny leaf chafers (Rutelinae). True Japanese beetles are more iridescent with a metallic green head and thorax with copper-colored forewings. The false Japanese beetle is not quite as shiny (sorry, that is up for your interpretation!). Also, the white tufts of “hair” along the sides and tip of the abdomen are not as obvious.


Photo 1. False Japanese beetle. Photo by Erin Hodgson.

Photo 2. Japanese beetle. Photo by David Cappaert, www.ipmimages.org.


Category: Insects and MitesTags: beetlescoutingdefoliationpestAuthor: Erin HodgsonCrop(s): CornSoybean

Regional Update: Crop Progress and Update for June 5 to June 13 2018

Wed, 06/13/2018 - 11:45

While parts of Iowa are too wet and have experienced hail, wind, and flooding over the past week other parts of the state could desperately benefit from some rainfall. Despite the drastic differences in moisture levels across the state, according to Monday’s USDA Crop Progress Report, approximately 81% of Iowa’s corn crop was rated in the good to excellent condition and 78% of the soybean crop was rated in the good to excellent condition. Iowa State University Extension and Outreach field agronomists report planting progress and crop conditions in their respected regions.  

Northwest Iowa

Joel DeJong (Region 1): “The NW corner of Iowa did not receive excessive amounts of rain in the last week, but most of the area received at least some rainfall. It's been several years since I remember knee high corn on the fourth of June, but we had several of the early planted fields that tall this year. Even the late planted cornfields look to be off and growing now. We are starting to see cornfields with scattered white leaves coming out of the whorl. This is due to what's called rapid growth syndrome. The corn is growing so rapidly it gets tied up in the whorl for a short time before it suddenly unwraps and exposes those lighter colored leaves. They will return to normal color shortly. I've been in several fields in the past week with some stress from herbicide carry-over after the dry summer last year and a few with herbicide drift damage. I've even seen one with dicamba drift onto a soybean field. A good reminder to know what your neighbor has in their field, and apply safely!”

Paul Kassel (Region 2): “Field work progress has caught up across much of my area – for the most part. There were still some soybeans being planting last week in the wet areas of Kossuth and Palo Alto counties. There is some tremendous looking corn and soybean crops in all of my area.  A recent trip to Sac County showed some corn at V8 stage and soybeans at the V3 growth stage. In general, the corn that was planted around May 25 is now at the V4 growth stage.  While parts of my area of been wet, there are parts of my area – in Sac and Buena Vista counties for example – that are on the dry side and could use a rain.”

Soybeans emerge from a fall seeded rye cover crop in Clay county recently treated with glyphosate and Engenia. Photo by Paul Kassel. 

Southeast and East Central Iowa:

Rebecca Vittetoe (Region 10) and Josh Michel (Region 11): “This year unfortunately seems to be a repeat of what we experienced last year as far as rainfall goes in this part of the state - limited and very spotty. Most of SC Iowa has received approximately 50% or less of normal rainfall over the last 30 days. Although the corn and soybean crops are looking good despite the dry conditions, if these conditions continue things will start looking a lot different. On average, corn is around the V8 to V9 growth stage and soybeans average around the V5 growth stage. There are some soybean fields that are already flowering (R1). Pay close attention to crop growth stages, especially when making herbicide applications. Common questions over the past week included herbicide injury and herbicide carryover in corn and soybeans, yellow and uneven corn, and sulfur and potassium deficiency symptoms appearing on plants. In most of these cases the nutrient deficiencies aren’t true deficiencies, but they are related to environmental conditions and crop growth stages. Pastures and hay fields are looking pretty good, but could really benefit from some rainfall. With the first cutting of hay basically done, now is a good time to be scouting and keeping an eye out for potato leaf hoppers.”

Meaghan Anderson (Region 7): “Corn and soybeans are both taking off in east central Iowa, with corn anywhere from V7 to V12 or V13 and soybeans anywhere from VC to V4 or V5. Some of the earliest planted soybeans may even be starting to flower already. Several much needed rains brought moisture to east central IA last week but also brought unwelcome hail and wind with it in some cases. In particular, Tama County had fairly large hail last Wednesday night and early Thursday morning; now is a good time to evaluate those crops for recovery after that storm. ISU has great hail resources for corn and soybean for those who need them. Corn POST herbicide applications are mostly wrapped up and soybean POSTs are getting underway. Timely application to small weeds is key to getting good control, particularly of waterhemp. Recent phone calls have been continuing about yellow corn - compaction, dry soils, herbicide carryover, and flashing of sulfur deficiency continue to be the leading causes. Soybean calls are just beginning with three reports of plant growth regulator herbicide drift into soybeans and other phone calls on leaf feeding or herbicide carryover.”

Virgil Schmitt (Region 8): “During the last week we received very little rain in the southern counties while parts of Clinton and Jackson Counties received over six inches. Hay harvest is mostly complete. Corn is mostly in the V8 +/- 1 one leaf for growth stage. Rooting issues resulting in sulfur and potassium deficiency symptoms dominated calls last week. Herbicide injury is also present in some fields. Soybeans are mostly V2 +/1 one leaf and generally look good.”

Rainfall totals across the state of Iowa for the past 7 days have been spotty ranging from a few tenths to inches in some places. Source: http://www.weather.gov.

Find your local ISU Extension and Outreach field agronomist here!

Category: Crop ProductionTags: field agronomistscrop updateAuthor: Rebecca VittetoeCrop(s): Soybean

Southeast Research Farm Spring Field Day and CCA Training Set for June 28

Tue, 06/12/2018 - 08:12

On June 28, Iowa State University Extension and Outreach will be hosting the annual Spring Field Day and Certified Crop Advisor (CCA) Training at the Southeast Iowa Research and Demonstration Farm near Crawfordsville.

The morning will feature a CCA training session, which will begin at 9 a.m. The morning CCA training session will feature the topic of soil health concepts and measurements by Marshall McDaniel, Associate Professor of Agronomy at ISU. McDaniel will provide an overview of what soil health is, measuring soil health, and associated challenges. There will be a field component to the morning session demonstrating different ways to measure soil health. CCA's can 4.5 hours of continuing education credits by attending the morning session and the afternoon field day. 

The field day, which is free and open to the public, will begin at 1 p.m. Topics that will be covered during the field day include: “Crop Season Review” by Myron Rees, farm superintendent; “Practical Ways to Measure Soil Health” by McDaniel, “Dicamba Management in 2018” by Bob Hartzler, ISU Extension Weed Scientist; “Planting Corn into Cereal Rye: Termination Timing and Planting Demo” by Alison Robertson, ISU Extension Plant Pathologist.

Pre-registration for the CCA morning session is required and can be completed by completing the online registration form. Check-in begins at 8:30 a.m. on the day of the event. The registration fee of $50, which includes lunch, can be paid with cash or check at the door. If you cannot register online, call ISU Extension Johnson County office at 319-337-2145, or contact Meaghan Anderson at mjanders@iastate.edu. Please register by June 22 for the morning CCA session. There is no cost or pre-registration for field day in the afternoon. 

We hope you can join us for the CCA training and the field day! 

More information about these events can be found on the event flyers: CCA Training Flyer  and Spring Field Day Flyer

The Southeast Research and Demonstration Farm is located at 3115 Louisa-Washington Road, Crawfordsville. To reach the research farm go 1 3/4 miles south of Crawfordsville on Highway 218, then 2 miles east on G-62, then 3/4 mile north.

Category: Crop ProductionTags: dicambasoil healthCorn diseasescover cropsfield dayAuthors: Meaghan AndersonVirgil SchmittJoshua MichelRebecca Vittetoe

FACTS releases first 2018 yield forecast

Fri, 06/08/2018 - 16:14

The 2018 growing season is well underway. It is now time to start assessing the rewards of the spring planting season. Our first FACTS (Forecasting and Assessment of Cropping sysTemS) is now live for the 2018 growing season. There have been a couple of changes going into our fourth year. A field site at the ISU Northern and McNay Research and Demonstration farms have been added to increase geographic coverage. For each site only the ‘normal’ or treatment nearest ‘normal’ is included on the webpage to reduce complexity. Yield forecasts have been moved to the opening page of the Forecast Tool and relative yield values have been removed. We hope these changes make for a more meaningful user experience.

Highlights of the June 4 forecast

Soil nitrate-nitrogen is adequate to meet the increasing crop nitrogen requirement as corn rapidly increases both biomass and nitrogen uptake. Compared to 2016 and 2017, central Iowa corn planted on May 8 is 1.5 leaf stages further along resulting in 40% LAI (leaf area index) and 25% deeper rooting depth as of June 8; largely a result of greater accumulation of growing degree units from May 1 to June 8. In northern, because of later planting dates, there was less leaf development, LAI, and rooting depth gained. Whereas in southern Iowa where planting dates were slightly earlier, corn leaf development and LAI were slightly higher. Soybean growth and rooting depth generally followed the same results as corn with more leaf area and deeper roots in southern Iowa followed by central Iowa followed by northern Iowa.

Our analysis shows that the corn and soybean crop generally have a high yield potential even with the near record warm May experienced across the state. Across the state there is some variability in corn yields (approximately 265-205 bu/ac) compared to soybean yields (70-65 bu/ac). The forecast indicates that the highest soybean yields will occur from southwest to central (Kelley) Iowa while the lowest corn yields will be in south central and southeast Iowa.

Look for a new forecast in 7 to 10 days.

Category: Crop ProductionTags: FACTScorn yield forecastAuthors: Sotirios ArchontoulisMark LichtCrop(s): CornSoybean

Would a fungicide benefit hail-damaged crops?

Fri, 06/08/2018 - 09:41

Widespread hail occurred in Iowa on 6 June 2018, causing damage to many acres of corn and soybean plants. At this time, most of the corn is in the V6 to V8 growth stages, while soybeans are at the V1 to V3 growth stages. Some areas of the state also received hail injury earlier this season. Questions have been raised regarding the benefit of a fungicide application to hail-damaged crops in these early to mid vegetative stages.

Tattered leaf tissue and broken leaf midribs on vegetative stage corn resulting from hail. Photo by Mark Licht.

There are a few reasons given for fungicide application to crops after a hail event. It is argued that crops may be more susceptible to fungal pathogens resulting from increased stress due to the hail injury, or that wounding may allow pathogens to invade plant tissue. Another reason fungicides are considered post hail is that physiological benefits gained from a fungicide application are thought to help sustain or increase yield of damaged crops. It is important to note that claims by the chemical industry do not state fungicide applications recover yield potential lost due to hail damage. But some claims do suggest fungicide application to hail-damaged crops will protect the remaining green tissue and allow plants to maximize yield after sustaining damage.

Tattered and missing leaves on vegetative stage soybean resulting from hail. Photo by Mark Licht. 

In order to help answer the question of whether or not fungicide application after a hail event during vegetative crop stages is beneficial, field research trials were undertaken by Iowa State University researchers. During 2015 and 2016, trials at research farms in Kanawha, Iowa, and Ames, Iowa were performed using a hail simulation machine and subsequent fungicide application. 

In corn, hail was simulated at approximately V5 and V9 and fungicide (pyraclostrobin + metconazole) was applied 1 to 2 weeks later as a “post hail response” or at R1. A treatment that had both the post hail response fungicide and R1 fungicide application was included.

In soybean, hail was simulated at approximately V5, and fungicide (fluxapyroxad + pyraclostrobin) was applied approximately 7-10 days later as a post hail response and also at R3. A treatment including both the post hail response and R3 application was included as well. 

Although analysis is ongoing, a preliminary examination of results may indicate the following:

Corn. As expected, plots with hail injury yielded less than non-injured plots. However, fungicide application as a post hail response or at any other timing did not provide significant (P=0.1) yield-increasing plant health benefits for corn after V5 and V9 hail when compared to plots that did not receive fungicide. 

Soybean. As expected, soybean plots with hail injury yielded less than non-injured plots. The soybean yield data is a bit more complex than the corn, but what it does tell us is that a single, post hail response fungicide application does not statistically (P=0.1) increase yield after V5 hail when compared to plots that did not receive fungicide. 

These data are similar to those we previously reported for fungicide applications after a hail event during early grain fill. In general, a fungicide application may not provide yield-increasing benefits after an early-season hail event when risk of foliar diseases is low. Furthermore, it is important to consider how low grain prices increase the number of bushels needed to recover the cost of fungicide application. 

If you do plan on making a fungicide application after early-season hail, it may be advantageous to leave an untreated strip in the field to determine if the application was beneficial come harvest – not only in terms of yield, but also economically. 

The following resources are available from ISU Extension and Outreach Publications as free downloads:  

Hail on Corn in Iowa (IPM 0078) at https://store.extension.iastate.edu/product/14776 

Hail on Soybean in Iowa (IPM 0079) at https://store.extension.iastate.edu/product/14792 

Category: Crop ProductionPlant DiseasesTags: hailfungicidespraysprayingapplicationhail damagewoundingCornSoybeanAuthors: Adam SissonDaren MuellerAlison RobertsonCrop(s): CornSoybean

Twisted whorls, bugged whipping, yellow leafs

Wed, 06/06/2018 - 10:01

Over the last week there have been sightings of twisted whorls and buggy whipping or corn leaves. It’s also known as rapid growth syndrome, accelerated growth syndrome, roping, wrapped whorls, and onion leafing, This is not unusual for corn that is growing rapidly and usually occurs in 5th to 7th leaf corn but can also occur as late as 12th leaf corn. Most of the time this occurrence is due to rapid growth as plants benefit from warm temperatures, rainfall after being dry, or development of nodal roots. Some genetics have a greater propensity for occurrence than others do. Growth regulator and acetamide herbicides can also be the culprit.

Typically these the wrapped whorls will unfurl in 3 to 7 days. The outer leaves will have a rippled appearance and the inner leaves will be yellow to white in appearance. As photosynthesis ramps up those yellow leaves will green up rapidly. The affected plants will have minimal, if any, impact on grain yield. The take home message is be patient and let nature take its course.

Category: Crop ProductionTags: Corncorn productioncorn growthtwisted whorlsAuthor: Mark LichtCrop(s): Corn

Regional Update: Crop progress for May 29 to June 5, 2018

Tue, 06/05/2018 - 21:03

Despite the late start to #Plant18, especially in northern Iowa, planting has nearly wrapped up with corn and soybeans across the state. According to Monday’s USDA Crop Progress Report, approximately 91% of Iowa’s corn crop has emerged with 81% of the corn being rated in the good to excellent condition. On the soybean side, approximately 72% of the soybean crop has emerged with 80% being rated good to excellent and 20% being rated poor to fair. Although it seemed like we had a slow start to the growing season with April being one of the coldest on record, May ended up being the opposite as one of the warmest May's on record. In fact, growing degree days (GDDs) are actually ahead of normal across the state. Iowa State University Extension and Outreach field agronomists share crop conditions and what they are seeing in their respected regions across the state.  

Despite the slow start to the 2018 growing season, growing degree days are ahead of normal across the state. Source: ISU Meosnet

Northwest Iowa

Paul Kassel (Region 2):  “Field work progress has been a struggle this spring – but planting is nearing completion. The Memorial Day weekend and the last few days of May saw a lot of the soybean planting completed. There are still a few wet areas that are behind with field work progress. Those areas include an area in north central Emmet County, parts of southern Kossuth County and eastern Palo Alto County. These areas saw some heavy rains on May 23 that caused some ponding and drowned out areas. There will be some replanted corn in those areas. Corn development has been fast with the recent warm temperatures. Corn planted on April 29 is at the V6 growth stage. Growing Degree Day (GDD) accumulation is about 105 units above normal for the April 29 planting date and about 90 units above normal for the May 25 planting date. These additional GDDs represent about an extra week’s time in terms of crop development.”

A Clay County farmer finishes no-till planting on June 4. Photo by Paul Kassel. 

Corn planted on May 22 in Clay County now at the V2 growth stage. Photo by Paul Kassel. 

Northeast Iowa

Terry Basol (Region 4): “Growers in NE Iowa have been able to complete corn planting within the last couple of weeks, which has been really nice to see. Corn development ranges in my territory from VE to V2 in the northern area up to V6 in the southern area where planting operations occurred first.  Soybean planting progress has been going well throughout the territory, and ranges from just planted up V2 or V3.  According to the most recent Iowa Crop Progress & Condition report by the National Agricultural Statistics Service (NASS), 88% of the soybean acres in NE Iowa have been planted. Both corn and soybeans look very good in the area as long as we can continue timely rain events throughout the growing season. First cutting of alfalfa and hay has begun in the area, and it is estimated to about 35% completed according to NASS.”

Southwest and West Central Iowa

Aaron Saeugling (Region 9):  “Corn is doing well after the recent rain. We continue to be on the dry side with rain needed weekly. Compared to 2017 we have less available soil moisture. Corn ranges from V6 to V10. We have seen various issues from sulfur deficiency, wireworms, cutworms, herbicide interactions, and wet planting issues. Soybeans are all planted and emerged.  Most soybean are V1 to V3 growth stage. Most farmers will be focusing on spraying the next few weeks. There have been a few reports of bean leaf beetle feeding. Overall though, the corn and soybeans are looking pretty good. First cutting hay is baled or will be finished shortly. The hot weather made for some difficulty baling due to shatter loss when baling. Cover crops for forage are harvested or are in the process overall tonnage looks pretty good considering the cold April.  I’ve seen a few herbicide carryover issues causing poor growth and forage yields. Pasture conditions were saved by this last rainfall.  We are going to be on the edge all summer for those areas where pasture was short and not allowed to rest this spring. Farmers in those areas need to consider nitrogen if rainfall is expected after application.  If at all possible consider summer annuals for supplemental forage.”

Southeast and East Central Iowa:

Rebecca Vittetoe and Josh Michel (Region 10 and 11): “Rainfall continues to be spotty across SC Iowa. With not replenishing soil moisture from last year, weekly rain is definitely needed as the area is either abnormally dry or in a moderate drought according to the U.S. Drought Monitor. Overall though corn and soybeans look good. Most corn is in the V6 to V8 growth stages, and soybeans range mostly range in the V1 to V3 growth stages. Most phone calls over the past week have consisted of herbicide carryover (ALS, PPO, and HPPD), stunted and uneven corn, and sulfur deficiency in corn. Post spraying and sidedressing has basically wrapped up in corn and there is a lot of post spraying occurring with soybeans right now. On the forage side, first cutting hay is basically complete. Pasture are looking okay, but consistent rainfalls will be needed to help them going. Pond levels are really low.”

Sulfur deficiency will appear as intervenial chlorosis (left photo) while fomesafen carryover will appear as venial chlorosis (right photo). Photos by Rebecca Vittetoe. 

Meaghan Anderson (Region 7): “Most corn is just getting out of the ‘ugly duckling’ stage and reaching V6 to V7 stage, but some corn is still yellowed and uneven. Most phone calls have been on stunted corn due to compaction, variable soils, variation in how quickly corn plants reach nitrogen, or herbicide carryover (ALS and PPO). Soybeans are mostly in the V1 to V3 stage, and most look very healthy with good stands this year. GDDs are far ahead of normal in many areas, so continued rainfalls will be important to keep up with the continued heat. Spraying has mostly finished up in corn and is just starting in earnest for soybeans, but weeds seem well-controlled overall so far this spring.”

Corn plant stunted from ALS carryover (left photo). Compaction affecting normal corn root growth and development (right photo). Photos by Meaghan Anderson. 

Virgil Schmitt (Region 8): “Rainfall has been scattered during the last two weeks, ranging from a trace to nearly two inches. First harvest of hay is nearly complete. Many completed harvest with no rain on down hay while others had hay that was rained on several times. Corn is mostly V6 to V7 and generally looking good. Flexstar (fomesafen) carryover and S deficiency symptoms have dominated calls. Soybeans are mostly V1 and generally looking good. There are some emergence issues is some areas where there was pounding rain. There was a band of hail in northeast Cedar and Southwest Clinton County. There was little significant damage.”

Rainfall totals across the state of Iowa for the past 7 days have been spotty ranging from a few tenths to a couple of inches in places. Source: National Weather. Source: http://www.weather.gov.

Find your local ISU Extension and Outreach field agronomist here!

Category: Crop ProductionTags: field agronomistscrop updateAuthor: Rebecca Vittetoe

Iowa State University Integrated Pest Management Program Announces New YouTube Channel

Tue, 05/29/2018 - 14:54

The Iowa State University Integrated Pest Management (IPM) program is proud to announce the creation of its own YouTube Channel through which to promote the efforts of Iowa State University scientists and researchers in providing means-tested crop and pest management solutions to stakeholders in the state of Iowa and beyond.

At the “Integrated Pest Management Iowa State University” channel, viewers will find content detailing the efforts and reaches of the IPM program, best practices and information, as well as demonstrations on how to properly identify and evaluate various  insect and disease pests, and their impacts on field crops.

“With the creation of a specified channel for Iowa State University IPM, the IPM program will be able to diversify the information and content we create to make it more adaptive, more understandable and more effective in promoting our message,” said IPM Director Daren Mueller, professor of plant pathology and microbiology. “The use of video will further our mission to inform farmers, gardeners and agribusiness professionals of the best crop and pest management techniques, to not only create optimal yields, but to prevent pest resistance and other adverse consequences of chemical misuse.”



In addition, the new channel will feature videos from the Extension and Outreach Plant and Insect Diagnostic Clinic (PIDC) about identifying horticultural diseases and pests in homes and gardens, as well as showcase “How To…” videos about sampling and pest prevention.

The channel will also feature custom playlists of video content created outside of the Iowa State University IPM program, as a way to communicate the efforts and research of various departments across several universities in the region to promote the overall mission of Integrated Pest Management: helping stakeholders effectively and safely manage pests.

The IPM program will use the YouTube channel as one of several ways to promote means-tested practices for crop and pest management. Please click the subscribe link on our channel to make sure that you never miss a video the program creates. To get involved on the most up-to-date activities regarding IPM, follow the program on Twitter @IPM_ISU.

Category: Insects and MitesPesticide EducationPlant DiseasesTags: IPMYouTubevideoAuthor: Ethan Stoetzer

Learning to fly

Tue, 05/29/2018 - 08:17

Tom Petty said he was “learning to fly, but I ain’t got wings.” The last two weeks have made me think about flies way too much. The black flies, sometimes called buffalo gnats, have been terrible and making it hard to be outside. These small flies (1/4" in length) are black or gray and somewhat resemble a small house fly. The thorax is shiny and convex, giving them a humpbacked appearance. The adult females have scissor-like mouthparts and inflict a painful bite to access blood. The bites can cause itching, swelling, and red welts. Some people experience allergic reactions to the bites; however, they are not known to vector diseases to humans.

Buffalo gnat. Photo by Darren Blackford, www.ipmimages.org.

Black flies typically appear in late spring/early summer. Males and females feed on plant nectar and females also need blood for egg development. They like to feed on birds and mammals, including humans. Sometimes the fly swarms are so intense they can kill livestock and poultry.

Unfortunately, these flies are highly mobile, very aggressive and difficult to repel. There is limited success with DEET-containing sprays that are normally effective against mosquitos. Wearing long pants and shirts can help while outside. For the next couple weeks, we might have to “learn to fly” indoors as much as possible.

Category: Insects and MitesTags: flynuisancepestinsectAuthor: Erin Hodgson

Regional Update: Planting progress and crop conditions for May 14 through May 22

Tue, 05/22/2018 - 10:05

While #Plant18 has basically wrapped up in the southern part of the state for corn and soybeans are about three-fourths planted, #Plant18 has been much slower in the northern part of the state. According to Monday’s USDA Crop Progress Report, approximately 86% of Iowa’s expected corn crop has been planted and 53% has emerged, and on the soybean side, 58% of the expected crop is planted and 18% is emerged. Iowa State University Extension and Outreach field agronomists report planting progress and crop conditions in their respected regions across the state.  

Northwest Iowa

Joel DeJong (Region 1): “Planting progress in the NW corner of Iowa has gone well lately for most, with those south of about Hwy 18 mostly done with corn, and beans maybe two-thirds planted. The area of most concern, Osceola County, had field work progress in many fields starting late last Thursday, and proceeding over the weekend. About two-thirds of their corn looks to be in the ground now, and many remaining fields are still quite wet. Planting around wet spots is common. Not many beans are planted in that area. Counties near that have been slower to get the crop planted due to wet conditions, also. Counties to the south have a lot of corn emerged now, from spike to V2. Stands look good in those fields. Two Plymouth County alfalfa fields averaged 24” tall on Sunday, and not quite in the bud stage. The PEAQ relative feed value of this crop as it stands is 190. It will reach the bud stage soon.”

Paul Kassel (Region 2):  “We had a good stretch for field work last Thursday to Sunday – May 17 to 20.  Then things pretty much came to a halt with some widespread rainfall Sunday night. Corn planting progress is about 95% south of Hwy 3 and is about 75% between Hwy 3 and Hwy 18. Corn planting progress is about 50-60% along the Hwy 9 corridor. Soybean planting progress is about 25 to 50% - with the northern areas lagging the southern part of my area. The corn that was planted on April 29-30 or on May 7 has emerged. Some of this corn has struggled a little – with some farmers considering replanting on parts of these fields. Some farmers actually planted some of their soybean crop before corn. The 2017 corn fields that were fall tilled often dried faster than the unworked 2017 soybean stubble fields."

A custom applicator applying liquid nitrogen and herbicide to a field in Clay County. Photo by Paul Kassel. 

North Central Iowa

Angie Rieck-Hinz (Region 3): "A very small percentage of acres had been planted to corn in Worth and Cerro Gordo counties prior to Thursday May 17, but finally some drier conditions and spotty shower activity allowed farmers to start field operations and planting over the past weekend. I would estimate 50% of the corn is planted in that area and fieldwork, spraying and planting was going strong today (Tuesday, May 22) east of Interstate 35. Nearly all the corn is planted from Hwy 20 to Hwy 3, but only about 30% of the beans are planted, and less beans the further north you go.  And while we hope for continued dry conditions across the northern part of my area, folks in Story and Boone are hoping for a little rain. Corn ranges from VE to V3 in Story County and I have seen some V1 beans in Webster County.  Emerged corn looks good, and have a had a few reports of bean leaf beetle feeding."

Northeast Iowa

Terry Basol (Region 4): “Last week’s dry weather conditions really helped farmers in NE Iowa with corn planting progress. From last Wednesday (May 16th) through Sunday (May 20th) provided farmers in Northeast Iowa to get up to 80% and 52% of the corn and soybeans planted respectively, according to the . Most all of the southern half of my territory is finished planting corn and has a very good start on soybean planting. Early planted corn has emerged and shows to be in the VE to V1 and some in the V2 stage. Soybeans have also begun to emerge in the southern area with most in the VC stage. The farther north you go, or closer to the Minnesota border, the less corn that’s planted. Growers in the northern counties continue to be challenged due to excessive soil moisture conditions. Most growers in this area of the state were able to get some corn planted as well due to the favorable weather we had last week."

Corn planting continues at the NE IA Research and Demonstration Farm by Nashua, IA. Photo by Terry Basol. 

Southwest and West Central

Mike Witt (Region 11): “In West Central Iowa, corn generally looks good with almost all fields planted. The corn is at a growth stage of anywhere from not emerged to V4. I have seen a few issues with planting into colder fields and herbicide problems but in general stands look good. Soybeans are around 80% planted with a few fields emerged or starting to emerge. The projected weather pattern of warmer temperatures and good precipitation look to provide good upcoming growing conditions. Some alfalfa fields I have monitored in the area are on pace for first cutting to occur during the first week of June. Spraying of fields is also in full swing with weather conditions determining which fields can be covered. Overall for this week, I expect planting and spraying will continue at the rate that spotty rain storms will allow.”

Southeast and East Central:

Rebecca Vittetoe (Region 8): “Rainfall was spotty across the south-central area over the last week, with some areas receiving a trace to other areas receiving a couple of inches. Corn planting has basically wrapped up, and corn ranges anywhere from just emerged to V4. Soybean planting is probably 85 to 95% complete in the area. Some of the earliest planted soybeans are at the VC stage already. Overall fields are looking pretty good. It’s a good time to get out and evaluate how stands are looking. This includes doing stand counts to compare seeding rates to plant populations; looking for potential insect, weed, or herbicide injury problems/issues; and checking for any planter issues, such as inconsistent planting depth or plant spacing issues. I have received calls and looked at corn fields with fomesafen carryover from last year. Usually it’s been in fields were fomesafen was applied late or in overlap areas. Most of the corn should grow out of it. Pastures and alfalfa fields are looking pretty good, but we’ll need consistent rain throughout the growing season to keep them going. As of May 22, alfalfa at the ISU McNay farm is measuring 28 to 30" tall and is just starting to form buds. The PEAQ relative feed value would for this alfalfa averaging 28" to 30" tall ranges from 163 to 171 if no buds are visible and 156 to 164 if buds are visible.”

The veinal chlorosis and necrosis on these corn seedlings from a field in Mahaska County is a common injury symptom in corn of fomesafen carryover. Photo by Rebecca Vittetoe. 

Josh Michel: “Rainfall was scattered in this part of the state. While the rain did help improve soil moisture conditions were it did fall, subsoil moisture levels are still low. Corn is basically all planted and ranges from just emerged to V3 to V4. Soybeans are about 90 to 95% planted, and the farthest along soybean field I’ve seen is VC. It’s a good time to get out and evaluate stands Alfalfa fields are around 24” tall or slightly taller. I haven’t seen any buds yet, but expect to see budding later this week. This equates to a PEAQ relative feed value of 190.”

Meaghan Anderson (Region 9): “Most corn is out of the ground, with the largest corn I've seen at V3. Most soybeans are just at VE stage, but I saw one field at VC stage late last week. Once crops are up, early season scouting and stand counts can begin. Stand counts allow you to compare your stand with seeding rate and look for anything unusual with the field. Overall, corn stands look really nice, with more consistency in many fields than last spring. While you're out scouting, keep an eye out for bean leaf beetle feeding in the earliest-seeded soybean fields. In corn, weeds are coming on strong and will need POST herbicides soon, scout for black cutworms and other early-season insect pests, such as armyworms, and keep an eye out for herbicide carryover from last year's late fomesafen applications in soybeans. Luckily, most corn with fomesafen carryover will recover after a few leaves with no issue.”

Weed seedlings are starting to show up in fields. Be scouting and make timely POST herbicide applications. Photo by Meaghan Anderson. 

Virgil Schmitt (Region 10): “In the last two weeks we have receive 1 – 3 inches of rain over most of the counties I cover. Corn is mostly V2 to V3 with fields on both sides of that. In general stands look very good and healthy. Soybeans are mostly yet to emerge to VE. Again, stands look good and healthy.”

Rainfall totals across Iowa for the past two weeks. Source: https://water.weather.gov/precip/

Find your local ISU Extension and Outreach field agronomist here!

Category: Crop ProductionTags: field agronomistscrop updateplantingemergenceAuthor: Rebecca Vittetoe

True Armyworm Trapping Update

Tue, 05/22/2018 - 08:42

True armyworm is a migratory pest that arrives in Iowa from southern states and lays eggs on living tissue. Adult females are attracted to fields with green plants, particularly weedy grasses or living cover crops. These plants serve as initial feeding sites for larvae. When these original host plants are no longer available (defoliated or terminated by herbicide), larvae move to adjacent corn plants. On corn, larval feeding begins on the lower leaves and continues up the plant as leaf tissue is removed (Photo 1). Larvae can be found in the whorl of young, injured plants. Fields with crop residue or a living cover crop should be scouted for true armyworm once corn has emerged. Significant stand losses can occur with true armyworm infestations.

Photo 1: Typical true armyworm feeding injury on corn. Feeding begins at the leaf margins, and larvae will consume everything except the tough midrib. Photo copyright Adam Varenhorst.


True armyworm larvae can be identified by dull orange stripes along each side of their body (Photo 2). They also have four fleshy prolegs with dark bands on their abdomen in addition to six legs on the thorax. Larvae have an orange head capsule with black lines. Adults are identified by a white spot in the middle of the wing and a solid dark line at the edge of the wing that becomes spotted toward the middle (Photo 2).

Photo 2: True armyworm larvae (left) can be identified by dull orange stripes along each side of the body, banded prolegs, and orange head capsule. Photo copyright Adam Varenhorst. True armyworm adults (right) can be identified by the white spots in the center of each wing and dark line from the edge of the wing. Photo courtesy of University of Missouri IPM.

Trapping Network:

Each spring, cooperators around the state host true armyworm traps, which are wing-style traps with a pheromone lure. These traps capture adults (moths) and can inform us where we can expect to see true armyworm activity around the state. Trapping began April 1 and will continue through May. It is important to note that true armyworm is a sporadic pest and scouting is necessary to determine if they are present in a particular field and whether treatment is necessary. Below is a summary of weekly true armyworm activity by county:


For corn seedlings (VE-V2), recommendations for foliar insecticide applications occur when 10% or more of the plants are injured and larvae are less than ¾ inch long. When corn is V7-V8, treatment should be considered only if larvae are ¾ inch long with greater than 8 larvae per plant and 25% of leaf area has been removed. Larvae this size are expected to feed for another week and may cause more injury. 

Category: Crop ProductionInsects and MitesTags: armywormpest scoutingcorn pestsAuthors: Adam SissonErin HodgsonCrop(s): Corn

Monarchs on the Move Challenge Touring Iowa this Summer

Mon, 05/21/2018 - 09:47

The 4-H Ag Innovators Experience Monarchs on the Move challenge tour is underway in Iowa, and geared up to hit over 70 events throughout the remainder of the spring and summer. So far, the tour has stopped in nine locations for Science, Technology, Engineering and Mathematics (STEM) field days and events, with many more to come.

The Monarchs on the Move challenge is the result of a collaboration between the National 4-H Council and Monsanto to create the 2018 4-H Ag Innovators Experience (4-H AIE). Youth will interact with live monarch eggs, caterpillars, butterflies and chrysalises from the USDA monarch colony at Iowa State University. The Iowa State University Integrated Pest Management program (IPM) and Iowa State University Extension and Outreach will assist in carrying out all programs around the state.

At each event, students and children will learn about monarch butterflies and the importance of pollinators in crop and food production. Students will also participate in discussions and activities with the intentions of learning about preserving the monarch population and increasing biodiversity in general.

Youth will work together to simulate and understand the life stages of a monarch butterfly, and the difficulties of survival as a caterpillar. Students and children will learn to evaluated a satellite landscape image to identify opportunities to increase biodiversity, and make recommendations for improvement while ensuring productive crop fields. As part of the 4-H AIE, event-area teens will assist Iowa State University Extension and Outreach coordinators in teaching youth.

The purpose of the Monarchs on the Move challenge is to help develop critical workforce skills in young people, to show that agriculture can be relevant and fun, and to teach about the importance of biodiversity. Students and children in Illinois, Iowa, Kansas, Missouri and Nebraska will have the opportunity to participate in the Monarchs on the Move Challenge throughout the spring and summer as part of the 4-H AIE.

To see if Monarchs on the Move will be visiting and area near you, please visit facebook.com/lovethemonarch and view the “events” listing.

Category: Insects and MitesTags: monarchsAuthor: Ethan StoetzerVideo: 

May Maize Maladies

Fri, 05/18/2018 - 08:31

Cool conditions during planting season increase the potential for herbicide injury to seedlings due to slow emergence and reduced ability of the crop to metabolize herbicides. While herbicides may be responsible for emergence issues, most problems that have been brought to our attention seem to be primarily due to the environmental conditions rather than the herbicide.

A symptom associated with Group 15 herbicides is improper unfurling of leaves as corn emerges. This injury is less frequent now than in the past since many of these products now include safeners, plus the availability of effective postmergence herbicides has resulted in many growers reducing rates.  Improper unfurling of corn leaves has been attributed to other phenomena as well, including cloddy soils, compaction or soil crusting, cool and wet soils, and wide fluctuations in soil temperatures.  

A field in southeast Iowa exhibited symptoms of improper unfurling of leaves on corn plants; the injury had no apparent pattern, affecting plants at random and accounting for about 5-10% of the total stand.  Some plants were twisted or corkscrewed underground, while others were buggy whipped at the soil surface (Figure 1 and 2). This field was planted on April 24 and sprayed with 2.8 qt per acre of Harness Xtra 5.6L on April 28. Following planting, nighttime low temperatures remained cool until early May, but daytime temperatures reached highs in the 70s or 80s.  Planting depth varied quite widely across the field, with some seed planted more than 2.5 inches in the ground and others less than 1 inch depth.  Prior to noticing symptoms, the farmer also rotary hoed this field as is his standard practice in the spring; this resulted in some emerged seedlings being reburied in the soil.

Figure 1.  Buggy whipping can be caused by envirnomental conditions, Group 15 herbicides, or a combination of factors.

Figure 2.  Emergence problem attributed to environmental stress.

Abnormal growth often is caused by a combination of stresses, and in many cases it is difficult, if not impossible, to identify which factor is the primary culprit.  While we cannot rule out the possibility that the herbicide played a role in the issue in this field, we suspect the environment and management practices were the leading factors involved in the emergence problems.  An additional stressor in this particular field was the presence of fomesafen (Flexstar et al.) carryover injury.  Fomesafen causes veinal necrosis on leaves, and the damage to the midvein often causes early leaves to ‘collapse’ (Figure 3).  These symptoms were only evident at the entry of the field, indicating that the carryover likely was due to overapplication in this part of the field. Due to the lack of fomesfen symptoms in other areas of the field, we don’t think it contributed to the improper unfurling seen throughout the field.

Figure 3.  Veinal necrosis typical of fomesafen carryover.

There have been numerous reports of fomesafen injury to corn recently.   Since fomesafen is broken down more quickly with wetter soil conditions, some injury following last summer’s dry weather is not surprising in spray overlap areas or where a heavier rate was applied.Past experience suggests the corn will rapidly grow through this injury, but there always are exceptions. The increased use of ‘rescue’ treatments made into July to control waterhemp is the primary factor leading to these problems.  There is a 10 month rotation restriction for corn following fomesafen use, so the product shouldn’t be used in July in most situations.   The inclusion of residual herbicides (group 15 products) with early-postemergence application and/or planting narrow-row soybeans are the simplest strategies to limit the need for rescue treatments.

Corn in a field in southwest Iowa emerged normally, but then began to rot from within the whorl following a heavy rain (Figure 4).   The damage was spotty throughout the field, but where present 5 to 10% of plants were affected.  Since no herbicides had been applied yet (not a recommended practice), there were questions whether the rain could have splashed residues from the previous year’s product into the whorl.  Based on the herbicides used during 2017 it was easy to rule this out.  Nearly all of the dying plants had significant quantities of soil inside the whorl.  The likely cause of death was bacterial infection due to the soil washed into the whorl. 

Figure 4.  Heavy rain can wash soil into the whorl, resulting in bacterial infections.

The majority of preemergence herbicides achieve selectivity based on differential metabolism – the crop detoxifies the herbicide more quickly than sensitive weeds. Any situation (shallow planting, heavy rain, misapplication) that increases the amount of herbicide in contact with the seed while it imbibes water increases the likelihood of injury.  Cool or fluctuating temperatures can also reduce the crop’s ability to metabolize the herbicide.  There are always risks when using herbicides, but the advantages they provide in managing weeds greatly outweigh these risks.

Category: WeedsTags: Cornherbicidesemergence problemsfomesafenherbicide injuryAuthors: Bob HartzlerMeaghan AndersonCrop(s): Corn

Delayed Planting Afflicted on Northern Iowa

Mon, 05/14/2018 - 18:07

Planting conditions in northern Iowa, especially north of highway 20, is experiencing delays due to abundant rainfall. Corn planting progress is currently at 40% across the northern crop reporting districts compared to 65% and 70% for the state and 5-year average (USDA-NASS). Soybean planting progress is at 13% across the northern crop reporting districts compared to 33% and 28% for the state and 5-year average. There is still time to get both the corn and soybean crop planted to achieve good yield outcomes. Here are some considerations and resources to help make decisions.


Corn planting date effect on yield and crop maturity

Corn yield begins to decline after May 15 planting dates with rapid declines after June 1. In data from a recent study from 2014-2016, corn relative maturity was an important factor for April and May planted corn where at northwest, north central, and central Iowa locations a full season hybrid achieved higher yields than shorter season hybrids. At all seven locations, the early and late June planting dates did not result in hybrid relative maturity yield differences.

Plant Density

April 20 – May 5

May 5 – 15

May 15 – 25

May 25 – June 5

June 5 – 15


relative yield (%)































Adapted from Corn and Soybean Field Guide, ISU Extension, IPM 0001.

Recommendations: Deciding on what hybrid relative maturity to plant is an important consideration when planting is delayed. The time at which corn reached physiological maturity is about a 10-day difference between a full season and short season hybrid. This is an important factor to consider to reduce fall frost risk ahead of physiological maturity as well as post-physiological maturity grain dry-down. April and early May planted corn should mature in mid-September while June planted corn would reach maturity in early to mid-October. The potential for grain dry-down in the field is lower the later corn reaches physiological maturity. This could decrease crop profitability because of higher grain drying costs.

  1. Plant the originally planned well-adapted corn hybrid through May 31.
  2. After May 31, consider planting a ~5-day earlier maturing corn hybrid.
  3. After May 31, consider crop insurance prevented planting provisions.
  4. After June 15, consider switching to soybean with consideration to already applied herbicide and nitrogen programs as well as impact on crop rotation and plans for future years.


Soybean planting date effect on yield and crop maturity

The highest yield potential for soybean production in Iowa is achieved with April to mid-May planting dates. Soybean yields begin to decline after May 20 with larger declines the later planting becomes. Soybean maturity selection is often discussed as a means of achieving higher yields, however, in late planting situations soybean grain yield is not influenced by maturity selection.

Planting Date

Northern IA

Central IA

Southern IA


relative yield (%)

Late April




Early May








Early June








Early July




Adapted from Soybean Replant Decisions, ISU Extension, PM 1851.

Recommendations:Soybean typically reach maturity in mid to late September regardless of planting date. Soybean physiological maturity is minimally delayed by either planting date (5- to 10-day delay) or maturity group selection (up to 5-day delay). This minimizes the need to change soybean maturity group selection when faced with late planting situations.

  1. Plant the originally planned well-adapted soybean varieties through June 30.
  2. After June 15, consider crop insurance prevented planting provisions.



Delayed and Prevented Planting Provisions for Multiple Peril Crop Insurance

Soybean Planting Decision Tool

Category: Crop ProductionTags: corn plantingcorn planted latesoybean plantingsoybean planted lateSoybean planting decision toolAuthor: Mark LichtCrop(s): CornSoybean

Regional Update: Crop planting and progress for week of April 30 through May 8

Tue, 05/08/2018 - 09:43

#Plant18 continues to progress across the state. According to Monday’s USDA Crop Progress Report, approximately 40% of Iowa’s expected corn crop has been planted and 11% of the expected soybean crop. Due to the wet weather across the state last week, #Plant18 and other field activities were put on hold as many farmers only had 2.9 suitable days for fieldwork. Iowa State University Extension and Outreach field agronomists report planting progress and field conditions in their respected regions.  

Northwest Iowa

Joel DeJong (Region 1): “In the Northwest corner of Iowa we have a mixed planting report. Some neighborhoods, mostly on the south half of the region, are half done planting corn or a little more. Some neighborhoods in the northern counties have as little as 5% done. Very few soybeans have been planted. Well drained fields have been a bonus this year, and those not well drained have been very slow to get started. There is a lot of planting left to be done. Alfalfa seemed to overwinter quite well but is behind normal in growth at this time, as are pastures. Cover crops are finally about 6 inches tall or so, and starting to take off. A longer period of dry weather would be appreciated during the next week or more, although the forecast doesn't look as rosy as that.”

North Central Iowa

Angie Rieck-Hinz (Region 3): “The week of April 30 through May 7 saw field work and planting across the southern end of my area on Monday, April 30, but also included 1.54 inches of rain at Webster City to 3.2 to 3. Inches of rain from Mason City to Hampton. I would estimate 80% of the corn is planted from Hwy 30 to Hwy 20; 60% from Hwy 20 to Hwy 3; 10% from Hwy 3 to Hwy 18; and less than 5% from Hwy 18 to the Minnesota border. Yesterday (May 7), I saw a few folks attempting tillage and planting near Thornton, but only on the high spots. The forecast for the week of May 7 does not look promising in northern Iowa.”  

Southwest and West Central

Mike Witt (Region 11): “West Central Iowa has seen a good run of weather for planting. Corn planting in the area is around 60% done and soybeans around 20%. More acres are planted from west to east across the area as the soils, in general, have dried up faster. Spraying has proven to be a challenge with many fields still waiting for spring applications. Weather this week will probably bring a slowing to progress as more rain is forecasted.”

Southeast and East Central:

Rebecca Vittetoe (Region 8): “Some much needed rain fell across South Central Iowa last week with most areas getting at least 0.5 inch to an inch of rain. I would estimate that approximately 75% of the corn is planted in this part of the state and 30% of the soybeans have been planted. The first planted corn (around April 23) has emerged and is at VE to V1. Pastures and alfalfa fields have been slow at getting much growth this spring, but last week’s rains helped. We are on the dry side here with only having less than half to 25% percent of normal rainfall for the month of April. This part of the state could definitely benefit from some more rain, which there is some in the forecast for this week.”

Corn planted the week of April 23 emerging at the ISU McNay Research Farm in the long-term tillage plots. Photo by: Rebecca Vittetoe. 

Meaghan Anderson (Region 9): “After a beautiful start to field work two weeks ago, we got some well-deserved rain across east central Iowa in the middle of last week. Some reports were as high as 3 inches over several days, mostly in my southern counties. Farmers are just now getting back in the field to continue planting, but the first planted corn from the week of April 23 is now emerging out of the ground. Corn planting is nearly finished in my southern counties and soybean planting varies widely across my counties. Calls in the last week include questions on the timing of residual herbicides and soybean planting, weed identification, alfalfa stand evaluation, and cover crop termination.”

Virgil Schmitt (Region 10): “Corn planting started in earnest on April 23 in my southern counties and was going strong in my northern counties by April 25. Planting continued through May 2 in most places and started again over the week end. We receive anywhere from 0.5 to 2+ inches of rain since Thursday of last week. Corn is 95% or more planted in my southern counties and about 80% complete in my northern counties. Soybean planting is about 25% complete in my southern counties and about 10% in my northern counties. First planted corn is in the VE to V1 stage. Mustards and dandelions are in full bloom.”

Map showing rainfall totals for Iowa over the last week as of May 7, 2018. Source: http://www.weather.gov.  

Find your local ISU Extension and Outreach field agronomist here!

Category: Crop ProductionTags: field agronomistscrop updateplantingAuthor: Rebecca Vittetoe

No, you aren’t seeing western corn rootworm adults right now

Mon, 05/07/2018 - 11:31

Over the weekend, someone let me know they saw a western corn rootworm adult. Remember this pest overwinters as an egg that hatches in June! They get confused with closely-related species every spring: striped cucumber beetle. Striped and spotted cucumber beetles overwinter as adults and become active when spring temperatures warm up. Most scouts are able to distinguish northern corn rootworm and southern corn rootworm (also known as spotted cucumber beetle) fairly easily. However, western corn rootworm and striped cucumber beetles can be distinguished by the stripes on the forewings.

Western corn rootworms are yellow with a dark head. Females have three black lines on the forewings that do not extend to the wing tip. The forewings of males often look like a black smudge (note one male in this photo). Photo by Purdue Extension.

Striped cucumber beetles are yellow with a dark head and have three crisp dark lines on the forewings that extend all the way to the wing tip. Photo by Jim Jasinski, www.ipmimages.org.

Spotted cucumber beetle (southern corn rootworm) are yellow with a dark head and have 11 black spots on the forewings. Photo by Jim Jasinski, www.ipmimages.org.

Left to right: southern corn rootworm (spotted cucumber beetle), western corn rootworm, and northern corn rootworm. Photo by Adam Varenhorst. 


Category: Crop ProductionInsects and MitesTags: pestbeetlerootwormAuthor: Erin HodgsonCrop(s): Corn

New Midwest stink bug app now available

Wed, 05/02/2018 - 06:54

A free app is now available to simplify the early detection of brown marmorated stink bug in the Midwest. This new invasive species has a wide host range, including soybean, corn, apples, tomatoes, grapes and peppers. App features include:

  • A stink bug "look alike" page that helps users distinguish stink bugs from non-stink bugs
  • New artwork designed to assist users in finding the distinguishing features of stink bugs
  • High-quality, high resolution images of common stink bug species in the Midwest
  • Additional resources for specific crop impacts and BMSB management are included

The app can be used on IOS and Android platforms. The app was developed by the University of Minnesota Extension IPM Program in partnership with the Minnesota Invasive Terrestrial Plants and Pests Center and Purdue University. Contact Bill Hutchison, University of Minnesota, with any questions (Email: hutch002@umn.edu).

Brown marmorated stink bug. Photo by Natasha Wright (www.ipmimages.org). 

Brown marmorated stink bug. Photo by David R. Lance (www.ipmimages.org). 

Category: Crop ProductionInsects and MitesTags: stink bugscoutingIPMpestAuthor: Erin HodgsonCrop(s): CornSoybean