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Subscribe to RSS FeedAccelerated, early planting in some parts of the state increases pressure on applicators of preemergence herbicide to speed up sprayers to cover a larger numbers of acres. Increased speeds increase boom pressure for existing nozzles, and can tempt applicators to increase boom height. Both...
Clarke McGrath
April 25, 2016 11:52 AM
Corn typically requires 90 to 120 Growing Degree Days (GDD) from planting to emergence. Of course this GDD range assumes adequate soil moisture and varies with planting depth, tillage system and residue cover. As a rule of thumb, if 120 GDD have accumulated since planting and seedlings haven’t...
Had a question why winter annuals, specifically henbit, are so thick this year. Two main factors: 1) ample moisture at the end of last year's growing season, and 2) a relatively mild winter. Most winter annuals emerge in late August-September, in many years we don't have enough soil moisture...
Rebecca Vittetoe
April 20, 2016 1:25 PM
I’ve received a few questions asking what the purple weed is that is appearing in the landscape. It is probably either purple deadnettle (Lamium purpureum) or henbit (Lamium amplexicaule).
These weeds often get confused because they look similar. They both belong to the...
Alison Robertson
April 20, 2016 11:12 AM
Many of you are aware that a few years ago we collected diseased soybean seedlings from fields across the Midwest and identified organisms associated with the rotted roots. This soybean seedling disease survey was funded by USDA-NIFA and soybean check-off and the identification of the organisms...
Meaghan Anderson
April 20, 2016 10:24 AM
I received one report of a cereal rye control failure this week as temperatures warmed and rye growth resumed. Some follow-up questions and photos showed that concerns regarding burndown applications during cool, early-spring conditions have merit.
A southeast...
The recent rainfall broke a string of dry days for us. Spencer received about 0.7 inches of rain. Storm lake, Spirit Lake and other areas in the highway 71 corridor received a similar 0.4 to 0.7 inches. However, areas east of Highway 4 did not receive much rain and are returning to the field...
The focus has been on planting corn, but don't forget about the weeds. In addition to getting preemergence herbicides applied to the corn acres, burndown applications on no-till soybean fields should be a top priority. Timely application of burndown herbicides simplifies controlling many winter...
Overall, planting was variable in many parts of the state from Wednesday, April 13, to Sunday, April 17. After five days of great weather and good seedbed conditions, some farmers are completely done with corn, some were able to begin and reach the halfway mark, and others are still doing...
Weather conditions this past week (April 13-17) kicked off corn planting for many farmers throughout the state. As soil temperatures rose above 50°F towards the end of the week, farmers were able to dive into fieldwork and planting corn.
See statewide planting progress and field...
Alison Robertson
April 15, 2016 11:12 AM
A couple of weeks ago in a blog post, I shared with you some research we are doing on the effects of cold stress on soybean susceptibility to seedling...
Meaghan Anderson
April 14, 2016 10:05 AM
John Sawyer
April 14, 2016 10:05 AM
It seems that anhydrous ammonia (AA) applications and planting may fall very close together on the timeline of events this spring. This could be concerning with drying soils and lack of significant rainfall chances in the near future.
Important notes to remember:
1) Application...
Mark Licht
April 11, 2016 2:08 PM
Planting season is or soon will be underway. This presents an opportunity to talk about a few things; 1) ideal conditions for planting, 2) seeding depth, and 3) imbibitional chilling.
Planting conditions
Ideal planting conditions are when the soil temperature...
Erin Hodgson
April 11, 2016 1:53 PM
In March, I posted a blog about alfalfa weevils laying eggs in SE Iowa. Degree days have been slowly accumulating in April. I've updated the degree day map for 2016 and alfalfa weevils should be...
A 'true' weed ecologist probably would have shuddered at my explanation to young 4-H'ers how weeds survive our control efforts:
1) shake them off (giant ragweed) or 2) overrun them with numbers (waterhemp).
...
Clarke McGrath
April 7, 2016 8:58 PM
I've had a lot of questions/discussions this week about planting corn. I had some growers get started Monday, some others were going to start towards the middle or tail end of this week, a few were going to wait until Monday, and a few were undecided. When to start planting was probably...
Erin Hodgson
April 5, 2016 1:39 PM
Adam Sisson
April 5, 2016 1:39 PM
Bean leaf beetle adults are susceptible to cold weather and most will die when the air temperature falls below 14°F (-10°C). However, they have adapted to winter by protecting themselves under plant debris and loose soil. An overwintering survival model developed at ISU in 2000 is helpful for...
The rapid spread of herbicide resistant weeds threatens the current Midwest production system. Introduction of new herbicide resistance traits will provide additional management options for resistant-prone weeds such as waterhemp, giant ragweed, and marestail; however, these systems must be used...
Alison Robertson
April 4, 2016 2:31 PM
Mauricio Serrano
April 4, 2016 2:31 PM
Research can be frustrating. For the past 5 years, my lab has been evaluating seed treatments on soybean. In an effort to detect an effect of seed treatment on soybean stand and yield, in 2015 we planted our trials very early (mid-April). A few days later, it rained, soil temperatures dropped...
Angie Rieck-Hinz
March 28, 2016 4:45 PM
As I did some reading in preparation of writing this blog, I found there are various definitions of soil health. And I am sure for as many definitions as there are, we each have our own ideas as to what defines soil health. The USDA-NRCS Soil Health web page defines soil health as "the continued...
Erin Hodgson
March 28, 2016 8:52 AM
You may have heard of brown marmorated stink bug (BMSB), an invasive insect making its way across the U.S. The first live detections of BMSB in Iowa were in 2011. Laura Jesse, Director of the Plant and Insect Diagnostic Lab, has now confirmed BMSB in 12 Iowa counties (see a map...
Clarke McGrath
March 25, 2016 6:10 PM
Meaghan and Bob’s blog posts on weeds, and seeing a floater spraying yellow herbicide in 30 mph winds on Monday, reminded me to do an update on our newest problem child in the weeds world, Palmer amaranth. While we hoped that the few infestations scattered across Iowa could be contained,...
Erin Hodgson
March 24, 2016 11:37 AM
Adult alfalfa weevils begin moving as soon as temperatures exceed 48°F and begin laying eggs in alfalfa. Alfalfa weevil eggs develop based on temperature, or accumulating degree days, and hatching can start around 200-300 degree days. Start scouting alfalfa fields south of Interstate 80 at 200...
Meaghan Anderson
March 17, 2016 11:51 AM
Spring seems to have sprung early this year with the beautiful weather and very warm temperatures. I like to take a lap around the office on the Johnson County Fairgrounds a few times during the...
Daren S Mueller
March 16, 2016 7:15 PM
Alison Robertson
March 16, 2016 7:15 PM
Alison and I spent the week editing the nearly final version of two national publications about corn and soybean diseases. These will be published by our society, APS Press, like the Fungicides for Field Crops ...