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Extension > Minnesota Crop News > April 2016

Friday, April 29, 2016

Early Season Yellowing of Wheat, Barley, and Oats.

Reports of yellowing in small grains have started to reach me. There are several reasons why young wheat, barley, or oat plants have a pale green/yellow color. Some of the more common causes of early season yellowing are:

§  Nitrogen deficiency
§  Sulfur deficiency
§  Early tan spot infections
§  Herbicide injury
§  Barley yellow dwarf virus (BYDV) infections

Nitrogen (N) deficiencies can readily be identified as the symptoms are worst on the oldest leaves and start at the tip of the leaves, progressing towards the base as the deficiency gets worse. The causes of the N deficiencies are several, all which have common denominator, namely excess precipitation. Excessive rainfall causes leaching, denitrification, and an inability of the plants to take up available N.

Sunday, April 24, 2016

2016 University of Minnesota Field School for Ag Professionals Registration is Now Open


 By Dave Nicolai, IAP Program Coordinator

The 2016 Field School for Ag Professionals will be held on July 26 - 27 at the University of Minnesota Agriculture Experiment Station, St. Paul Campus, University of Minnesota. The St. Paul campus, located in Falcon Heights, MN next to the Minnesota State Fairgrounds at Larpenteur and Gortner Ave, is this year's site for the Field School for Ag Professional which is the summer training opportunity that combines hand-on training and real-world field scenarios that no winter program can offer. The two-day program focuses on core principles in agronomy, entomology, weed and soil sciences on the first day to build a foundation for participants and builds on this foundation with timely, cutting-edge topics on the second day.

Wednesday, April 20, 2016

A multi-site study on the effects of seed treatments on soybean yield and soybean cyst nematode reproduction - 2015 results


Bruce Potter - Extension IPM Specialist,  Senyu Chen,  Nematologist, Phil Glogoza, Extension Educator- Crops, Dean Malvick , Extension Plant Pathologist,  and Ryan Miller, Extension Educator-Crops

The soybean cyst nematode (SCN) is a serious pest of Minnesota soybean and has been managed with crop rotation and soybean varieties with resistance to SCN. This approach is becoming less effective, however, because SCN populations virulent on (able to reproduce on and damage) SCN resistant soybeans are increasingly widespread. A seed treatment biological (Clariva™ Complete, Syngenta Crop Protection®) has been labeled for management of SCN. 

Cereal aphids in small grains

Bruce Potter, IPM specialist, Madeleine Smith, Extension pathologist, and Ian MacRae, Extension entomologist

English grain aphid adult
Photo 1. English grain aphid winged adult. Note the black on legs and cornicles (tailpipes).
Unusually large numbers of aphids have been reported in some winter rye and wheat crops this spring. Last week, winged English grain aphids were predominant (Photo 1), but as of this week, there are already a few nymphs. Also present were a few nymphs and adults of bird cherry-oat aphids (Photo 2). Another cereal infesting aphid species, which is less commonly observed in MN, is the greenbug.

Tuesday, April 19, 2016

Managing risk when using herbicides and cover crops in corn and soybean

By Lizabeth Stahl, Extension Educator – Crops, Jeff Gunsolus, Extension Agronomist – Weed Science, and Jill Sackett-Eberhart, Extension Educator - Ag Production Systems

Print-friendly version (569 K PDF)

As more farmers look to plant cover crops in their corn and soybean fields, the question “What should I do about my herbicide program?” often arises. There is not a one-size-fits-all answer to this question, and unfortunately there are many unknowns.

Decision Time for Winter Cereal Stands

One of the hardest decisions with growing fall rye, winter wheat, or winter barley is evaluating the amount of winter kill and making the decision whether to keep a stand. Winter cereals are planted in the fall and develops in the spring during relatively ideal conditions for tiller development. Therefore the optimum plant stands of winter cereals can be less than that of their spring counter parts. A stand of 900,000 - 1,000,000 plants/acre or 21 - 23 plants/ft2 will be enough to maximize grain yield.

Thursday, April 14, 2016

Read the pesticide label for safety's sake

By Lizabeth Stahl, Extension Educator - Crops

Reading over the pesticide label is a key step in having a safe and productive cropping season. Even if you think you know a product well, read over the label each time you purchase and handle the product, as the label may have been updated, your practices may have changed, and because it can simply be difficult to remember all the details included on a pesticide label. Be sure to check the label that is attached to the container you are using as internet labels may differ. Reading over the label can help ensure the safety of yourself and others, the crop, the environment, and the food chain.

Tuesday, April 12, 2016

Corn planting decisions to establish a foundation of success

by Jeff Coulter, Extension corn specialist

Favorable soil temperature


Germination of corn requires that seed imbibe 30% of its weight in water and that soil temperature be 50°F or warmer. More time between planting and emergence increases the potential for stand establishment problems, since imbibition of water by seed is not greatly influenced by soil temperature. Risk of stand establishment problems is reduced if soil in the seed zone has reached or is near 50°F at planting and is expected to warm.

Spring management of cover crops

by Jill Sackett, Extension educator

Spring has sprung in the majority of Minnesota. It's now time to manage cover crops that were planted last summer or fall. Spring management of cover crops is as varied as the different farming operations across Minnesota. The plan of action any given farmer decides to do primarily depends on two things: 1) His or her reasons for using cover crops in the first place, and 2) the specific cover crops used.

Monday, April 11, 2016

Wheat, Buckwheat, and the Law of Unforeseen Consequences.

An interesting e-mail from the United States Department of Agriculture (USDA)  reached my desk late last week. I have cited a portion of the e-mail below.

‘The NRCS will not recommend buckwheat in conservation plantings in areas in rotation with or adjacent to commodity wheat production that will be planted to wheat within the next 2 calendar years after planting buckwheat because of the potential for buckwheat seed to contaminate the wheat crop, and the health risks that potentially poses. The use of buckwheat in conservation plantings is still permitted in fields or areas that are not used for commodity wheat production.’

Why, may you ask, has the NRCS come out with this statement and updated a number of practice standards, including # 327 – Conservation Cover, 340 – Cover Crops, and 645 – Upland Wildlife Habitat Management?

As the use of cover crops has increased in recent years, contamination of wheat shipments to Japan with buckwheat has also increased.  Unfortunately, the population in Japan has a higher proportion of people with buckwheat allergies, causing issues similar to peanut allergies in the United States.

A pretty interesting example of the law of unforeseen consequences, I think.


For more details on the rule changes, please contact your local USDA Service Center.

Thursday, April 7, 2016

Revised Michigan State Handy Bt trait table available

by Bruce Potter, IPM specialist

Most corn hybrids contain at least one transgenic trait for insect or weed control. When it comes to Bt traits, remembering which Bt event does what can be challenging. Dr. Chris DiFonzo, field crop entomologist at Michigan State University, has revised her reference for Bt traits in corn to help keep things straight.

Tuesday, April 5, 2016

Maximize the rotational benefits from alfalfa to corn

by Jeff Coulter, Extension corn specialist

First- and second-year corn following alfalfa usually benefit from increased yield potential, reduced or eliminated nitrogen requirement from fertilizer or manure, and reduced pest pressure. A recent Extension bulletin describes agronomic practices for alfalfa termination and the two subsequent corn crops that help maximize these benefits: http://z.umn.edu/rotation.

Monday, April 4, 2016

Nitrogen, Corn Production, and Groundwater Quality in Minnesota's Irrigated Sands


 Fabi├ín G. Fern├índez, John A. Lamb, and Anne M. Struffert

Corn in irrigated coarse-textured soils can be very productive with nitrogen applications, but excess nitrogen can increase groundwater contamination. To understand how much nitrogen is needed to optimize corn production and minimize the environmental impact of nitrogen fertilizers, a four-year study was done at the Rosholt Farm in Pope County and in Dakota County farmers’ fields.

Urea nitrogen rates ranged from 0 to 280 lb N/acre in 40 lb increments with half of the rate applied pre-plant and the other half at V4. Single pre-plant applications of enhanced efficiency fertilizers: ESN (a polymer coated urea), a blend of urea and ESN, and SuperU (urea with nitrification and urease inhibitors) were also studied. Lysimeters installed below the root-zone and water-balance calculations along with drain gauges were used to quantify the nitrate concentration and the amount of water and nitrate moving pass the root-zone.

Saturday, April 2, 2016

Updates to Corn Fertilizer guidelines for 2016

Daniel Kaiser and Fabian Fernandez
University of Minnesota Soil Fertility Specialists

Over the winter we have done intensive data compilation and analysis and have a few updates to the corn guidelines publication. The primary update is on nitrogen application rates for corn following corn and corn following soybean. The updated publication is not finished yet, so this article will serve as the current rate guidelines starting spring of 2016.

The current guidelines still use the maximum return to nitrogen approach. The updated nitrogen guidelines reflect additional sites of nitrogen response data collected starting in 2011 through 2015. At this time, the data have not been uploaded into the online corn N rate calculator as the site is currently undergoing a scheduled maintenance. A future article will be released when the new data are available. The guidelines in Table 1 are for corn grown on non-irrigated soils in southern Minnesota. For growers with irrigation, please refer to the publication:
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