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Extension > Minnesota Crop News > June 2009

Tuesday, June 30, 2009

Losses in Wheat due to Flooding and Waterlogging

Jochum Wiersma, Samll grains specialist

Northwest Minnesota continues to be plagued by excess precipitation. Consequently many field or lower lying portions of fields are repeatedly flooding or are - at a minimum - completely waterlogged. Flooding and water logging causes a rapid depletion of oxygen in the root zone. In turn, this oxygen deficiency affects several physiological processes such as the uptake of water, the uptake and transport of nutrients, and the root/shoot hormone relations.

Wednesday, June 24, 2009

Soybean Rust: What will this year bring?

by Phillip Glogoza, Extension Educator - Crops

Soybean rust was found in 392 counties in the United States in 2008. This is the highest number of counties reporting the disease since it was first discovered in the continental U.S. in 2004. Soybean growers in Alabama were encouraged to use fungicides on at risk beans in late August, many neighboring states reported mostly low infection levels throughout the month of September as the crop matured.

Alfalfa Weevil: Coming on Strong in West Central MN

by Doug Holen, Extension Educator - Crops, Fergus Falls
and Phillip Glogoza, Extension Educator - Crops, Moorhead

Just a quick note to report a significant outbreak of alfalfa weevil in WC MN. It escalated over the weekend with a lot of spraying starting on Monday. We have fields in all stages with 1st crop still standing, cut alfalfa in windrow for some time, and 16" of 2nd crop regrowth. All fields have been hit hard. All alfalfa growers in west central MN should be checking for possible infestations.

Saturday, June 20, 2009

Consider Narrow Rows for Higher Corn Yields in West-Central and Northwest Minnesota

By Jeff Coulter, Extension Corn Agronomist; and Lizabeth Stahl, Extension Educator - Crops

Now is a great time to consider modifications to your corn production system for 2010. A key step to higher corn yields may be narrow rows (narrower than 30 inches). Planting corn in narrow rows increases the within-row distance between plants, which in theory helps minimize competition among plants for water, nutrients, and light. This is particularly true in the northern Corn Belt, where the shorter growing season and cooler air temperatures can limit crop yield potential. For corn growers contemplating narrow rows, consider the following.

Thursday, June 18, 2009

Sunflower Rust Fungus is Alive and Well in Minnesota and North Dakota

By Dr. Charla Hollingsworth, Plant Pathologist, U of Minnesota Extension
and Dr. Sam Markell, Plant Pathologist, NDSU Extension Service

This past week, the fungus that causes rust on sunflower, Puccinia helianthi, was identified on wild and volunteer sunflowers in Minnesota and North Dakota. The rust fungus is known as a "macrocyclic" pathogen because it produces five successive types of spores during its lifecycle. While all five types of spores are produced on sunflower, only one type is responsible for causing rust epidemics.

Wireworms in Small Grains

by Dr. Ian MacRae, Extension Entomologist

I've received reports of wireworms in small grains this season - not surprising this year given that wireworm tend to be more active in cooler conditions. There are several species of wireworms in the Red River Valley and although they're usually neither a frequent nor wide-spread problem in the RRV, when they do occur, damage can be quite significant even leading to a total field loss.

Controlling Canada thistle with Milestone

By Carlyle Holen, IPM Specialist, U of Minnesota Extension

Can_thstl.jpg
What is the optimum time to treat Canada thistle (Figure 1) in non-cropland with Milestone? Based on field trials at Ada in 2007 the window for application is pretty wide and perhaps a better way to frame the question might be: What is the least effective time to treat Canada thistle?

Cool Temperatures Delay Alfalfa Weevil: Time to Scout Fields in NW MN

By Phillip Glogoza, Extension Educator - Crops

The cool temperatures have delayed alfalfa weevil population development in the region. In west central MN, first cut got underway two weeks ago. As we move northwest, first cut may just be beginning for some. In some cases, cutting alfalfa may have removed significant eggs laid in stems, while in other sites young larvae are feeding in the growing terminals, whether it is regrowth or uncut alfalfa.

Tuesday, June 16, 2009

Causes of Seedling Stand Losses in Spring Wheat

Jochum Wiersma, Small grains specialist

Seedling stand loss is defined as the percentage of viable seed that fails to become a healthy plant. In order to understand the causes of stand loss we need to also define seedling vigor. Seedling vigor is defined as those seed properties that determine the potential for rapid, uniform emergence and development of normal seedlings under a wide range of conditions. Causes of seedling stand losses can be categorized in three broad categories - intrinsic attributes, biotic stresses, and abiotic stresses.

Friday, June 12, 2009

Continuous Corn in Minnesota: How do we do it?

by Ryan Miller and Brad Carlson, Extension Educators – Crops

In 2008 University of Minnesota Extension launched an on farm research project evaluating continuous corn production under a series of different tillage systems on six farms across Minnesota. For the sake of brevity this article will only address one site in Southeastern Minnesota that is located near Faribault.

The tillage systems studied include a conventional moldboard plow system, a chisel plow system representing a traditional conservation tillage, and strip till as a higher residue conservation tillage system.

Now is The Time to Evaluate Stands

Jochum Wiersma, Small grains specialist

The challenging spring in Northwest Minnesota has forced many to seed their wheat and barley under less than ideal conditions and into poor seedbeds. Now is the time to evaluate how well your seeding operation went and what the attained stands are. This is important as the decision about inputs further into the season will depend on the yield potential that is left.

Stand counts are simple to do and take just a little extra effort while you are scouting for weeds and/or early season fungal diseases. The easiest time to do a stand count is probably when the crop is in the two- to three-leaf stage since tillers are not visible yet, and counting is easier.

Glyphosate nonperformance issues and glyphosate-resistant biotypes

Glyphosate-resistant biotypes of giant and common ragweed and common waterhemp have been confirmed in Minnesota and are listed on the International Survey of Resistant Weeds web site at: http://www.weedscience.org/in.asp Both species appear to be resistant to approximately four-times the labeled use rate of glyphosate (4X).

In the short time frame presented to us during the growing season, separating glyphosate nonperformance due to resistant weed biotypes from other factors is an inexact and qualitative process but a quick response could help reduce the spread of glyphosate resistant weeds and set-up long-term management plans.

Thursday, June 11, 2009

Temperatures Affect Glyphosate Activity

Temperatures over the last month have fluctuated greatly. Cold temperatures two weeks ago caused a reduction in glyphosate activity. Individual plants of lambsquarters and annual smartweed species where not completely controlled at a research location while other plants and other species were completely controlled. Cold weather in early June of 2008 also caused a reduction in glyphosate activity. The cold weather last week and early this week will likely cause glyphosate applications to be less effective until warmer temperatures persist.

Soybean Planting Date and Delayed Planting

sybn_plnt_dat_mat_comp.jpg
We are into the fourth year of a soybean date planting trial at Crookston investigating how two different relative maturity soybean varieties respond to planting date. Results for 2006 - 2008 show maximum soybean yield when planting in the May 1 - 15th window of opportunity. Previous planting date trials from the University of Minnesota also show an optimum planting window of May 10 - 20 to achieve maximum yield (Table 1).

Orange Wheat Blossom Midge: Vigilance is in order

WM_adlt_larv.jpg
Orange wheat blossom midge (Figure 1) as a wheat pest has been off the front page as a major production problem in NW MN for many years. Populations in the region have been small enough that significant outbreaks and associated yield losses have been of small concern. However, we learned in the mid-90’s that given the right circumstances, this insect can increase its population rapidly and cause major yield losses in a very short time frame.

Thursday, June 4, 2009

Volunteer Corn Management in Corn and Soybean

Large populations of volunteer corn are being reported in some fields in Minnesota this year. What impact the volunteer corn will have on this year’s crop yield and the viable management options available will depend upon in which crop the volunteer corn is present. Making the assumptions that the majority of the volunteer corn present is glyphosate resistant and that glyphosate resistant crops were planted in the field this year, your only management option in corn at this time is cultivation. In soybean you have the herbicide options of the ACCase inhibiting herbicides such as: Select Max (clethodim), Fusilade DX (fluazifop-P), Fusion (fluazifop-P & fenoxaprop) and Assure II (quizalofop); note Poast Plus (sethoxydim) is not as active as the other herbicides on volunteer corn. The ACCase inhibiting herbicides are generally targeted on 12- to 24-inch tall volunteer corn. The ALS herbicide, Raptor can also effectively control smaller (2 to 8 inch) volunteer corn.

Tuesday, June 2, 2009

Blending of Wheat Varieties - II

Jochum Wiersma, Small grains specialist

In a previous article that appeared in Prairie Grains Magazine and the Farm & Ranch Guide blog, I discussed the merits of blending different varieties of spring wheat. The harsh winter and spring have added another dimension to this discussion that demands some attention.

When blending two different hard red spring wheat cultivars, you will be able to market the harvested grain as one of your classes of hard red spring wheat defined by the U.S. Grain Grading Standards.

Many winter wheat stands were damaged as a result of the cold winter or the water and flooding this spring. Consequently, many producers have opted to reseed the damaged portions of winter wheat fields with spring wheat. In many cases this resulted in spring wheat being interseeded with winter wheat.

2009 Central MN Alfalfa Scissors Cut Project 6/02/09

2009 Central MN Alfalfa Scissors Cut Project - 6/2/09 (pdf)

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