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Managing stored grain to minimize storage losses

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by Phil Glogoza and Dave Nicolai, Extension Educators-Crops

When grain harvest approaches, it is time to review basic on-farm grain storage principles for maintaining quality of stored commodities. Harvest should include preparation of storage structures to receive grain. Preparation includes several practices that aid in preventing pest infestations from developing within our storage structures.

Multiple practices should be implemented on farm to maximize grain quality. These include using appropriate production and harvest practices, maintenance and proper use of grain handling equipment, drying systems and storage structures. There are four simple steps to maintain post-harvest quality and protect stored grains from insects, weather, rodents, self-heating, molds, mycotoxins, and pesticide residues:

  1. Sanitation
  2. Loading
  3. Aeration
  4. Monitoring

Got Weeds? Evaluate Your Weed Control Program

By Lizabeth Stahl, Extension Educator in Crops and Jeff Gunsolus, Extension Agronomist, Weed Science

By the end of the growing season, it is not too hard to spot soybean fields where weed control was less than optimal.  Prior to harvest, waterhemp can be found towering over soybean canopies throughout Minnesota.  Taking some time to evaluate effectiveness of your weed control program now can help enhance future weed control and ultimately protect yield potential and enhance profitability in the long run. 


A webinar on integrated pest management in stored grain will be offered Friday, September 12 by the North Central Integrated Pest Management Center. The two-hour webinar, which begins at 10:00 a.m. CT, will feature presentations from three entomologists in the region:

by Robert Koch, Extension Entomologist

Soybean aphid populations are increasing in some fields that were previously treated with foliar insecticides for soybean aphid.  Soybean fields should continue to be scouted until the R6.5 growth stage, even if they were previously treated.  This post-treatment scouting will allow you to catch potential resurgence of aphid populations.  When determining whether to treat an aphid infestation at this time of year, pay particular attention to plant growth stage (the economic threshold of 250 aphids per plant is valid through R5, but yield loss can occur into early R6), whether or not the aphids have wings or "wing pads" (some aphids are already moving to buckthorn, but we don't know what fraction of the population will stay on soybean), and pre-harvest intervals of insecticides.  The recent soybean aphid scouting guide provides more information.  Be on the lookout for two-spotted spider mites too.  Certain insecticides applied to control aphid populations can increase (flare) populations of two-spotted spider mites.  The spider mite fact sheet provides more information.  If a field needs to be treated again, it is advisable to switch to a different class (mode of action) of insecticide to prevent or delay the development of pest resistance to insecticides.  For more information, review the guide to insecticide resistance and resistance management.


by Robert Koch, Extension Entomologist

In July 2014, the Minnesota Department of Agriculture (MDA) published a series of best management practices (BMPs) for agricultural insecticides (link to BMPs). These BMPs were created in response to seasonal detections of chlorpyrifos in several rivers and streams in the agricultural areas of Minnesota from 2010 to 2012. Subsequently, MDA determined chlorpyrifos to be a "surface water pesticide of concern" which initiates BMP development. Some MDA samples had concentrations violating water quality standards established by the Minnesota Pollution Control Agency (MPCA) to protect aquatic life, which led the MPCA to list three water bodies as impaired due to chlorpyrifos.

Soybean aphids can now be found in many soybean fields. In some fields (but certainly not all fields) in southern Minnesota, soybean aphid populations are approaching levels requiring insecticide application to prevent economic losses. This critical soybean aphid population level, referred to as the economic threshold, is an average of 250 aphids per plant AND aphids on more than 80% of plants AND aphid populations increasing. Many fields are well below this level and do not require insecticide application for aphids at this time. Scouting is required to determine which fields require or may soon require treatment and which fields do not. A guide for soybean aphid scouting in Minnesota was recently posted (http://z.umn.edu/soybeanaphidscouting).

A Closer Look at Herbicide Rotation Restrictions

By Lizabeth Stahl, Extension Educator in Crops

What herbicides were applied earlier in the growing season can significantly influence the decision of what to do in fields or areas of a field where the original crop was flooded or hailed out.  Planting some kind of a crop can help reduce erosion potential as well as reduce the risk of fallow syndrome (see http://z.umn.edu/fallowsyndrome).  However, options can be limited if a herbicide used previously in the growing season has rotational or plant-back restrictions listed on the label.

Most of the soybean and corn crop is emerged and growing well across Minnesota.  Seedling disease problems in scattered soybean and corn fields have been reported in early June and more are expected due to wet and flooded fields.  Abundant (or excessive) rainfall and fluctuating temperatures and have created excellent conditions for seedling diseases. This is a good time to check fields for seedling disease problems and efficacy of seed treatments. 

Infection of seedlings before or after emergence can result in dead plants, rotted and discolored roots, stunted and discolored plants, and wilting.  The problems often occur in patches in fields. Seedling infection can also lead to damage that may not fully develop until mid to late summer, as with Phytophthora root and stem rot and sudden death syndrome.  Disease can cause serious damage, but it is just one of many stresses that seedlings are encountering. Careful scouting and diagnosis are often required to identify the cause of a problem.

Options for controlling emerged weeds in sugarbeet

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by Tom Peters, Extension Sugarbeet Agronomist

I have been traveling the countryside to complete spring planting, like many of our growers in North Dakota and Minnesota. I have traveled past beautiful freshly planted fields, enjoying the contrast between the green ditches and black fields. However, recent heat and rainfall have changed the landscape. One can now row emerged crops in fields. And to no-one's surprise, there are weeds in fields.

It is too early to know if black cutworm will be a significant problem in 2014 MN crop production. However, captures in a cooperative pheromone trapping network indicate vigilance is in order. We do not have complete coverage of the state with this network and cutworm infestations are always variable from field to field so it is best to err on the side of caution. Pay close attention to any leaf feeding, wilted or cut off corn plants as you scout.

There are at least two flights, April 28 and May 8, where larvae would be large enough show leaf feeding and may be large enough to cut corn in warmer locations. The highest, but not exclusive, risk for black cutworm infestations is highest from Faribault and Steele County in SC MN and a diagonal northwest up the Minnesota River to southern WC MN.

We do know that black cutworm larvae are present and active. I just received a report of black cutworm leaf feeding on corn near the Sibley/Renville County line (Curt Burns). In addition to corn, sugarbeets and several other dicot crops can be attacked.. Later planted weedy fields are were not tilled before cutworm moths arrived are most at risk. Depending on geography, weedy late worked fields may be common this year.

Scouting is important to determine if cutworms are a problem in you fields. Some corn hybrids and at plant insecticides provide control of black cutworm larvae. Insurance insecticide applications for black cutworm are not productive. For further information see: http://swroc.cfans.umn.edu/prod/groups/cfans/@pub/@cfans/@swroc/documents/asset/cfans_asset_480595.pdf .

By Lizabeth Stahl and Lisa Behnken, Extension Educators in Crops  

Access to results for many of the U of MN crops research trials conducted across the state has now become streamlined with the launch of the new, U of MN Extension Crops Research website.  This one-stop shop can be accessed through the U of MN Extension Crops webpage at www.extension.umn.edu/crops under "Research Reports".

The website contains results for small plot and on-farm crops research and demonstration trials conducted across Southern MN from 2003 to 2013.  You can also access research results for crops trials conducted at Research and Outreach Centers located across the state by clicking on the respective link.  Statewide results for weed science research can be accessed through the "Applied Weed Science" link, and results for the Minnesota hybrid and variety trials can be accessed through the "Minnesota Field Crops Variety Trials" link. 

The Research Reports webpage supplements U of MN Crops websites such as the "Corn", "Soybean", "Small Grains", "Forages", or "Sugarbeets" websites, or the "Nutrient Management", "Pest Management", "Ag Drainage", "Climate and Weather", and "Tillage" websites, where you can find research-based information and resources to help with specific crops-related decisions. 

By Robert Koch, Extension Entomologist

Recent cool and wet conditions may increase the risk of seedcorn maggot infestation in some soybean and corn fields. Seedcorn maggots are small (1/4 inch long), white maggots (fly larvae) that feed on germinating seeds. The maggots can tunnel into seed, which may result in seed death, and can injure the emerging plant tissues, which can affect plant growth or lead to damping off. Such injury can result in stand loss or weakened plants. For example, if the growing point of soybean is killed, "Y-plants" can result when branching develops at the cotyledons. Yield from "Y-plants" may be reduced if competing with neighboring healthy plants. Seedcorn maggot injury can be difficult to distinguish from other problems such as Pythium and other seedling diseases.
Fields at greatest risk are those with decaying organic matter, such as a recently incorporated cover crop or manure. Risk of injury is greater when cool and wet conditions slow germination and emergence, which increases the window of time plants are susceptible to attack. Rescue treatments are not available for this pest. However, preventative tactics can be utilized to protect seed and plants in high-risk situations. Seed-applied and soil insecticides can offer effective protection of germinating plants from seedcorn maggot (be sure to follow instructions on product label). In addition, degree-day models are available to guide decisions about adjusting planting date to avoid periods with high larval abundance (UW seedcorn maggot degree-days).
When significant stand loss occurs, replanting may be required, but this option should be considered carefully. Information is available to guide replant decisions in soybean (U of MN Extension soybean replant guide) and corn (U of MN Extension corn replant guide).

Black cutworm traps pick up significant flights

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Over the past couple weeks, cooperator-run pheromone traps indicate the potential for localized damaging populations of black cutworm in corn and other crops. Faribault, Lac Qui Parle, Swift and Waseca Counties have had significant captures. Cutting from the earliest of these flights is projected to occur after May 28.

Areas with delayed spring tillage and early season weeds are most attractive for migrant cutworms to lay eggs.

This does not mean insurance insecticide applications are warranted and insecticide rescue treatments work well where economic threshold populations occur.

2014 University of Minnesota Cooperative Black Cutworm Trapping Network newsletters with further information on cutworm biology, scouting, thresholds and control as well as maps of trap captures and cutting predictions can be found at: http://swroc.cfans.umn.edu/ResearchandOutreach/PestManagement/CutwormNetwork/index.htm


By Lizabeth Stahl, Extension Educator in Crops

Benefits of a preemergence (PRE) herbicide application in soybean were demonstrated through the "PRE Challenge" - a series of on-farm research and demonstration trials conducted across southern MN in 2012 and 2013. In these University of Minnesota Extension trials, made possible through financial support of the Minnesota Soybean Research and Promotion Council, cooperators compared a postemergence-only herbicide program to a program that included a PRE herbicide application.

By Lizabeth Stahl, Extension Educator in Crops

Does glyphosate perform as well today as it did when you first used it?  When producers were asked this question at University of Minnesota Private Pesticide Applicator Training sessions across southern Minnesota in 2014, 87% of the respondents said "No".  This percentage is up significantly from 2009, when 55% of respondents answered "No" to this question.  Increasing issues with resistance to glyphosate is likely, at least in part, behind reported reductions in weed control.  To address issues of reduced weed control with glyphosate, diversification is key. 

By Lizabeth Stahl and Lisa Behnken, Extension Educators in Crops

University of Minnesota Extension has recently launched a U of MN Extension Crops YouTube video site. It can be accessed through the newly updated U of MN Extension Crops webpage at www.extension.umn.edu/crops under "Social Media".

U of M Conservation Tillage Conference in St. Cloud, Feb 18-19

How-to information, expert advice, practical tips

By Jodi DeJong-Hughes, Extension Educator - Crops and Conservation Tillage Conference Coordinator

 

Roll up your sleeves for some practical, hands-on information that will save you soil, time, fuel -- and money. Conservation tillage is the focus of the ninth annual University of Minnesota Extension Conservation Tillage Conference and trade show Feb. 17 and 18, at the Holiday Inn and Suites, St. Cloud, MN. This conference emphasizes proven farmer experience and applied science. Straight from the trenches, learn how heavier, colder soils aren't necessarily the challenge they're made out to be. And, what have long-time no-tillers and reduced-tillage farmers learned that could spare you the same lessons?

Protect pollinators while trying to protect your crops

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By Robert Koch & Marla Spivak, Extension Entomologists

Honey bees and native bees forage in and near soybean and cornfields, especially during dry weather. When treatment decisions are being made for pests of these crops, it is important to consider minimizing the risk to these pollinators. Bees are the most important pollinators of our fruits, vegetables and crops like alfalfa hay that feed our farm animals. Honey bees and the thousands of native bee species all rely on the flowers they pollinate for good nutrition and health. Bees are being pushed to the tipping point by various factors, such as disruption of natural habitats, diseases and parasites, and widespread overuse of pesticides.

Weed Management in Prevented Planting Acres

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By Jeffrey L. Gunsolus, Extension Agronomist - Weed Science

The wet weather pattern this spring and early summer has left a significant number of acres, especially in southeastern MN, unplanted.  Current estimates in southeastern MN project 30% of the tillable acres have not been planted and on many of these acres weeds such as giant ragweed, common lambsquarters and waterhemp are thriving. 

Although weeds are beneficial from an erosion control perspective their rapid growth will make seedbed preparation for planting cover crops very difficult and weed seed production potential will challenge even the best weed management tactics available in 2014.

By Robert Koch, Extension Entomologist

On June 11, 2013, we found soybean aphids on soybean at the Rosemount Research and Outreach Center near Rosemount, MN. Not many beans were out of the ground there, but in the two fields we sampled, we found aphids. We sampled one commercial soybean field at the VC growth stage (unifoliate leaves unfolded) and found 7.5% of plants infested with 1 to 9 aphids on each infested plant. The other field we sampled was a small plot trial, also at the VC growth stage, and had 10% of plants infested with 2 to 3 aphids on each plant.

Volunteer Corn: It's More Than a Weed Control Issue

By Lizabeth Stahl, Extension Educator - Crops

Volunteer corn has become one of the more prevalent weeds in fields across the Midwest. Conditions experienced in 2012, however, have combined to create almost a perfect storm in some fields for potentially high volunteer corn populations in 2013.

By Lizabeth Stahl, Extension Educator - Crops, and Jeff Gunsolus, Extension Agronomist - Weed Science

With very tight windows of opportunity to plant this year, preemergence herbicides may not have been applied as planned.  Application of a residual herbicide prior to planting or emergence of the crop, in both corn and soybean, is a great weed management strategy overall and also a key tool in managing against herbicide resistance.  What are some of our options if soybeans emerged before a preemergence herbicide application was made?   

Black cutworm pheromone trapping network

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By Bruce Potter

IPM Specialist SW MN

The late spring has had one advantage.   Migration of insect pests from the south into Minnesota has been delayed.

The black cutworm, one of the migrant pest species that sporadically causes problems in Minnesota crops, reduced stands in some 2011 and 2012 corn fields.  The females prefer to lay eggs in un-worked fields where areas of winter annual or early spring germinating weeds, common lambsquarters for example, occur.

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