Crop & Pest Report

Accessibility


Crop & Pest Report - All

| Share

2017 Iron-Defeciency Chlorosis Ratings Available (08/17/17)

During the 2017 growing season, Iron-deficiency chlorosis (IDC) has been observed in many soybean fields in North Dakota and northwestern Minnesota.

2017 Iron-Defeciency Chlorosis Ratings Available

During the 2017 growing season, Iron-deficiency chlorosis (IDC) has been observed in many soybean fields in North Dakota and northwestern Minnesota. Symptoms of IDC (see photos) appear if soybean plants are unable to take up enough iron (Fe), even if there is sufficient Fe in the soil. Affected plant tissues are yellow in appearance, with green veins. The symptoms usually show early during the growing season when the plants are in the two to seven trifoliate leaf stages. Soybean plants may grow out of the IDC symptoms and turn green at the end of the vegetative growth stages. Yellowing, browning, and stunting of the plants during the early vegetative stages may result in a reduced soybean yield. Soybean varieties have genetic differences for tolerance to IDC. Variety selection is the best way to combat IDC symptoms in fields with high pH soils, free bicarbonate, and with known chlorosis problems. No soybean variety is immune to chlorosis, but there are large differences between the most tolerant and most susceptible varieties. Selecting a variety with low IDC tolerance for a field with an IDC history, can lead to reduced yield, or even crop failure.

During the 2017 growing season, Iron-deficiency chlorosis (IDC) has been observed in many soybean fields in North Dakota and northwestern Minnesota. Symptoms of IDC (see photos) appear if soybean plants are unable to take up enough iron (Fe), even if there is sufficient Fe in the soil. Affected plant tissues are yellow in appearance, with green veins. The symptoms usually show early during the growing season when the plants are in the two to seven trifoliate leaf stages. Soybean plants may grow out of the IDC symptoms and turn green at the end of the vegetative growth stages. Yellowing, browning, and stunting of the plants during the early vegetative stages may result in a reduced soybean yield. Soybean varieties have genetic differences for tolerance to IDC. Variety selection is the best way to combat IDC symptoms in fields with high pH soils, free bicarbonate, and with known chlorosis problems. No soybean variety is immune to chlorosis, but there are large differences between the most tolerant and most susceptible varieties. Selecting a variety with low IDC tolerance for a field with an IDC history, can lead to reduced yield, or even crop failure.

kandel.1 4

 

Hans Kandel

Extension Agronomist Broadleaf Crops

Ted Helms

NDSU Plant Science, Soybean Breeder


| Share

2nd Generation of Thistle Caterpillars in Soybeans – Scouting Tips (08/17/17)

The 2nd generation of thistle caterpillars are causing feeding injury on soybean leaves (defoliation), mostly low or non-economic populations.

2nd Generation of Thistle Caterpillars in Soybeans – Scouting Tips

The 2nd generation of thistle caterpillars are causing feeding injury on soybean leaves (defoliation), mostly low or non-economic populations. Many calls have come in from north central, central and southeast areas of North Dakota. As we already reported in earlier issues of the Crop & Pest Report, this insect is the larva of the butterfly known as the Painted Lady Butterfly. This butterfly does not overwinter in North Dakota, but migrates from southern states each spring.

These caterpillars are brown to black in color with yellow stripes along each side of the body. They are covered with spiny-hairs that give the caterpillar a prickly appearance. The caterpillars feed on the leaves, webbing them together at the feeding site.

When scouting, consider the age of the caterpillar.knodel.2. If it is a full-grown larva, about 1½ inches long, it is almost done feeding and causing defoliation. So, it probably is not economical to treat this late. Caterpillars feed for 2 to 4 weeks. The next stage is the pupae stage (or chrysalis), a non-feeding stage. The adult butterfly emerges from the chrysalis in 7 to 10 days. Two to three generations are typically seen in North Dakota, depending on how early the painted lady butterfly arrives in North Dakota.

It is easy to overestimate defoliation, especially if you look only at the top leaves of plant and scout only the field edges. Thistle caterpillar prefers the top canopy. For scouting, sample 10 randomly selected plants per site and 4 sampling sites throughout the field (total of 40 leaves). Look at defoliation on the whole plant – top, middle and bottom canopy. Calculate the average defoliation from the 40-leaf sample, if that average is above the threshold, treatment is recommended. Follow this easy sampling procedure for Estimating Insect Defoliation in Soybeans, developed by Dr. McMechan of University of Nebraska (used with permission from Dr. McMechan).

Thresholds for foliage-feeding caterpillars in soybeans are:

  • From bloom (R1) through pod-set (R5), soybean plants can tolerate a 20% defoliation level.
  • As the soybean matures to pod-fill (R6) through harvest (R7), soybean plants can tolerate more defoliation and the threshold increases to a 35% defoliation level

If you don’t have pyrethroid resistant soybean aphids, pyrethroid insecticides will control thistle caterpillars. Observe the Pre-Harvest Interval (PHI) for mature soybeans. Please consult the 2017 ND Field Crop Insect Management Guide.

 knodel.3.

Janet J. Knodel

Extension Entomologist

| Share

Spider Mites in Soybeans in NC ND (08/17/17)

Spider mites are starting to be found in some soybean fields, mainly field edges, in north central ND.

Spider Mites in Soybeans in NC ND

Spider mites are starting to be found in some soybean fields, mainly field edges, in north central ND. Reports have come in from Glenburn, Minot, Underwood and Washburn. The hot dry conditions that this area experienced earlier in the summer stressed soybean, making them more susceptible to mite infestations. Here’s a review of spider mite scouting and thresholds that was printed in an earlier version of the Crop & Pest Report #13.

Mites are small and magnification (10x hand lens) is required to see them. A quick sampling procedure to determine whether mites are present is to hold a piece of white paper below the leaves, then slap or shake the leaves to dislodge the mites. Or, pull plants and examine the underside of the leaves from the bottom of plants upwards. The mites appear as tiny dust specks; however, they will move after being knocked off the leaf. Feeding damage by mites first appears as small yellow spots ("stippling"). As feeding activity increases, leaves become yellow, bronzed or brown, and eventually shed from the plant. Mite webbing may be present on plants as mite numbers balloon on webs to disperse within and between fields. Watch the NDSU Extension YouTube video for more information on scouting for Spider Mites in Soybeans.

Mite Threshold: Deciding whether to treat is difficult. Sample plants at least 100 feet into the field and walk in a “U” pattern, sampling two plants per location at 20 locations. A general action threshold is to treat when heavy stippling on lower leaves occurs with some stippling progressing into middle canopy. Also, when mites are present in middle canopy with scattered colonies in upper canopy and lower leaf yellowing is common. (Source: University of Minnesota, Ostlie & Potter)

Insecticides for soybean aphids and spider mites:knodel.1. If spider mites are a problem along with soybean aphids, the only pyrethroid, IRAC 3A, that will work is bifenthrin(Tundra, Sniper, Brigade, Fanfare, Bifenture, etc.) in soybeans. While other pyrethroids, such as lambda-cyhalothrin (Warrior, Silencer, etc.) will control aphids, they will cause spider mites to flare up and then you may well have to spray again with bifenthrin or an organophosphate (OP) insecticide, IRAC 1B.

Two active ingredients of OP insecticides for control of soybean aphids and spider mites are chlorpyrifos and dimethoate. Dimethoate is weak on soybean aphid control, and has a shorter residual than bifenthrin. We think it’s realistic to expect about a 7 to 10-day residual from bifenthrin (if temperatures are hot, residual duration may be decreased), a 4 to 7 day residual from chlorpyrifos, and a 3 to 5 day residual from dimethoate. The efficacy of an insecticide can be improved significantly with sufficient coverage, >18 GPA of water by ground and 3-5 GPA by air and application at high pressure to penetrate foliage.

Other modes of action for spider mite control only include: IRAC 6 abamectin (Agri-Mek SC) and a miticide IRAC 10B etoxazole (Zeal SC). There also are several combination products with two modes of action that will control soybean aphids and spider mites: Tundra Supreme (bifenthrin + chlorpyrifos), Match-Up (chlorpyrifos + bifenthrin), Brigadier (bifenthrin + imidacloprid), Cobalt Advanced (chlorpyrifos + lambda-cyhalothrin), and Hero (bifenthrin + zeta-cypermethrin). Some combination products contain active ingredients that aggravate mites, such as lambda-cyhalothrin, imidacloprid and zeta-cypermethrin.

It is extremely important to scout and monitor for recurring spider mite populations after spraying. Check your fields five days after treatment and again at regular intervals to make sure your product is holding. If newly hatched spider mites are observed after 5 days, a second treatment may be necessary with a different insecticide mode of action. For example, if you use bifenthrin (pyrethroid, IRAC 3A) for the first application, use a non-pyrethroid product, such as dimethoate or chlorpyrifos (OP, IRAC 1B), for the second application. Look for different IRAC (Insecticide Resistance Action Committee) numbers on labels to indicate different Mode of Action labelling of insecticides. We want to prevent the development of insecticide resistance that has been observed in Minnesota for soybean aphids and spider mites.

Note: Always read and follow the insecticide label. Products are mentioned for illustrative purposes only. Their inclusion does not mean endorsement and their absence does not imply disapproval.


Janet J. Knodel

Extension Entomologist


| Share

Northwest ND (08/17/17)

Information from the Northwest region of North Dakota.

Scattered thunderstorms and some steady rains have been working their way through NW ND for the past week. The middle of last week saw ¼” to ½” fall in many areas and cooler, cloudy weather has persisted since then. This is an unexpected change from the hot, dry conditions that dominated the area in June and July--the past week has felt cool and moist, nothing like the rest of this summer. Last week’s rainfall totals were ½” to 1” for most of McKenzie, Williams, Burke, and Mountrail Counties. The western half to two-thirds of Divide is staying drier and saw less than ½” total. Rains are too late for all but the longest season crops of this year, but will go a long way towards greening up pastures and restoring soil moisture for next year.

The rain has started to interfere with harvest somewhat as crops that were dry and ready to be cut absorb moisture and need to dry down again. Here at the Williston REC, small grains that were not harvested before the rains are undergoing shrinking and swelling. The forecast for the coming week has us returning to more typical August conditions with temperatures in the 80’s and mostly sunny with much diminished chances of rain. If these drier conditions can carry us through the end of the month, harvest progress is likely to move along quickly.

Clair Keene

Area Extension Specialist/Cropping Systems

NDSU Williston Research Extension Center

| Share

Southwest ND (8/17/17)

Information from the Southwest region of North Dakota.

More rain has fallen in parts of the southwest in the past couple of weeks than has fallen prior this growing season. The rain that has fallen has been very scattered, NDAWN observed 0.2 inch on August 15th in Dickinson, but there are reports from just outside of town of more than an inch. From August 1st to August 15th NDAWN observed rainfall in Dickinson to be 1.61 inch, 1.77 inch in Hettinger, and 2.15 inches in Mott. There are still many that need more rain, but over the past week many roadside ditches, pastures, and lawns across the region started greening up. This flush of moisture has also caused some issues. The soil this spring was so dry during planting that many seeds just sat in the soil, many canola fields that are dried down and ready for harvest have a thick carpet of green coming up from seeds that hadn’t germinated until recently. Along with untimely crop growth, this rain has also brought on a wave of weed seedlings. The rain is too late to help yields of most crops. For soybeans, number of pods and number of seeds per pod has already been set, and for sunflowers, head size is already set, but this rain should help with seed size. Corn fields are looking nice and green now, however issues from the extreme heat and dry weather we had really hurt pollination and there is variability within fields in crop height and ear size. For each kernel of corn, one silk needs to be fertilized by a grain of pollen. Extreme heat may desiccate silks. In the picture below, you can see the effects that the heat had on ears of corn here at the Dickinson Research Extension Center. While some ears did fill out nicely others are shortened and irregular.

buetow

The recent rains have kept local producers from working in the fields, but small grain harvest continues across the region. Most yields range from hay bales up to 30 bushels/acre. Herbicide applications are on the mind of many with this fresh flush of weeds. With all of this growth coming up late in the season, be sure to keep post-harvest weed control in mind, especially if planting winter wheat. With proper management, we can avoid the wheat streak mosaic virus issues that we had this spring.

This is our IPM scout Marc Michaelson’s last week before he heads back to Fargo for the school year. I’d like to thank Marc for doing a great job scouting for the issues that affect southwest ND agriculture.

 

Ryan Buetow

Area Extension Specialist/Cropping Systems

NDSU Dickinson Research Extension Center

| Share

South Central/East ND (08/17/17)

Information from the South Central/East region of North Dakota.

The region’s NDAWN stations indicate August 1-15 rainfall ranging from 5.8 inches (Brampton) to 1.8 inches (McHenry). Total rainfall from April 1 to August 15 ranges from 12.8 inches (Cooperstown) to 6.7 inches (Harvey). Estimated daily water use by corn and soybean during the past week (August 9-15) averaged 0.1 inch/day. The August rainfall is valuable for supporting growth of row crops but is hindering small grain harvest and reducing seed quality.

Winter cereal, barley and field pea harvest is essentially complete. Field pea yield is ranging from 30-50 bu/acre with good quality. Barley yield is highly variable (ranging from hayed instead of harvested to 100+ bu/acre) and seed quality average or less. Spring wheat harvest is in progress, with preliminary yield reports highly variable (15 to mid 70 bu/acre) and good protein levels.

Corn planted during the first week in May or earlier generally is in the milk to dough (R3-4) stages. Based on NDAWN growing degree day units accumulated from May 1 planting date to August 15, the region is on par to slightly behind the long-term average. Soybean generally are in the seed formation stages (R5-6); dry bean in the late seed formation (R7) stage; and sunflower in late bloom (R5) to ray flower wilted (R6) stages.

Row Crop tour

Farmers, crop advisers and ag industry representatives are invited to view field research trials and receive production recommendations on corn, soybean and dry edible bean during the NDSU Carrington Research Extension Center Row Crop tour on Thursday, August 24 (registration at 4 p.m. and tour at 4:30 p.m.)

 

Tour topics, presented by NDSU Extension Service crop specialists and Experiment Station scientists, include:

* Corn development update and starter fertilizer research summary

* Soybean variety selection and production update

* Choosing row spacing and planting rate to minimize impact of white mold in soybean

* Dicamba injury in soybean

* Cover crop strategies for soybean and dry bean

* Dry bean variety performance and NDSU breeding program

* Dry bean plant establishment and nutrition

* Optimizing fungicide control of white mold in dry bean

 

Three and a half continuing education credits will be available for certified crop advisers (CCAs). A supper sponsored by associated North Dakota commodity organizations will follow the tour. Additional information about the tour is available at 701-652-2951 or https://www.ag.ndsu.edu/CarringtonREC.

 

Greg Endres

Area Extension Specialist/Cropping Systems

NDSU Carrington Research Extension Center

| Share

Northeast ND (8/17/17)

Information from the Northeast region of North Dakota.

Harvest activities are occurring across the region. Field pea harvest is in full swing. In the north valley and along Hwy 2, wheat and barley crop harvest is underway and picked up momentum over the weekend. Other northern tier counties have predominately barley and canola swathing activities taking place. In the last two weeks, soybean aphid population growth slowed with the cooler temperatures but upticked with the heat early this week. Scout fields after Wednesday’s rainfall to see if the rain decreased soybean aphid populations. IPM thresholds are active through R5 stage, when soybeans located at the top four nodes contain a soybean seed that is 1/8th inch in size. While scouting, you may see soybean leaves with brown spotting from bacterial blight (photo). As this is bacterial, no action is required.

 lubenow.1.

 

 

Lesley Lubenow

Area Extension Specialist/Agronomy

NDSU Langdon Research Extension Center

| Share

A Unique way for Palmer Amaranth to Invade (08/17/17)

Many of you know palmer amaranth arrived as a seed contaminant in pollinator mixes in Minnesota in 2016. There might be a new twist on introduction.

A Unique way for Palmer Amaranth to Invade

Many of you know palmer amaranth arrived as a seed contaminant in pollinator mixes in Minnesota in 2016. There might be a new twist on introduction.

A homeowner reported buying flower seeds from China and potting soil from Walmart. A plant with an unusual flower structure grew from the planted pot. A sample sent to Minnesota Department of Ag was not fit for identification. However, the homeowner had pictures; the pictures showed plants that resembled Palmer amaranth.

Moral of the story, Palmer amaranth may arrive through ornamental seed lots and/or potting soils. This currently is not a confirmed port-of-entry but it is possible, and is something to be vigilant of, especially in areas where spent potting soil might be spread on fields or gardens that can easily transfer weeds and weed seeds to crop fields.

peters.1.

 

Tom Peters

Extension Sugarbeet Agronomist

NDSU & U of MN

| Share

Reporting Dicamba Injury (08/17/17)

In an effort to document the extent of off-site drift of dicamba in ND we ask you to complete the form prepared by the ND DOA (News release and link below).

Reporting Dicamba Injury

In an effort to document the extent of off-site drift of dicamba in ND we ask you to complete the form prepared by the ND DOA (News release and link below). The form is not designed to file a complaint but to indicate extent of injury to susceptible plants and to indicate generally where in the state the injury occurred. We encourage you to complete the form. The information will help us determine the scope of dicamba injury to susceptible crops and plants.

NORTH DAKOTA DEPARTMENT OF AGRICULTURE - Aug. 9, 2017

Farmers encouraged to take survey on possible dicamba damage

BISMARCK – The North Dakota Department of Agriculture (NDDA) is gathering information on plant damage that may have been caused by use of the herbicide dicamba. Dicamba is a selective herbicide used to control broadleaf weeds and woody plants. It has many applications, including lawn care, crop production and range management. Historically, it has been used in pre-plant and pre-harvest applications on soybeans. Recently, new low-volatile formulations have been approved for postemergence use on dicamba-tolerant soybeans.

“Many growers and applicators have expressed concerns regarding potential off-target dicamba applications with resulting crop damage,” Agriculture Commissioner Doug Goehring said. “Those who suspect dicamba damage are encouraged to complete our survey to help us quantify the number of potential reports and acres impacted.”

The survey may be found at: www.nd.gov/ndda/dicamba-survey

Information gathered from the survey will not be used for pesticide enforcement against applicators and no penalties will be issued based on the survey. Those wishing to file a formal pesticide complaint should contact NDDA at 701-328-2231.

 

Rich Zollinger

Extension Weed Specialist

| Share

Soil Sampling Behind the Combine (08/17/17)

Early crops are starting to be harvested and soil sampling may begin at any time. Years ago, NDSU published a ‘sampling date adjustment’, meant to allow for additional nitrate to develop later in the fall should a sampler decide to collect soil before mid-September.

Soil Sampling Behind the Combine

Early crops are starting to be harvested and soil sampling may begin at any time. Years ago, NDSU published a ‘sampling date adjustment’, meant to allow for additional nitrate to develop later in the fall should a sampler decide to collect soil before mid-September. However, on review of the original data on sampling date within North Dakota from August through the following spring, I did not see a trend in nitrate level changes from early dates through spring. Sometimes nitrate levels increased, sometimes they decreased and sometimes they stayed the same. The sampling date adjustment has not been included in any of our fertilizer recommendations for at least ten years.

What is clear, however, is that N recommendations have to be based on soil test nitrate for N responses in our trials in spring wheat, barley, canola, corn, corn, sugar beets and all other N-requiring crops to make any sense.

I would encourage sampling behind the combine first to make sure the job gets done, secondly for the sampler to obtain a more consistent 0-6 inch core for use in determining P, K, pH, organic matter and Zn. Obtaining a consistent 0-6 inch core in worked ground is difficult and usually is done by taking the core over a wheel track, or getting out the pickup and stepping on the intended area to take the core, to make sure the soil just doesn’t flow away from the soil probe when it contacts the surface.

Dave Franzen

NDSU Extension Soil Specialist

701-799-2565

Document Actions

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.