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North Central ND (08/16/18)

Information from the North Central region of North Dakota

The Minot NDAWN station has been replaced with brand new, state of the art equipment and is now equipped with the new inversion sensor technology. Log-on and give it a try.

Pulse and small grain harvest is advancing fairly quickly. Canola has begun to be swathed in many parts of the region, especially from Ward to Renville Counties. Over the past week, my summer crew and I completed the canola survey. Results from that will likely be known later in the year. We will begin working wheat midge survey’s across much of the North Central and Northwestern parts of North Dakota next week and continuing for the next several weeks.

Although delayed from the eastern regions of the state, the late summer flea beetle populations began to rise fairly quickly over the past five days. This generation rarely leads to any economic damage. However, take a note of populations you may see in the field – this may help you plan for the spring season next year.

 

TJ Prochaska

Extension Cropping Systems Specialist

NDSU North Central Research Extension Center

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Does Waterhemp Outcross with Powell Amaranth or Redroot Pigweed? (08/16/18)

Academicians teach agriculturalists to identify pigweed species by the presence or absence of hair on leaves and stem. Redroot and Powell pigweed have very small fine hairs throughout the plant.

Does Waterhemp Outcross with Powell Amaranth or Redroot Pigweed?

Academicians teach agriculturalists to identify pigweed species by the presence or absence of hair on leaves and stem. Redroot and Powell pigweed have very small fine hairs throughout the plant. There are no hairs on waterhemp and stem and leaf surfaces are smooth. Identification based on presence or absence of hairs is qualitative; yes or no, are there hairs on the plant.

There are occasions when Agriculturalists will identify plant samples with a few hairs leading to confusion in identification. Conversation ultimately leads to the question, is hybridization between waterhemp, redroot pigweed and Powell amaranth possible? The implication of this question is important, since glyphosate resistant waterhemp is rapidly advancing north and west from watersheds representing the confluence of the Bois de Sioux and Ottertail rivers and the beginning of the Red River in southern Richland and northern Travers counties in North Dakota and Minnesota. This has initiated speculation as to the potential transfer of this resistance trait among other Amaranthus species, like redroot pigweed and Powell amaranth, common in Minnesota and North Dakota.

Waterhemp plants are either male or female (dioecious). Thus, male plants produce only pollen, while female plants produce only seed. This type of biology leads to cross-pollination, or the fertilization of female plants with pollen from one or more male plants. Cross-pollination can greatly increase the genetic diversity of a population, and with genetic diversity comes a wide range of morphological and biological characteristics. Redroot pigweed and Powell amaranth plants have male and female flowers on the same plant (monoecious).

The literature usually focuses on waterhemp and smooth pigweed, another Amaranth species that is monoecious like Powell amaranth and redroot pigweed. Research has determined that hybridization is possible BUT in only one direction, from smooth pigweed to waterhemp and not from waterhemp to smooth pigweed. Thus, it may be difficult for smooth pigweed (or possibly redroot pigweed or Powell amaranth to acquire herbicide resistance from waterhemp despite the species’ cohabitation. By contrast, waterhemp probably has acquired genetic material from smooth pigweed, which may explain how waterhemp has been able to adapt to fields far removed from its origins in the floodplains along the Mississippi, Missouri and Ohio rivers in southern Illinois, Missouri and northern Tennessee.

 

Tom Peters

 Extension Sugarbeet Agronomist

NDSU & U of MN

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What’s that Grass? (08/16/18)

There is a new player in North Dakota. At least I can’t find reference to it having been here before.

What’s that Grass?

There is a new player in North Dakota. At least I can’t find reference to it having been here before. The name is woolly cupgrass (Eriochloa villosa), also called hairy cupgrass. The plant was identified in wheat fields in Richland and Cass counties as the seed heads reached above the wheat canopy late in the season. Density and distribution in the field suggest the plant has been here for a couple years. The plant is considered by some as invasive because it has the potential to quickly dominate the plant community.

The inflorescence gets purple coloration as the plant and seed mature. A rather unique feature is that two rows of seeds develop along one side of each rachis branch of the inflorescence. The rachis and base of each seed is quite hairy, or woolly, which is noted when seeds are shed. The plant has a hairy ligule, but the most distinguishing feature of the seedling is a prominent crinkle/crimp/tight wave of one leaf margin, especially near the base of the leaf.

The plant can grow in a wide range of soil types and conditions. While a majority of seeds will germinate in the warmer part of spring, woolly cupgrass germination extends well into the summer. This allows establishment after POST herbicides have been applied.

My only experience with this weed was in class and contests when I was in school so we will work with it in the greenhouse this winter to gain better confidence in herbicide options. Not many cereal herbicide labels include this weed, but this could be because it has not been present in typical wheat production areas – until now. Please pay closer attention to fields this fall for presence of this weed and start managing its distribution with harvest scheduling and equipment sanitation.

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Kirk Howatt

Weed Control in Cereals and Oilseeds

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Ergot Being Reported in Wheat (08/16/18)

The wheat harvest is in full swing and reports of ergot have been received from south central, east central and central North Dakota. Below, I will review some of the commonly asked questions with the disease.

Ergot Being Reported in Wheat

The wheat harvest is in full swing and reports of ergot have been received from south central, east central and central North Dakota. Below, I will review some of the commonly asked questions with the disease.

What causes ergot and how does it infect wheat?

Ergot is a fungal disease primarily caused by Claviceps purpurea. The pathogen has a very broad host range with reports of it infecting over 400 grass species including barley, durum, rye, spring wheat, winter wheat, quackgrass, and brome grass. The pathogen survives as hard-bodied fungal structures called sclerotia or ergot bodies. These sclerotia germinate in the spring giving rise to stroma (mushroom-like) that release hundreds of thousands spores during the growing season. Infection in wheat (or other small grains) occurs when spores land on flowers in the early stages of flowering; prior to the visual appearance of the yellow anthers on the center of the head. The spores will land on the stigma of the wheat flower and replace the developing kernel with strands of mycelial (fungal) growth. Successful infection will produce “honeydew” and will be visible prior to flowering (Figure 1). The sugary and sticky honeydew contains asexual spores that are often carried by insects to infect the flowers of other potential host plants/crops. Eventually, the fungal strands will replace the developing wheat kernel, harden and turn into a black-purple sclerotia (Figure 2). The sclerotia can be harvested with the grain or will fall to the soil and overwinter.

What conditions favor ergot?

All literature indicates cool and wet weather during wheat flowering favors sclerotia germination and infection. However, the definition of cool weather is loosely defined in literature. Our experience suggests that ergot is more apparent when temperatures are in the 70’s with ample moisture (dew or rain). Historical accounts of ergot epidemics in North Dakota in the 1920s suggest that prolonged periods of moisture in late June into early July were a major influencer of disease incidence.

Why are there strict thresholds for ergot?

Ergot sclerotia contain toxic alkaloids that can cause harmful effects in both humans in cattle. In humans, the alkaloids will reduce blood flow to limbs resulting in gangrenous symptoms. It also can cause hallucinations and has been linked to the Salem Witchcraft Trials, the weakening of Julius Caesar’s troops and the death of Russian soldiers in the late 1920’s. Livestock fed ergot sclerotia can develop gangrene symptoms of ears, hooves and tails. The alkaloids can also cause abortions and reduce mammary gland development. Therefore, ergoty seed lots should not be fed to livestock.

Management of ergot

  • Crop Rotation – Rotating a broadleaf or corn on a field with ergot will reduce the amount of in-field inoculum. The ergot will survive on the soil surface for about one year, so not providing an available host will reduce the chance of pathogen survival.
  • Tillage – Burying sclerotia at least one-inch into the soil will prevent the stromas (mushrooms) from reaching the soil surface and releasing spores.
  • Mowing or Preventing Grassy Weeds from Heading – Grassy weeds in field margins such as quackgrass or bromegrass will head and flower prior to the small grain crop. Preventing these grasses from heading will reduce the formation of ergot bodies and reduce the risk of spores being carried into small grain fields.
  • Use Ergot Free Seed – The use of ergot free seed will reduce the amount of in-field inoculum.
  • Host Resistance – To our knowledge, there are no small grain varieties with resistance to ergot. However, small grains that have a shorter flowering window are less susceptible. For example, rye tends to be the most susceptible small grain as the flowering process and opening of florets can extend several weeks in field. Observations of ergot in variety trials tend to relate to time of heading and flowering. In other words, varieties that were heading during a conducive time for ergot had a higher incidence than those that escaped the infection window. Other factors that prolong floret openings (cool weather, physiological components or copper deficiency) will increase the risk for ergot as well.
  • Fungicides – Foliar fungicides at heading have not been shown to be effective in managing ergot. Seed treatment fungicides on ergoty seed lots have been shown to delay and disrupt germination of sclerotia. Studies conducted overseas suggest that triazoles (FRAC 3) have reduced viability of sclerotia.
  • Harvesting Strategy – Due to the strict threshold level in wheat (< 0.05% by weight), it is important to scout fields for present of ergot. Often times, ergot incidence will be higher along field margins bordering a road ditch or section line where grassy weed hosts are present. If you notice a higher level along a field edge, keep that grain source separate from the rest of the field.
  • Cleaning an Ergoty Seed Lot – Cleaning using gravity-type or color sorters can help reduce (not eliminate) the amount of ergot sclerotia in a seed lot. Ergot sclerotia tend to be lighter and less dense allowing for the removal of these structures.

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Andrew Friskop

Extension Plant Pathology, Cereal Crops

Joel Ransom

Extension Agronomist for Cereal Crops

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Soybean Cyst Nematode Sampling Program will Begin at the End of the Month (08/16/18)

The North Dakota Soybean Council and NDSU Extension Service are operating the SCN soil testing program again this season.

Soybean Cyst Nematode Sampling Program will Begin at the End of the Month.

The North Dakota Soybean Council and NDSU Extension Service are operating the SCN soil testing program again this season. The program began in 2013, and since its creation, over 3,000 soil samples have been tested for SCN.

In the next week, pre-labeled SCN soil testing bags will be sent to each ND Extension county office in the state. Each grower can pick up as many as three bags, fill the sample bag with soil, provide site information, send the bag to the partner lab (Agvise) and results are mailed to you. The North Dakota Soybean Council will cover SCN laboratory fees on these pre-labeled bags only. This year, 2,000 SCN soil test bags will be available on a first come first serve basis.

In addition, NDSU will use egg levels and geospatial positions of samples to create a map of SCN in North Dakota. This map helps growers know where SCN is occurring and moving. Importantly, NDSU does not have access to any personal information – just the egg level and geospatial data to generate a map.

SCN can cause high levels of yield loss in soybeans, even before above ground symptoms are present. Effective management tools are available and soil sampling to detect SCN is the first step in management. We encourage everyone to make time to sample at the end of the season.

Detailed information about the program, sampling strategy, current distribution maps information about the danger that SCN poses to yield will be provided in the next issue of the NDSU Crop and Pest Report (August 30th).

 

Sam Markell

Extension Plant Pathologist, Broad-leaf Crops

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Water Use in Corn and Late-season Drought Stress (08/16/18)

For much of this growing season conditions were favorable for corn growth and up until recently it looked like we were going to produce a record or near-record crop in North Dakota. Because of the lack of recent rainfall, however, corn is starting to be stressed.

Water Use in Corn and Late-season Drought Stress

For much of this growing season conditions were favorable for corn growth and up until recently it looked like we were going to produce a record or near-record crop in North Dakota. Because of the lack of recent rainfall, however, corn is starting to be stressed. Figure 1 shows the current water deficit levels for the corn crop in various parts of the state. Corn grown in red and orange colored zones very likely already are showing some symptoms of water stress. When water becomes limiting to plants the stomata close, reducing the availability of carbon dioxide within leaf, increasing the temperature of the leaf tissue, reducing photosynthesis, thereby slowing plant growth, though usually hastening crop development (meaning less biomass production and yield because of both a lower rate as well as a shorter duration of growth). The first symptoms of drought stress is leaf curling of the upper leaves. This will be followed by yellowing of lower leaves and firing of leaves along the edges. Green leaves can recover their productivity once stress has been alleviated, but desiccated leaves will not contribute to further growth.

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The impact of drought on corn yield varies considerably depending on its timing, severity and duration. There is little impact of short periods of drought on corn growth during early vegetative stages while the greatest losses occur during pollination (Table 1). Most of the corn crop in North Dakota is probably in the milk to dough stages. Crops in these stages are somewhat less sensitive to drought than crops during pollination. Nevertheless, yield losses can be substantial if drought persists over any length of time. Newer hybrids may be somewhat more productive when stressed than indicated in the table.

Corn is a very water use efficient crop, but it is also a heavy water user. Depending on where in the state, estimated corn crop water use (using NDAWN data) for the past seven days was between 1.2 inches and 1.8 inches. Soils have the capacity to hold up to 10 inches of available moisture in the top four feet, though most will hold less (See Table 2). Unfortunately, most of the stored moisture has been depleted, as noted by the negative water balances exceeding what can be stored in the soil (Figure 1). Obviously additional rainfall is urgently needed if we are to realize the yield potential that was established earlier this growing season.

During grain filling, plants under stress are able to translocate carbohydrates stored in the stem and in leaf tissue to the grain. This helps increase grain yield beyond what might otherwise be expected. Because of the movement of carbohydrates from stalks, It is common for plants stressed during grain filling to have weak stalks. For drought stressed fields, this may be a consideration when deciding when to harvest and which fields to harvest first.

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Joel Ransom

Extension Agronomist for Cereal Crops

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NDSU Extension Cover Crop Field Day (08/16/18)

The North Dakota State University Extension Service will be having a field day on August 28 focusing on the benefits of cover crops in the farming system, including utilization of cover crops as forage.

NDSU Extension Cover Crop Field Day

The North Dakota State University Extension Service will be having a field day on August 28 focusing on the benefits of cover crops in the farming system, including utilization of cover crops as forage. The full day of educational sessions and tours will be held at the Coteau des Prairies Lodge (near Rutland), 9953 141st Ave. SE in Havana, beginning at 9:00 a.m. and ending at 3:00 p.m.

Participants will visit the field research and demonstration plots on a nearby farm. Field stops will highlight nutrient release from previous cover crop in this year’s corn, cover crop selection on land with residual herbicide and weed control options, bio-strip till with radish following wheat harvest, and practices to effectively manage soil moisture.

Cover crop use is becoming more common in the Dakotas, but cover crop incorporation such as winter camelina and rye in corn and soybean in North Dakota is still a newer concept. Other cover crops with potential in the farming systems are also being tested at various locations in North Dakota.

Participating in this educational event field will provide growers an opportunity to learn about the research near Rutland and to see how cover crops have a place on a working farm when grown on a large-field scale. Interacting with other participants is also a great way to gain insights in the utilization of cover crops and building the soil quality.

The afternoon educational sessions will include information on alternative uses for cover crops including forage opportunities and fine tuning cover crop management in soybean and corn.

Lunch is provided, and registration is highly encouraged on the NDSU Soil Health webpage, under the events tab, NDSU.edu/soilhealth.

This field day is part of the outreach effort associated with a grant the U.S. Department of Agriculture (NIFA) awarded to North Dakota Agricultural Experiment Station scientists. The grant is being used to study how cover crops can increase the resilience and productivity of crops such as corn and soybeans, improve soil health, and land use efficiency. More information about the research and preliminary results can be accessed at the project’s web site at https://www.cropsyscap.org/

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Abbey Wick

 NDSU Extension Soil Health Specialist

 

 Hans Kandel

Extension Agronomist Broadleaf Crops

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Wheat Stem Sawfly in NC ND (08/16/18)

I've had several other calls on wheat lodging from wheat stem sawfly in Berthold area in Ward County (Andrew Green, NDSU Wheat breeder), Mohall area in Renville County and Souris area in Bottineau County.

Wheat Stem Sawfly in NC ND

I've had several other calls on wheat lodging from wheat stem sawfly in Berthold area in Ward County (Andrew Green, NDSU Wheat breeder), Mohall area in Renville County and Souris area in Bottineau County. The dry conditions in these areas probably aggravated the wheat stem sawfly problem. The best strategy is to swath wheat if more than 15% of stems are infested with wheat stem sawfly larvae. Producers should swath sawfly-infested wheat as soon as kernel moisture drops below 40% to save infested stems before they lodge. Lodging occurs at 30-35% moisture in infested sawfly stems. This requires field surveys to determine infestation levels. Infested stems have a reddish-brown spot below the second or third node. Examine 50 consecutive stems in a drill row from at least two sites (one near the field margin, another near the center). Determine the percent of stems infested at each site. If producers decide to swath grain, use a high swathing height to conserve the parasitoids that attack wheat stem sawfly. Research from Montana State University has shown that taller residue (at least the lower ⅓ of the plant) is better for conserving the parasitoids.

If 10 to 15% of the crop was cut by sawfly during the current field season, a solid-stemmed variety of wheat is recommended for the upcoming field season. I would recommend a high-yielding, solid-stemmed (sawfly resistant) variety like Mott, or one of the Canadian or Montana varieties (see NDSU Extension Integrated Pest Management of Wheat Stem Sawfly in ND for listing of solid-stemmed varieties).

Insecticides DO NOT work for control of adults and are a waste of time and money. Insecticides actually make the situation worst since broad-spectrum insecticides kill the beneficial wasps that attack and decrease populations of wheat stem sawfly. These parasitic wasps have a moderate parasitism rate, >30% in ND.

Crop rotation to non-host crops (oats, flax, sunflower, canola, pulse crops, soybeans, legumes, and to a lesser extent barley, rye) will break the insect’s life cycle and help reduce populations of wheat stem sawfly.

 

Janet J. Knodel

Extension Entomologist

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Red Sunflower Seed Weevil High (08/16/18)

Continue to scout for red sunflower seed weevil.

Red Sunflower Seed Weevil High

Continue to scout for red sunflower seed weevil. The majority of sunflowers are blooming, >90% (Source: USDA NASS North Dakota Crop, Livestock & Weather Report - August 13, 2018). Hot weather has pushed many sunflower pass the susceptible crop stage, R5.7 (70% of the face of sunflower head with florets), for egg laying by female red sunflower seed weevils. Hot spots for seed weevil are in southwestern, north central and south central ND (Source: ND IPM Survey Program). See the past issue in Crop & Pest Report from July 26, 2018 for scouting/threshold information.

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Janet J. Knodel

Extension Entomologist

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Soybean Aphids Still Low (08/16/18)

Hot weather has decreased the risk of economic soybean aphid infestations, and soybeans are maturing quickly.

Soybean Aphids Still Low

Hot weather has decreased the risk of economic soybean aphid infestations, and soybeans are maturing quickly. The crop stages of soybean ranged from R4 (full pod set) through R6 (full seed set) crop stages, so in some areas we are at the R6 (full seed set) crop stage where there is minimum impact on yield from soybean aphid feeding injury. It looks like most soybean fields escaped damage from soybean aphids in ND! Good news for soybean producers.

Continue to scout for soybean aphid populations, especially in any late-planted soybeans.

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Janet J. Knodel

Extension Entomologist

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This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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