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Cover Crop Exchange (8/03/17)

At one of Dr. Wick’s Soil Health Café Gatherings this past winter, some of the attendees talked over the use of cover crops for livestock and at least in eastern North Dakota during years of excess water, cover crops were helpful in reducing soil water, maintaining soil cover to prevent wind erosion and perhaps serving as fall cattle feed.

Cover Crop Exchange

At one of Dr. Wick’s Soil Health Café Gatherings this past winter, some of the attendees talked over the use of cover crops for livestock and at least in eastern North Dakota during years of excess water, cover crops were helpful in reducing soil water, maintaining soil cover to prevent wind erosion and perhaps serving as fall cattle feed. Some of the producers had no livestock and thus asked if there was a ‘cover crop exchange’, similar to the ‘hay exchange’ that exists in North Dakota. The central/western ND drought prompted me to ask within NDSU if there was a cover crop exchange and at the time, the answer was no; but they would be willing to add cover crop to the exchange if we thought it would be helpful. So with the help of NDSU’s Roger Egeberg, the ‘Cover Crop Exchange’ is now available in the NDSU-Feed list website https://www.ag.ndsu.edu/feedlist .

To participate, farmers that have cover crop and farmers interested in grazing their stock in the cover crop should go to the Feedlist Entry Form, found at https://www.ag.ndsu.edu/info/fl_new

This form should be filled out whether cover crop is available or cover crop is wanted. Click on the ‘create entry’ button when the form is complete and the administrators of the website will take care of the rest. When cover crop availability and need meet, the two parties can visit regarding fencing, water availability and anything else relevant to the transaction.

 

Dave Franzen

NDSU Extension Soil Specialist

701-799-2565

 

Abbey Wick

NDSU Extension Soil Health Specialist

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Reports of Goss’ Leaf Blight (Wilt) on Corn (8/03/17)

Areas of the state have received high winds, hail and rain, thus elevating the risk for the development of Goss’ wilt in corn.

Reports of Goss’ Leaf Blight (Wilt) on Corn

Areas of the state have received high winds, hail and rain, thus elevating the risk for the development of Goss’ wilt in corn. This week, a Goss’ wilt sample from Foster County was received by the NDSU Plant Diagnostic Lab and field reports of the disease have been received from agronomists in Cass County. There are no recommended in-season management tools for this disease, however identification will help shape future management decisions. This disease is best managed using resistant hybrids, crop rotation and corn residue management. The greatest amount of yield loss attributed to this disease occurs when a susceptible hybrid is infected early in the growing season (vegetative leaf stages). Late season infections occurring after tasseling and reproductive stages will often result in minimal losses.

When scouting corn fields, the first noticeable symptom of Goss’ wilt is the premature death of leaf tips or an entire plant. This can be caused by several disorders such as nutrient stress and drought stress. Tip dieback caused by Goss’ wilt will have irregular water soaked (greasy) lesions that extend towards the stem and with diagnostic freckeles within the lesion (Figure 1). Also, Goss’ wilt is often first noticed in ‘pockets’ in a field.

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Andrew Friskop

Extension Plant Pathology, Cereal Crops

 

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Cercospora Leaf Spot Control in Sugarbeet (8/03/17)

The fungal pathogen, Cercospora beticola causes Cercospora leaf spot (CLS) in sugarbeet. CLS is the most destructive foliar disease of sugarbeet in North Dakota and Minnesota.

Cercospora Leaf Spot Control in Sugarbeet

Causal Agent

The fungal pathogen, Cercospora beticola causes Cercospora leaf spot (CLS) in sugarbeet. CLS is the most destructive foliar disease of sugarbeet in North Dakota and Minnesota. Severe CLS in 2016 has resulted in a high overwintering population for the 2017 crop.

Current level of Cercospora leaf spot and fungicide control

CLS is currently present in all factory districts in North Dakota and Minnesota. The disease is currently most severe in southern Minnesota where near weekly rainfall event has made conditions favorable for infection and disease development. Early planting coupled with favorable environmental conditions resulted in good crop growth and early row closure. In many areas, growers have been successful at providing adequate CLS control by starting fungicide applications at disease onset or at first symptoms and making timely applications.

In research trails at Foxhome, MN, disease is starting to become severe in the non-treated check plots. Growers will need to continue using effective fungicide mixtures, monitor fields for disease control, and try to avoid extending spray intervals especially in areas that receive more rainfall. Cercospora population tend to increase significantly in August and cause severe defoliation if not effectively controlled. If the weather is warm (higher than 77°F in the day and 60°F at night) and wet in August, growers may need two to three fungicide applications involving mixtures to effectively control CLS in August of 2017. Please contact your agriculturists, consultants, County Agents or me if you need advice on controlling CLS.

Mohamed Khan

Extension Sugarbeet Specialist

NDSU & U of MN

701-231-8596

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Late Blight Update (8/03/17)

Late blight has been confirmed in a commercial potato field in Pembina County and Nelson County, ND. The genotype from Pembina County is US23.

Late Blight Update

Late blight has been confirmed in a commercial potato field in Pembina County and Nelson County, ND. The genotype from Pembina County is US23. Late blight has been reported in other areas, but not confirmed. Home gardens can be a source of late blight because tomatoes and potatoes are generally not treated with fungicide. Tomatoes are susceptible to the US23 genotype. Because of the widespread findings of late blight, we recommend that all potato fields in northeastern ND should be thoroughly scouted for the presence of late blight. Growers in areas where late blight is present should apply a specialty fungicide with strong activity against late blight, such as Orondis, Revus Top, Ranman, Omega or Gavel.

All areas bordering the Red River Valley north of Interstate 94 have exceeded the late blight threshold value of 15. This indicates that conditions have been favorable for late blight infection if inoculum is present. Growers in this area should be scouting fields and applying fungicides, concentrating on areas of the field that stay wet longer such as along tree lines and low areas where water accumulates.

Please send suspect late blight samples to NDSU so we can identify genotypes and monitor the spread and location of late blight. Remember that late blight is a community disease and to notify your neighbors if late blight is found. Please see the NDSU Extension bulletin Late Blight in Potato for pictures and more information on late blight.

 


Andy Robinson

NDSU/U of M Extension Potato Agronomist

 

Gary Secor

NDSU, Plant Pathologist

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Cover Crops Tour (8/03/17)

A daylong educational program has been set for Tuesday August 15th, starting with registration at 8:30 a.m. at the Coteau des Prairies Lodge (9953 141 Avenue SE), in Havana, ND.

Cover Crops Tour

Incorporating Cover Crops, Perennials and Oilseed Cash Crops

A daylong educational program has been set for Tuesday August 15th, starting with registration at 8:30 a.m. at the Coteau des Prairies Lodge (9953 141 Avenue SE), in Havana, ND. The event will include educational sessions at the lodge about alfalfa-corn intercropping, camelina and pennycress as cash cover crops, and how to include cover crops into the rotation. Participants will also visit the field research and demonstration plots on the nearby farm. Stops include cover crops interseeded into soybean and corn and a fertility study, researching the effects of cover crops on soil health.

The event is part of the outreach effort associated with the USDA/NIFA grant “A novel management approach to increase productivity, resilience and long-term sustainability in cropping systems in the Midwest”. Additional Information on the project can be found at CropSys-Cap. Use of cover crops is common in the Corn Belt, but incorporating cover crops such as camelina and rye in corn and soybean in North Dakota is still a new concept and needs research. Participating in this field day Interacting with other participants is also a great way to gain insights in improved soil health practices.

The event will start at 9:15 a.m. and will finish at 3:30 p.m. Lunch is provided, however signup is required. Registration will be capped at 150 participants.

You can find the agenda and the registration link on the NDSU Soil Health Webpage. https://www.ndsu.edu/soilhealth/, register as soon as possible.

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Hans Kandel

Extension Agronomist Broadleaf Crops

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Red Sunflower Seed Weevil High (8/03/17)

Field reports indicate that populations of red sunflower seed weevil are high, average of 20-30 weevils per head in the southwest and south central parts of North Dakota.

Red Sunflower Seed Weevil High

Field reports indicate that populations of red sunflower seed weevil are high, average of 20-30 weevils per head in the southwest and south central parts of North Dakota. This is way above the economic threshold levels of 5-6 weevils per head for oilseed sunflowers and only 1 weevil per head for confection sunflowers. Continue to scout for red sunflower seed weevils, and banded sunflower moth in sunflowers until fields reach the R5.7 crop stage (70% of the head area has completed or is flowering). A plant that has reached 70 percent pollen shed has very few seeds that are still at a stage of development suitable for red sunflower seed weevil egg laying. Therefore, when most plants are at the 70 percent pollen shed stage the field effectively is no longer susceptible to further damage.

Remember to avoid sampling just sunflower fields near edges since weevils often concentrated in field edges. When sampling, choose four sampling sites with one site on each side of the field. The sampling sites should be at least 75 feet in from the edge of the field. Count the number of weevils on three plants at each site for a total of 12 plants. The key to accurate estimation of weevil populations in the field is representative sampling. Sunflower heads for weevil counts must be randomly selected without regard to plant stage.

Insecticide Timing: Sunflower plant stage is used to time insecticide treatment. Both bloom and flowering describe the sunflower plant when yellow ray petals are showing and pollen is being shed. It is important to distinguish between the percentages of the field in bloom from the percentage of individual plants in bloom. A field with 50 percent of the plants in bloom indicates that half of the plants are shedding pollen and the other half of the plants are in the bud stage. However, the individual plants in bloom will probably not all be at the same stage of bloom. Some plants may have just started to shed pollen and others may be at the end of pollen shed. A plant in the 40 percent bloom stage would have 40 percent of the head shedding pollen (R5.4). This would be a ring of opened florets comprising about 25 percent of the head radius. The remaining 60 percent of the florets would be unopened.

The ideal plant stage to treat is when most plants in the field are at 40 percent pollen shed (R5.4). However, we recommend that treatment be considered when more than half of the plants in the field are just beginning to show yellow ray petals (R5.0) to 30 percent of the head shedding pollen (R5.3) and the rest of the plants in the field are still in the bud stage. This difference between the ideal plant stage (R5.4) to treat and the earlier plant stage (just beginning pollen shed) is based, in part, on the fact that aerial applicators -- because of a busy schedule or adverse weather -- will not always be available to spray at the ideal stage of sunflower development. Considering treatment at the early bloom stage should allow growers a sufficient cushion of time to have their fields treated. Growers must be aware, however, that if weevil populations are high and/or spraying is done too early, a reinfestation may occur and a second insecticide application may be necessary.

Although insecticides applied to sunflower at the bud stage will kill weevils, treatments at that stage are not economical or effective because (1) seeds have not developed to a stage suitable for oviposition, (2) eggs within the weevil are not mature, and (3) adult weevil emergence is still continuing. Sunflower normally reaches the bud stage in late July at which time only about 30 percent of the weevils in the soil have pupated and emerged. Most weevils emerge from the soil by the first week of August. If growers were to spray bud stage sunflower in mid to late July, a second spray may be necessary as more weevils continue to emerge.

Janet J. Knodel

Extension Entomologist


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Corn Rootworms Emerging (8/03/17)

Corn rootworm adults were reported emerging the last two weeks in southeastern and south central North Dakota.

Corn Rootworms Emerging

 Corn rootworm adults were reported emerging the last two weeks in southeastern and south central North Dakota. The northern corn rootworm usually emerges first; the western corn rootworm emerges one to two weeks later. Adult emergence typically is completed by mid-October.   

The potential for economic corn rootworm larval damage for the following year can be estimated by counting the number of rootworm adults on corn plants. Start scouting three weeks after pollination and continue once per week until silks are dry and brown.

Randomly select 10 nonconsecutive plants in 10 representative locations throughout the field for a total of 100 plants. During corn ear inspection, carefully cover the silk with one of your hands, then count the number of adults present by slowly allowing your hand to open. Gently disturb silks near the ear tip to dislodge and force beetles to exit.

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Also check the stalk, upper and lower leaves, leaf axils and tassel for corn rootworm beetles. Pull leaves down when inspecting the leaf axils because adults often hide in leaf axils. Count and record the number of adults of each species, then estimate the average number of adults per plant by species.

  • Threshold for first-year corn: Management in the following year’s corn crop is recommended if you find an average of two or more adults per plant for northern corn rootworm or one adult per plant for western corn rootworm.
  • Threshold for continuous corn: Management in the following year’s corn is recommended if you find an average of three or more adults per plant for northern corn rootworm or 1.5 adults per plant for western corn rootworm.

Please see the NDSU Extension Service publication “Integrated Pest Management of Corn Rootworms in North Dakota” E1852 for more information.

 

Veronica Calles-Torrez                                           Janet J. Knodel                                          Mark Boetel

Graduate Student                                                    Extension Entomologist                         Research & Extension Entomologist

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Pyrethroid Resistant Soybean Aphids: What are your Control Options?(8/03/17)

We have received a number of reports of pyrethroid insecticide failures for soybean aphid management from northwest and central Minnesota, and northeastern North Dakota this year.

Pyrethroid Resistant Soybean Aphids: What are your Control Options?

                We have received a number of reports of pyrethroid insecticide failures for soybean aphid management from northwest and central Minnesota, and northeastern North Dakota this year. However, many areas of Minnesota and North Dakota still have low, non-yield threatening aphid numbers and scouting should continue to determine when to apply insecticides.

In this article, we review the insecticide groups used for soybean aphid control (Table 1) and discuss the potential role of and challenges associated with insecticide mixtures.

We are all familiar with the multistate, researched-based economic threshold of 250 aphids/plant for determining when to apply insecticides for soybean aphid. Waiting until this economic threshold to apply insecticides is KEY for ensuring continued efficacy of current insecticides for soybean aphid. Using the soybean aphid economic threshold for deciding when to apply insecticides will:

1) Prevent unnecessary insecticide resistance selection pressure;

2) Save time by reducing the odds of a field needing a second treatment;

3) Mitigate secondary pest problems like spider mites; and perhaps most importantly

4) Reduce production expenses.

Poor insecticide resistance management of a mobile insect like soybean aphid affects not just your farm, but other farmers as well.

                Farmers who experience aphid populations above the threshold, and those who sprayed too earlier and may need to re-treat, face some serious questions. What options do soybean growers have in light of increasing aphid populations and populations that are potentially resistant to a pyrethroid insecticides? Here are some recommendations to improve pest management of soybean aphids.

When applying any insecticide for soybean aphid, spray coverage and canopy penetration are critical.

  • Do not use reduced insecticide rates.
  • Use appropriate spray pressure and spray nozzles (for example. do not use large droplet Engenia or Xtendimax approved nozzles) to treat aphids.
  • Do not skimp on water. At least 15-20 GPA via ground and 3-5 GPA via air.
  • Insecticide applications during windy conditions, temperature inversions, or very hot weather could reduce control.
  • Check insecticide performance 3-5 days after application.

 

Do NOT retreat a field with the same insecticide group for consecutive applications!

  • If it didn’t work the first time why would it work the second time?
  • If it did work the first time, it might not work the second time.

Premixes and tank mixes with reduced rates of one or more insecticides should be avoided.

INSECTICIDE GROUPS (TYPES)

Pyrethroids (Group 3): In light of recent pyrethroid performance issues, it is not advised to apply an insecticide containing only a pyrethroid insecticide(s) in most areas of Minnesota and in northeastern North Dakota. Insecticide group numbers can be found on the label.

  • These broad-spectrum insecticides have been widely used for soybean aphid control.
  • Insecticides in this group are not equally effective on soybean aphid.
  • Resistance levels may vary among pyrethroid products and soybean aphid populations.
  • Potential for 7-10 days residual but new growth not protected.
  • If you do use a pyrethroid on soybean aphids use a high labeled rate.
  • Among the pyrethroids, only bifenthrin is labeled for control of spider mites.
  • These insecticides are toxic to beneficial insects and bees.

If a pyrethroid insecticide application may not work well, which insecticides should be considered?

Organophosphates (Group 1): for example, chlorpyrifos (Lorsban and generics)

This is one preferred option for 1st applications in a field or when retreating a field that was previously treated with a pyrethroid insecticide.

  • Still very effective against soybean aphid populations in previous years.
  • This insecticide does not have a long residual and volatilization is increased in warm weather. Soybean aphids can re-colonization chlorpyrifos treated fields within a few days.
  • This group provides broad-spectrum control of pests
  • Dimethoate, another organophosphate insecticide labeled for soybean aphid, has provided variable and sometimes suboptimal control of soybean aphid in efficacy trials in Minnesota and North Dakota when used alone.
  • Chlorpyrifos and dimethoate have shown good activity on Minnesota populations of two-spotted spider mite. Some populations of spider southwest Minnesota have shown resistance to chlorpyrifos.
  • These insecticides are toxic to beneficial insects and bees.

 

Neonicitinoids (Group 4A): for example, Belay, Admire Pro, Alias

  • These insecticides are absorbed and translocated short distances within the plant. They may be moved upward for a leaf or two.
  • At high rates, this insecticide group can provide residual activity, but not more than 2-3 weeks.
  • Provide fairly broad-spectrum control for chewing and sucking pests.
  • These insecticides are toxic to some beneficial insects and bees.

 

Butenolides (Group 4D): Sivanto

  • This is a recently labeled chemistry for soybean aphid. We do not have a large data set for this insecticide on soybean aphid. Data from Minnesota in 2015 showed moderate control of very large soybean aphid populations.
  • Like the related neonicotinoids, this chemistry is translocated short distances within the plant.
  • This insecticide sub-group is only effective on some species of sucking insects.
  • This chemical has relatively low toxicity on honeybees.
  • This is an expensive insecticide ($17.85 to $35.70 per acre for the insecticide alone), so cost is an issue.

 INSECTICIDE MIXES: While we do not generally recommend premixes or tank mixes of insecticides. Such mixtures may be necessary when products with single insecticide groups have already been applied to a field.
Pyrethroid Premixes (such as Hero)

  • Mixtures of multiple pyrethroids do not make sense when treating a soybean aphid population that is already suspected to be resistant to pyrethroids. All pyrethroid insecticides are in the same insecticide group (Group 3A).

Neonicotinoid Premixes (such as Endigo, Leverage)

These premixes would be a preferred option following a chlorpyrifos application

  • In University research trials, these mixes have provided control of aphids. One of these (Endigo) has been tested on and been shown to provide control of pyrethroid-resistant soybean aphid populations.
  • Based on the lower levels of control observed in northwest and central Minnesota this year, the neonicitinoid portion would need to do most of the control, increasing resistance selection pressure on that group and perhaps control.
  • Watch for increasing spider mite populations after a foliar neonicitinoid application has been applied to field.
  • If you used an insecticide seed treatment, you have already made one neonicitinoid application to the field.

 

Organophosphate Premixes (such as those with chlorpyrifos - Cobalt, Tundra Supreme, and Stallion)

  • Our trials have shown effectiveness of chlorpyrifos-containing mixtures (Cobalt) against soybean aphid in recent years.
  • In trials in southwest Minnesota in 2016, pyrethroid control appeared to be improved with the addition of dimethoate.
  • After the application of an organophosphate-pyrethroid premix, the field is protected for up to a few days by the organophosphate; however, the longer resisdual activity of the pyrethroid will not be effective on surviving or incoming aphids that are resistant to pyrethroids.

For those wanting to mix products, be advised that there may be compatibility issues when tank-mixing insecticides.

  • Test any potential tank mix for compatibility first.

                When choosing insecticides, consider the abundance of yield threatening insect pests first. For example, do not base an insecticide choice on non-threatening levels of a secondary pest, such as spider mites. However, if dry conditions persist, spider mites to quickly become a real concern that will further complicate insecticide selection.

  • Two miticides, Zeal SC and Agri-mek, are now labeled for spider mite control in soybean.

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Bruce Potter (Extension IPM Specialist, UMN), Robert Koch (Extension Entomologist, UMN), Phil Glogoza (Extension Educator – Crops, UMN), Ian MacRae (Extension Entomologist, UMN), and Janet Knodel (Extension Entomologist, NDSU)

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Weather Forecast (08/03/17)

The August 3 through August 9, 2017 Weather Summary/Outlook

Temperatures were one to four degrees above average at most North Dakota Agricultural Weather Network (NDAWN) stations in the past week. The one notable exeption was in southeastern North Dakota where temperatures average near or slightly below normal. A significant cool down that began yesterday will continue with the first half of August projected to record below average temperatures.

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There were two main rain events in the past week with both associated with a small cluster of thunderstorms. One occurred last Thursday morning (July 27) from northwestern North Dakota to the south central part of the state. The other was a smaller series of thunderstorms on Monday evening (July 31) that started in the northern Red River Valley and slowly moved southward where it eventually weakened and faded away. Otherwise, much of the week was dry with the central portion of North Dakota recording little to no rainfall. The rain that fell yesterday into this morning (Thursday) is not included in the graphic below.

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The rain that did fall yesterday and that is still likely lingering in some portions of far eastern North Dakota and northwestern Minnesota this morning was associated with a secondary push of cooler air from northern Canada. A weaker cold front moved through the region on Monday night, but a more significant cold front came through in the past 24 hours and is associated with a major weather pattern shift over North America. A large “bubble” of warm air (ridge of high pressure) along the west coast of the United States has developed and is expected to last at least 10 days and possibly longer than that, meaning well below average temperatures on most days for the first half of August. The cooler pattern does not necessarily mean a change in the frequency of rain events, as outside of what fell in the past 36 hours, most days will be dry and what rain does fall is expected to be widely scattered during the next 7 to 10 days.


With temperatures anticipated to be well below average for the time of year during this forecast period, the projected growing degree days (GDDs) will be significantly lower than what was recorded in the past week. The projected GDDs, base 32°, 44° and 50  for the period August 3 through August 9 is presented below.

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With the cool air in place, plus the rainfall from Wednesday and Wednesday night adding to the availability of low level moisture, the number of hours with relative humidity (RH) above 85% is projected to very high in the next seven days. With minimums in the 40s on some mornings you should expected heavy dew on some days that will linger on plants beyond sunrise increasing the risk for plant diseases.

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Using May 10, 2017 as an average planting date, the number of corn growing degree days (Base 50°) accumulated through August 1 is depicted below. The exact numbers based on your actual planting date(s) can be found here: https://ndawn.ndsu.nodak.edu/corn-growing-degree-days.html

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Using a planting date of May 1, 2017, the number of wheat growing degree days (Base 32°) accumulated through August 1 is presented below. The exact numbers based on your actual planting date(s) can be found here: https://ndawn.ndsu.nodak.edu/wheat-growing-degree-days.html

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Daryl Ritchison

Meteorologist

Interim Director of the North Dakota Agricultural Weather Network

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Southwest ND (8/03/17)

Information from the Southwest region of North Dakota.

Scattered rain has hit parts of the region over the past week. NDAWN observed 0.29 inch of rain in Dickinson on August 1st. More rain would be welcomed, even with producers working on harvesting small grains and lentils. Harvested yields have been low as expected. There is a haze in the sky, most likely from fires in Canada and Montana. With the hot and dry weather be sure that you are prepared in case of a fire. Most sunflowers in the region are now in the early stage of flowering. Canola is continuing to ripen, some canola fields have dried down with others still very green. All of the canola fields I have seen are very thin and short, lodging is not an issue this year.

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Ryan Buetow

Area Extension Specialist/Cropping Systems

NDSU Dickinson Research Extension Center

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