Ramsey County

Howdy!!!

It is raining as we speak and it sure feels and smells good.  Most of the county has received approximately ¾-1 inch of rain to this point.  It is good to know that is can rain to know that we can get something less than a downpour is even more encouraging.  The rain also came very nice with no heavy downpours.  There are still many ranchers out west in need of hay and/or pasture very badly so if you would happen to have or know of any extra hay or pasture, please pass that along to me and I will notify agents in the western part of the state.  The last thing to I would like to mention is cutworms are showing their faces around the area.  I know of at least one field of flowers that has had some significant damage so keep an eye for the cutworm.  

 A NEW CUTWORM SPECIES IN NORTH DAKOTA

        The winter cutworm, Noctua pronuba (Lepidoptera: Noctuidae) was recently reported causing damage on crops in McKenzie County near Alexander this past week.  It has also been reported in Divide, Cass and Richland Counties of North Dakota.  However, entomologists believe that it is distributed across North Dakota.  Noctua pronuba is native to Europe where it is one of the most common Noctuid moths. It was first found in the North America continent in Nova Scotia in 1979. It has spread  rapidly across the northern U.S. Like other Noctuid moths, it is a strong flyer and active at night. It is called the winter cutworm, because it is very cold tolerant and often emerges to feed during warm periods in the winter. It has a wide host range feeding on many agricultural crops (alfalfa, grass hay, potato, sugarbeets, cabbage, carrots, grapes) and ornamental crops.  Although there are no specific threshold developed for winter cutworm, NDSU Extension recommends that you follow the guidelines developed for cutworm management.

      Noctua pronuba is a large cutworm with moths having a 3-inch wingspan and a bright orange-yellow hindwing with a black sub-terminal band (see figure). Caterpillars are up to 2.5-3 inches long when mature.

MAXIMIZING GLYPHOSATE ACTIVITY IN GLYPHOSATE-RESISTANT CROPS

                The goal of all growers should be to maximize glyphosate activity whenever it is applied to glyphosate-resistant crops.  This goal should maximize profitability and weed control, and reduce the risk for herbicide resistance.  Below are the most important management strategies for improving glyphosate activity.  For additional information, consult pages 68 and 69 in the 2008 North Dakota Weed Control Guide.

1.  Apply glyphosate to small (< 4”) annual weeds.

2.  Apply glyphosate to perennial species in the bud to early-flowering stage of development.

3.  Apply the most effective rate for the most difficult to control species in the field.  For many annual species the minimum rate of glyphosate should be 0.75 pounds

acid equivalent/acre (lb ae/A).  Species such as lambsquarters, velvetleaf, wild buckwheat, common ragweed, common mallow, smartweeds, horseweed/mar estail,

and waterhemp can be difficult to control with glyphosate.  Consider using the maximum single-use rate of glyphosate for these species, especially if a reduction in

control has been observed over time.  Rates of glyphosate greater than 0.75 lb ae/A usually  improves control of perennial species, compared to lower rates. 

Multiple glyphosate applications can also improve control of perennial species.

4.  Always add ammonium sulfate (AMS) to glyphosate mixtures.  Ammonium sulfate should be added at a minimum of 4 pounds per 100 gallons of spray mixture

(lbs/100 gal) for most of North Dakota.  Add additional AMS if water hardness is greater than 1600 ppm.

5. Allow at least a 6 hour rainfast period for all glyphosate formulations for maximum activity.  A shorter rainfree period can be acceptible for the most susceptible

species.  Lambsquarters control is usually reduced if the rainfree period is less than 6 hours.

6.  Apply glyphosate during the warmest and most humid weather conditions to maximize activity.

7.  Most glyphosate formulations include nonionic surfactant (NIS) at a high enough concentration for maximum activity.  However, some glyphosate formulations do not include NIS.  For these formulations add a quality NIS product at 0.5 to 1.0 % v/v.  Some weed species, especially lambsquarters, may be more effectively controlled with the addition of NIS at 0.25 %v/v to “loaded” glyphosate formulations.  Know which glyphosate formulations prohibit the use of additional NIS.

8.  Glyphosate activity is influenced by the time of day of the application.  Maximum activity occurs between 10:00 AM and 4:00 PM.  Velvetleaf and common ragweed control may be the most negatively affected by the time of the glyphosate application.

9.  Application of glyphosate in low water volumes improves glyphosate activity.  However, when spraying large weeds and/or dense weed canopies, higher spray volumes usually improves glyphosate activity.

10.  Glyphosate is strongly and irreversibly absorbed to clay particles and organic matter.  Therefore dust of any amount, especially initiated by the wheels of the sprayer, will cause a reduction in glyphosate activity.  The best methods for decreasing this problem are to drive slower and put higher volume nozzles in the boom over the wheels.  These solutions will not completely solve the problem and growers must remember to not apply greater than the single-use rate of glyphosate when using the higher volume nozzles.

11.   When mixing other herbicides with glyphosate, add the most effective adjuvant for that herbicide being added.  This strategy will maximize the activity of the herbicide being added to the glyphosate mixture.  If the alternative herbicide recommends the addition of an oil adjuvant for maximum activity, add only Superb HC or Destiny HC at 0.5 %v/v to the mixture with glyphosate.  The reason for this is that most oil adjuvants antagonize glyphosate activity.

 REVIEW OF WHEAT STEM MAGGOT - WHAT LITTLE WE KNOW

      Last year, there were a lot of complaints from wheat producers about white wheat heads caused by wheat stem maggot. The 2007 NDSU IPM Survey found maggots in 46% of fields surveyed from heading to maturity. White heads were observed from late June to the end of July. The average incidence was 19% white heads with a range from 0% to 50% (see map). Historically, infestation levels have been lower and rarely exceeded 5% in North Dakota.

        Identification:  Wheat stem maggot (Meromyza americana Fitch) is a small fly (about 1/5 inch long) in the family Chloropidae. Wheat stem maggot can be recognized by the following combination of traits: a mostly yellow body with three dorsal black stripes, swollen hind femurs, the head protruding forward between the eyes, and the corner of the mouth forming a nearly right angle (see figure). Wheat stem maggot is the most common chloropid fly infesting wheat in ND, though other chloropid species are found occasionally in wheat.

 ALFALFA HARVEST IS NEARING

        Alfalfa harvest is just around the corner for those lucky enough to have reasonable rainfall or for irrigated producers.  The cool weather has delay the first harvest this year since we typically harvest the last days of May in warm early springs or the first days of June in average years.  Alfalfa at Fargo on dryland is only 13 to 15 inches tall on May 30 when it typically would be 24 to 28 inches tall. 

        Use plant height to determine when to harvest the alfalfa if the weather cooperates.  Plant height affects forage quality of alfalfa more than plant maturity (Table 1).  As the plant grows taller, the relative feed value decreases within each maturity stage due to increasing fiber and lignin laid down to keep the plant erect.  Likewise, as the maturity stage increases, forage quality decreases, but not as fast as with plant height.  For example, alfalfa at the early bud stage decreases in relative feed value from 220 at 16 inches of growth to 156 at 35 inches of growth or 64 units. At 16 inches of height the relative feed value also decreases from 220 to 186 or only 34 units as the maturity increases from early bud to late flower.

        Optimum harvest maturity is when prime hay of 150 to 170 relative feed value can be obtained in the bale.  The values presented in Table 1 are for alfalfa standing in the field.  Forage quality also decreased from harvesting losses, primarily leaf lost.  It is estimated that 20 to 30 units of relative feed value are lost during harvesting with good technique; therefore, harvest must begin at 170 to 180 estimated relative feed value to get prime hay in the bale.  If alfalfa reaches only 16 inches in height, optimum harvest maturity is late flower (defined as the most mature stem with two or more nodes having an open flower), which will likely be the case in drought affected areas this year.  If alfalfa reaches about 28 inches common under irrigation or with good rainfall, the optimum harvest maturity is at the very-late vegetative stage.

        Alfalfa growth has been delayed by the cold weather this year so the plant height is less than previous years, but the maturity stage is less affected by the cold weather.  Forage yield increases with increasing maturity, so delaying harvest to a more advanced maturity will increase forage yield.   Therefore, the optimum harvest maturity will be latter this year than previous years.  Last year the first harvest was taken at medium-bud growth stage at Fargo, which was later than the previous three years when harvest occurred at the very-late vegetative to earliest-bud growth stage in order to harvest prime hay. 

        The PEAQ system described in the previous paragraphs works best on the first harvest when the maturity of stems is more uniform.  The PEAQ system does not work well for the second and third harvest due to the most mature stem occurring much earlier than the average crop.  But the same principal applies, the taller the alfalfa in general, the optimum harvest maturity occurs at an earlier growth stage.       

      The optimum harvest maturity for the second, third, and fourth harvests occurs at more advanced growth stages than the first harvest.  The typical maturity at which we harvest alfalfa at Fargo has been late-bud, 20 to 30% bloom, and regrowth initiating at the bottom of the canopy in the second, third, and fourth harvests, respectively. In a dry year like 2006, the maturity at harvest was late flower (nearly 100%  bloom) for the second and third harvests. 

NDSU Extension Service, North Dakota State University of Agriculture and  Applied Science, and U.S. Department of Agriculture cooperating.  Duane Hauck, Director, Fargo, North Dakota.  Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914.  We offer our programs and facilities to all persons regardless of race, color, national origin, religion, sex, handicap, age.  Vietnam era veterans status, or sexual orientation; and are an equal opportunity employer.

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524 4th Ave NE #5, 2nd Floor Ramsey County Courthouse
Devils Lake  ND  58301
701-662-7027
email - ramsey@ndsuext.nodak.edu

Additional Information:
   NDSU Extension Service Agriculture, Natural Resources