Cutworms become active when soil temperatures are above 40F. With the statewide cool soil temperatures in May, cutworms will develop slower and this could result in a prolonged feeding period this year. Cutworms injury plants by chewing and/or cutting the plant in the early stages of crop development (seedling stage = most susceptible). Generally, cutworms destroy more of the plant then they eat. Their numbers vary greatly from year to year and when numerous may destroy 50-75% of a crop! Cutworms feed at night and hide in soil during the day. Since there are early and late season cutworms, feeding activity usually extends from May through the end of June.

The key to successful cutworm control is early detection and knowing your plant population. Field scouts should look for cut or wilted plants, and dig around underneath freshly cut plants to find cutworms in the soil. A flashlight at night can also be used to find the night feeding cutworms. If the plant population is below recommended, few or no plants can be lost to cutworm feeding. The greater the plant population the more damage can be tolerated without economic yield loss. When spraying insecticides for cutworm control, applications should be made in the evening when cutworms are actively feeding. Wet soil conditions will also improve insecticide efficacy, as cutworm feed near the soil surface in these conditions. Treatment threshold vary depending on the field crop:

Canola – 1 per square foot

Small grains – 4 to 5 cutworms per square foot

Corn – 3 to 6% of the plants cut and small larvae less than 1-inch present

Soybeans / Dry beans – 1 or more larvae per three feet of row or 20% of plants cut

Sunflower – 1 per square foot or 25-30% of plants cut

Alfalfa – 4 to 5 or more per square foot (new or thin stands – only 2/sq ft)

Lentils – 2 to 3 cutworms per square meter (Canada)

Peas – 2 to 3 cutworms per square meter (Canada)

Please see “2008 North Dakota Field Crop Insect Management Guide” for list of insecticides available on different field crops.

APPLICATION OF AMMONIA TO DRY SOILS

Dave Franzen

NDSU Extension Soil Specialist

701-231-8884

david.franzen@ndsu.edu

 Many soils in our drier areas are the consistency of ash. However, even these soils contain a thin water film around soil particles. I would still consider application of anhydrous on these soils, however, the ammonia will move more initially in these soils laterally and vertically than normal. Application down to 6 inches would be my best recommendation. Shallow applications (3 inches or more shallow) will lose at least 10% of product soon after application. Application using larger hoses/tubes (½ inch instead of 3/8) may reduce the ammonia expansion initially. Make sure that there is at least 3 inch lateral distance between seed and ammonia application point. If the only ammonia application method alternative is shallow application, considering the lost efficiency, perhaps urea application would be a better choice in these soils if it is applied beneath the soil surface.

WINTER INJURY ON EVERGREEN TREES

 Joe Zeleznik

Extension Forester

joseph.zeleznik@ndsu.edu

Winter injury on evergreen trees has been reported in many areas of the state this spring (Fig. 1 and 2). It is most often seen on Colorado spruce and on certain pines, though junipers and arborvitaes are sometimes affected. The term “winter injury” actually encompasses a variety of needle-discoloration problems. Whole needles or portions of needles often turn brown or an orange-rust color, though spruce needles may get a purplish caste on their way to becoming rust-colored. Spruce trees are sometimes mistakenly diagnosed with Rhizosphaera needlecast, based on the needle coloration. The cause that is most-often cited is having warm, sunny and windy winter days that allow the trees to begin photosynthesis and transpiration, while the ground is still frozen. The trees lose moisture from their needles and are unable to replace it. Other potential causes include dehardening of needle tissue during warm winter days followed by plummeting temperatures. In those cases, trees can’t re-harden their tissues and needle damage results. Trees that have been stressed by insects, diseases or drought may be more susceptible to injury. Recently transplanted trees, as well those growing in areas without snow cover are also prone to damage.

What can be done about winter injury? At this point, not a whole lot. The injury has already occurred.

However, damage is usually (but not always) just aesthetic. If the buds are unharmed, then the trees will send out a flush of healthy new growth in 2-3 weeks. If the buds were damaged or killed, though, the tree will have a hard time recovering and will likely die. There are several steps that can be taken throughout the growing season to minimize this problem.

• In late summer – mid-August to mid-September – allow the trees to become slightly drought stressed. This will start the winter hardening process earlier.

• Following this stress period, keep trees well-watered right until freeze-up. This may help increase the hydration status of trees going into winter.

• Anti-transpirants have been used in North Dakota with mixed results. Once applied, these products prevent water loss for about 3 months, and must therefore be applied sometime in December.

SUNFLOWER ESTABLISHMENT

Hans Kandel

Extension Agronomist

hans.kandel@ndsu.edu

 High sunflower yields require attention to detail.  Sunflower prices are attractive and growers are looking to maximize the profit potential of the farm. Sunflower fit s well into a small grain cropping rotation. Planting a broadleaf crop in rotation with small grains can provide a means to reduce certain diseases in wheat and durum including tan spot, septoria and certain root rots.

Selection of the sunflower hybrid should be based on test results showing high yield potential, disease resistance, and high percent oil content. Seed germination should be high and seed size uniform with no cracking. Timeliness is the key to all good crop management. Long term optimum planting dates for sunflower in ND have been from May 20 to June 5th although yields are generally higher with mid-May to late-May planting dates compared to June planting dates in most ND locations. The sunflower crop will mature in about 95-110 days after emergence.

Special attention should be given when seeding the sunflower crop. Correct plant populations depend on soil type and moisture conditions. Oil sunflower plants per acre should be around 20,000-22,000 plants on heavy soils and 16,000-18,000 plants per acre on lighter soils and low rainfall areas. For confectionary sunflower, recommended populations are lower. For solid seeded sunflower the desired population at harvest is around 26,000 plants per acre. To obtain these recommended populations overplant by 15 percent. Under dry conditions producers may want to reduce the plant populations because if a drought occurs during the growing season high sunflower populations may exhibit severe signs of moisture stress including small heads. Plant to a depth of 1.5 to 2 inches if moisture is available in the top soil. Seeds can be placed deeper under dry conditions, but not more than three inches. Larger sized seed is best for deep seeding.

During the sunflower survey in the fall of 2007 plant stand and uneven distribution were identified as two reasons for lower production. Even seed distribution is critical. Therefore it is important to check the planting depth and seed drop at planting time. Driving too fast may cause skips and irregular seed placement. A good start to the season begins with attention paid to planting. It is also important to monitor the crop for insect problems from early emergence throughout the growing season.

MANAGING POOR STANDS OF WINTER WHEAT

Joel Ransom

Extension Agronomist for Cereal Crops

Joel.ransom@ndsu.edu

 The cool spring weather has slowed the development of winter wheat this spring. Nevertheless, now is the time to access winter wheat stands and make decisions on what to do to when stands suboptimal. In the eastern part of the state where snow cover was excellent during the winter, winter wheat appears to have survived the winter well and many fields are showing excellent spring vigor. In parts of the state where fall establishment was limited by poor moisture and where there was little snow cover during the winter; reports of winter survival are more variable. The questions now are what constitutes a poor stand and how to manage fields that have sub-optimal stands. Plant stands should be accurately assessed before determining an appropriate action. At first glance plant stands can look worse than it really are. When winter survival is not uniform, focus only on those parts of the field that will likely need replanting. Within these parts of the field count four or five randomly selected areas using a square yard quadrant or something similar with a known area. Winter wheat has the ability to tiller and filling gaps better than other classes of wheat, especially if the weather is cool and moisture is not constraining and fairly large reductions in the optimum plant density can be tolerated before it becomes more profitable to replant small grains. For winter wheat, consider replanting when stands are below 5-10 plants/ft2. If you decide to replant the entire field with spring wheat, use a higher seeding rate to compensate for reduced tillering if planting occurs after May 20th. You should also consider using early maturing varieties (varieties from SD tend to be among the earliest adapted to ND) or a variety that is known to handle the heat (i.e. Steele-ND and Howard are NDSU releases that handle the heat well). For fields with small patches of poor stands the best option is probably to leave the field and do a good job of weed control. For fields with very large patches with few or no plants, planting something to reduce weed growth and soil erosion is recommended. Some farmers have reported good results form planting spring wheat to fill in such gaps. Nevertheless, spring wheat matures later than winter wheat so harvest can be problematic. Furthermore, mixing wheat classes can cause problems at the elevator. Planting winter wheat into large gaps can also be an option. Winter wheat planted in the spring will not vernalize so it will not produce a head, but will provide ground cover until harvest. Remember that any tillage in the dry parts of the state will further dry out the soil, making the establishment of spring seeded crops difficult. Check with your crop insurance agent before destroying your wheat field.

NDAWN UPDATE

The Golden Valley County NDAWN station is one of 70 in the state that provides up to date weather information.  Each station will report accurate information for an approximate 20 mile radius.  Information available from the site include growing degree days (GDD), soil temps, and disease forecasting models.  The Golden Valley Station is located 9 miles south of Beach.  The site is sponsored by the Golva Co-op Elevator and the Golden Valley Ag Improvement Association.  For current weather averages for the last 10 minutes, the station can be reached by telephone at 872-3016. 

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