Ramsey County

Listed below is the numbers from the Crary N.Dawn station.  A reminder, if you would like to check out the station for yourself call 701-398-3008.  Upon completion of your visit touch the star key to end the automation.   Bare soil temperatures, as of 6-11, is 51 degrees.  Maximum wind speed yesterday was 42.6 mph.  Total Rainfall at the Crary station, for 6-11 was 1.24 inches. The total rainfall for the month of June is 2.65”.  April we received .66 inches of precipitation, while May gathered .71 inches.  Going into last week we were behind 1.43 inches of precipitation.

GGD (Growing Degree Days) for corn, using April 15,2008 at the initial planting date, is 323 GGD’S.  Normal GDD for us is 449 meaning we are approximately 126 GDD behind norm. 

It is also that time of year for herbicide applications and I would like to remind everyone to read and follow the label.  As in the past, pesticides regulators will be out and about checking calibrations and mixes. I am also asking everyone to wear their protective equipment.  It is far better to be safe than sorry.  Last but not least, take the 2,3,4 or 5 minutes to write and convey to others where, what and how long the application might and what pesticides were used.  It is also a good idea to write down weather conditions, this could protect from any repercussions down the road.

"GET READY TO SCOUT FOR CEREAL APHIDS"

        Cereal aphids have been reported in South Dakota on winter wheat. These aphids will be migrating into North Dakota soon. The greenbug, English grain aphid and bird cherry oat aphid are the principal species that cause problems in North Dakota small grains.

These aphids transmit the disease barley yellow dwarf virus (yellowing from the tip of the flag leaf - see photograph). When aphid populations are high, the disease can spread quickly through small grain fields. At greatest risk are later-planted fields, which attract migrating aphids that are moving from more mature fields.

Descriptions:

Greenbug - pale green with dark stripe down back.

Bird Cherry Oat Aphid - olive green, brownish patch at bases of cornicles.

English Grain Aphid - bright green with long black cornicles.

When to Scout:  For wheat, field scouting should begin at stem elongation and continue up to the heading stage.

Thresholds for Small Grain Aphids:  English Grain, Bird Cherry Oat, Greenbug

        To protect small grains from yield loss due to aphid feeding, three different treatment thresholds are available:

~85% of stems with at least one aphid present prior to complete heading.

~12-15 aphids per stem prior to complete heading

~100 aphid days prior to complete heading (=0.6 bu/acre yield loss)

        If you averaged 10 aphids per stem and had 12 days to reach heading, you would have 120 aphid days (10 aphids x 12 days). This is above the 100 aphid day threshold and an insecticide should be applied to prevent yield loss. On the other hand, if you averaged only one aphid per stem and had 12 days to reach heading, you would only have 12 aphids days (1 aphid x 12 days). Thus, no control action would be necessary.

Susceptible Crop Growth Stage: 

        Crop growth stage also affects its susceptibility to aphids. Vegetative to boot stages are the most susceptible stages to aphid feeding and subsequent yield loss. For example, in the 4-6 leaf stage, injury caused by aphids is stunting, decreased number of kernels per head, and decreased kernel weight. In the boot stage, only kernel size and kernel weight are affected by aphid feeding (not number of kernels per head). By heading, only kernel weight is affected. After flowering, small grains are less susceptible and producers are discouraged from spraying.

Natural Controls:

      Lady beetles, aphid lions, syrphid fly, and parasitic wasps play a major role in reducing aphid populations. When natural enemies are present in large numbers, and the crop is well developed, farmers are discouraged from spraying fields.

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 RECENT RAINS BRING INCREASED DISEASE RISK

        Recent rains have increased the potential for leaf and head diseases of small grains across many areas of the state.  The NDSU small grains disease forecasting site indicates a more frequent number of favorable infection periods for tan spot of wheat in the past week at many NDAWN locations, and the Fusarium head blight (scab) risk has also increased.  The Fusarium head blight risk should be of concern for producers with winter wheat, as many winter wheat fields are now in the heading stage.

        As mentioned in previous NDSU Crop and Pest Reports, the NDSU disease forecasting site provides information on risk of tan spot, Septoria leaf blotch, leaf rust, and Fusarium head blight (scab), and is available at: http://www.ndsu.edu/scabforecast.  The leaf disease predictions are obtained with choosing leaf stages of the crop, while the forecast for scab risk is only found by clicking on the flowering stage.

        As mentioned in the May 21^st NDSU Crop and Pest Report, another scab forecast site, giving information across many states, is found at: http://www.wheatscab.psu.edu/.   At this web site, provided through several universities and the US Wheat and Barley Scab Initiative, a person clicks on the spring or winter wheat model, then the state, and the scab risk is provided in a colored map.

        The mathematical models used for the NDSU web forecast site and the one provided through Penn State Univ. are the same, but the information sources for the weather that goes into the model are different.  The forecast (for most states) provided through the Penn State web site  is based on RTMA, a mathematical model that estimates weather from a number of computerized sources.  In ND, the model predictions are based on the NDAWN weather station data PLUS the RTMA data.  

        I find both scab forecasting sites very useful.  The NDSU site provides both leaf disease risk and scab risk data plus it is exclusively based on current local weather.  The Penn State site is useful because it provides a broad look at multiple states and allows some 24-48 weather forecasting predictions, as well.  Both sites allow the user to choose the scab susceptibility of the cultivar for spring wheat.

"EARLY SEASON FUNGICIDES FOR WHEAT AND BARLEY"

        Many producers have recently applied fungicides for early season disease control, often in a tank mix with herbicides.  In some cases, some injury has occurred with these applications on the very succulent, thin leafed cuticle, wheat and barley.  In previous years when this type of symptom was observed, the new growth generally looked good and we did not see yield reductions, but did see yield increases with these treatments.   In 2003 at NDSU, we did a number of fungicide + herbicide combination treatments and did not have any injury, a year in which we had a little warmer, sunnier June than we’ve had so far this year.

"FUNGICIDE UPDATE"

        Growers contemplating using fungicides for scab control in the near future should be considering using either Folicur®, Orius®, Tilt®, Proline 3+3®, or Caramba®, as these products are triazoles with the best and safest activity against scab.  In NDSU field tests, the Proline 3+3® or the Caramba® have consistently given the greatest scab and DON (vomitoxin) reductions. 

        Bayer CropScience just announced the registration of Prosaro® fungicide, a pre-mix of prothioconazole and tebuconazole (the same active ingredients of Proline® and Folicur®).  Although Prosaro® just got registered in wheat and barley, Bayer will continue to market the Proline 3+3 (prothiconazole + tebuconazole, not pre-mixed) program for the 2008 growing season, and Bayer says they will transition to Prosaro® in 2009.

      Prosaro® is labeled for wheat and barley for multiple leaf and stem diseases, as well as suppression of Fusarium head blight (scab).  The use rate will be from 6.5 to 8.2 fl oz/acre, with 2 applications per season possible, but not to exceed 8.2 fl oz.

 COOL WEATHER FURTHER DELAYS CORN DEVELOPMENT

        That the weather this spring is cool is not news, but now that we are six weeks into the corn growing season the magnitude of the lag in corn development is becoming a concern. Based on a May 1^st planting date, we are now running between 80 and 143 corn growing degree days (GDDs) behind the long term average, depending on the region of the state (see following table). Since GDDs typically accumulate at the rate of 13 per day in early June, this means that we are currently about six to seven calendar days behind normal corn development.  Furthermore, this means that corn is 1.0 to 1.5 leaves behind normal (about 85 GDDs are required for each new leaf that develops).  It is still early in the season and there is certainly potential for crops to catch up if temperatures during the remainder of the season are above normal.  Nevertheless, if temperatures remain normal, the current delay in crop development will translate into wetter grain at harvest.  From research we conducted last year, we found that a deficit of 80 GDD at harvest could translate into about 2% more moisture in the grain for an adapted hybrid if fall temperatures are normal and harvest is planned for before November 1st. 

        Accumulated corn growing degree days (AGDDs) for selected locations in North Dakota for the period 1 May to 10 June, departures from normal for the same period, and typical daily GDDs for early June (data from NDAWN-http://ndawn.ndsu.nodak.edu/).

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