AgAlerts From Griggs County
By John Swenson, Griggs County Extension Agent
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AgAlerts From Griggs County |
Issue # 1, June 1, 2000
The North Dakota Department of Agriculture is offering Project Safe Send again this year. Project Safe Send is a retirement program for out of date or no longer labeled pesticides. Collection sites are located at the Department of Transportation as follows:
Devils Lake, Wednesday, July 12 at the DOT - 2 ½ miles west of Devils Lake - Industrial Park - south side of Hwy # 2.
Cooperstown, Thursday, July 13 at the DOT - one half mile north of Cooperstown.
Jamestown, Monday, July 17 at the DOT - south on Hwy 281, about ½ past the Buffalo Mall on the east side of Hwy 281, just past the camper sales is a section line road (County 39), go east one block
Larimore, Monday, July 10 at the DOT - north side of Larimore, west side of ND 18
Ash trees have been losing their leaves over the past week due to a disease called Ash Anthracnose. This is a fungal disease that occurs in the spring before temperatures get too warm and when there are periods of prolonged wetness, such as we had this past few weeks. The symptoms of ash anthracnose occur on succulent, expanding leaves and shoots. They initially appear as water-soaked spots that rapidly coalesce and enlarge. As these lesions dry out, they become greenish brown to tan or dark brown and cause a crinkled look on the leaf. The leaf rachisees may turn brown, and in the case this year, dark brown to black. If environmental conditions persist at just the right time during leaf and shoot development, premature leaf drop results.
Fortunately, this disease usually doesn't cause serious injury to ash trees. As the weather warms up, the pathogen shuts down. New, unaffected shoots are produced that help to fill in defoliated areas of the tree as the season progresses. Management of this disease rarely requires chemical control. Sanitation in the form of raking up and getting rid of fallen leaves, both in the spring and in the fall, will eliminate the source of the pathogen and prevent primary infections.
Growing Degree Days (GDD) is a tool to predict wheat growth stages accurately by recording the daily temperatures. For small grains, GDD is the average of the daytime high and daytime low minus 32 degrees. When 143 GDD have accumulated, wheat will produce one leaf. Each successive leaf also requires 143 GDD. Knowing the GDD, we can predict when the crop will be in the correct leaf stage for various herbicide applications.
The NDAWN (North Dakota Agricultural Weather Network) has 38 weather stations around the state that will provide GDD for that location. Locations near Griggs County include Dazey, McHenry, Carrington and Northwood. Data from these sites are available on the internet at http://www.ext.nodak.edu/weather/ndawn/listgdd.html. At this location, you can select the location, enter the planting date of the crop in question and the current date and a printout is available that will show the growing degree days. This can be a helpful tool to determine when a field is at the correct stage without having to monitor it.
In 1999 we saw quite a bit of potato leafhopper activity in dry beans and alfalfa. The potato leafhopper invades ND fields each year following migration of the leafhoppers from southern states where they overwinter. These insects are small (1/8 in), pale green, wedge-shaped winged adults that move rapidly by jumping. Sweep nets are useful for confirming their presence in a field. The nymphs will be paler green, lack wings, and characteristically walk sideways when disturbed on the leaf surface. The nymphs will be found on the undersides of the leaves. The nymphs are generally more damaging than the adults since they feed for several weeks on the leaves where they hatch. Feeding injury results in a symptom called "hopper burn". The visual symptoms include leaves changing from green to yellow to brown as they deteriorate. When leaf injury is present, plant growth is impaired. Sometimes the symptoms can appear as burndown herbicide injury.
Thresholds for spraying are when one leafhopper per trifoliate leaf is found. Last year reduced rates of insecticides were used with good results on low adult populations and small plants. Insecticides approved include: Asana XL, Dimethoate EC (Cygon, De-Fend), Endosulfan (Thiodan, Phaser), Lannate*, Malathion 57 EC, Orthene 75S and Penncap-M*.
I have receive some reports of purple corn in the area. Purple corn is a symptom of phosphorus (P) deficiency. Phosphorus deficiency symptoms could be caused by low levels of soil P or by an inability of P to be taken up by corn plants.
Environmental conditions-Regardless of P level, there are also environmental conditions that cause purpling. Cool conditions can effect the uptake of P causing the purple color. As temperature warm up the corn will regain their green color. If this does not happen, then P levels should be checked. Genetics can also have an effect on purpling. There are some very high yield potential corn varieties with a tendency toward early season purpling, especially around the base of the plant. If this is the only sign of purpling in a crop, I would not be concerned. Only be concerned when the entire leaves turn purple. A soil test 0-6 inches for P or, if available, a plant analysis, would confirm an actual P deficiency.
Please Contact Our Office For Additional Information
E-mail: griggs@ndsuext.nodak.edu
Go to the 2000 AgAlert Index Page