Former MSU Extension agent presents weekly IPM report
Weather -- There was 1.25 inches of rain early this week in Ida. At the MAWN weather station near Petersburg, we have accumulated 363 "heat units" (GDD base 50) since March 1, almost exactly at the six year average.
Corn -- Most field corn is spiking to the v2 leaf stage. Dr. Bob Nielsen at Purdue thinks that "mudding in" the planting of corn is worse than delaying till soil conditions dry out. Delayed planting generally coincides with warmer soil temperatures compared to early planted corn. Consequently, stand establishment may be more successful waiting until soils dry out sufficiently. One possible time saver may be to skip any pre-plant tillage. Compaction from using heavy farm equipment over wet soils can block root systems and limit nutrient availability. Wet soils can also reduce soil oxygen levels, which can affect root growth and nutrient uptake.
Wheat -- The armyworm trap was knocked over by a custom applicator in the wheat field and has now been re-installed. Fields are generally at the Feekes growth stage 7, second jointing and will have the flag leaf emerging soon, which is Feekes 8.
The MSU Diagnostic Laboratory is offering free wheat disease diagnosis this season, courtesy of funding from the wheat checkoff program. If possible take pictures of the distribution of the symptoms in the field. These are helpful to show stunting, poor stand issues, differences in color, etc. Images can be emailed email@example.com or printed and included with a physical sample.
To print out a Diagnostic Submittal form and for information about collecting and shipping insect or plant samples, go tohttp://fieldcrop.msu.edu/wheat/ then go the last link of the Wheat Diseases section of the page. If shipping plant specimen samples, overnight or priority delivery is recommended. Do not ship samples on a Friday.
Samples can also be delivered in person to the diagnostic lab. Jerry Heck of Monroe is cooperating on a wheat checkoff funded research project looking at high management practices. These practices include more nitrogen, fungicides and a growth regulator. Results will be compiled with those of other cooperators from around the state and reported later, perhaps at a winter meeting. Cool temperatures and high relative humidity favor the development of Powdery mildew. If the variety has no genetic resistance and if conditions become favorable, a fungicide can be applied to prevent the disease from reaching the flag leaf before grain-fill. Septoria leaf blotch is another disease that is usually spread from the lower to the upper leaves by rain splash.
This disease usually shows up first on the lower leaves as yellowish flecks that later develop into irregularly shaped, brownish-gray lesions, with dark brown to black spots in the center.