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  1. Oklahoma: Canola Schools – August 2 and 4

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  3. Tennessee: Mid-South Ag Finance Conference, Martin, Aug. 3

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  4. Arkansas: RiceTec Field Day, Harrisburg, Aug. 3

    August 3 @ 8:00 am - 5:00 pm
  5. New Mexico: Ag Science Center Field Day, Clovis, Aug. 3

    August 3 @ 8:00 am - 5:00 pm
  6. Texas: Cotton Fiber Quality Conference, Lubbock, Aug. 4

    August 4 @ 8:00 am - 5:00 pm
  7. Arkansas Rice Expo, Stuttgart, Aug. 10

    August 10 @ 8:00 am - 5:00 pm
  8. North Mississippi Row Crops Field Day, Verona, Aug. 11

    August 11 @ 8:00 am - 5:00 pm
  9. Texas: Small Grain Workshop, Brownwood, Aug. 11

    August 11 @ 8:00 am - 5:00 pm
  10. Texas: Pre-Plant Wheat Meeting, Amarillo, Aug. 12

    August 12 @ 8:00 am - 5:00 pm
  11. Kansas: Farm Succession Planning Seminar, Jewell, Aug. 16

    August 16 @ 8:00 am - 5:00 pm
  12. Illinois: Agronomy Day, Savoy, August 18

    August 18 @ 8:00 am - 5:00 pm
  13. Kansas: Farm Risk and Profit Conference, Manhattan, Aug. 18-19

    August 18 @ 8:00 am - August 19 @ 5:00 pm
  14. Kansas: Water Management Field Day, Colby, Aug. 23

    August 23 @ 8:00 am - 5:00 pm
  15. Georgia: Pest Manager Training Workshop, Savannah, Aug. 26

    August 26 @ 8:00 am - 5:00 pm
  16. Louisiana: Sweet Potato Field Day, Chase, Aug. 31

    August 31 @ 8:00 am - 5:00 pm
  17. Georgia Peanut Tour, Tifton, Sept. 13-15

    September 13 @ 8:00 am - September 15 @ 5:00 pm
  18. California Almond Conference, Sacramento, Dec. 6-8

    December 6 @ 8:00 am - December 8 @ 5:00 pm

Kentucky Corn: Keep Watch for Gray Leaf Spot

Ernst Undesser
By Paul Vincelli, University of Kentucky Extension Plant Pathologist July 9, 2013

This is just a reminder of the factors that favor a positive yield response from a strobilurin fungicide in corn. Figure 1 lays this out graphically.

Figure 1. Factors that increase the probability of benefit from a foliar fungicide in corn. The top five factors are often the most important.

Figure 1. Factors that increase the probability of benefit from a foliar fungicide in corn. The top five factors are often the most important.

Disease pressure is, of course, the primary factor determining the probability of a benefit from a foliar fungicide in corn. With all the rain this season, gray leaf spot (Figure 2) may be widely active. Producers may wish to scout fields for evidence of disease activity.

Scouting guidelines for gray leaf spot originated from Iowa State University, and many universities have adopted these with little to no modification. They are:

1. Consider a fungicide application if:
a. The hybrid is rated as susceptible or moderately susceptible, AND,
b. 50 percent of the plants in a field have disease lesions present on the third leaf below the ear leaf or higher prior to tasseling.

2. Consider a fungicide application if:
a. The hybrid is rated as moderately resistant, AND,
b. 50 percent of the plants in a field have disease lesions present on the third leaf below the ear leaf or higher prior to tasseling, AND,
c. Additional factors or conditions that favor disease development are present (See Figure 1)

These are approximate guidelines, and the disease can be unpredictable. Nevertheless, these guidelines can be helpful tools in making rational spray decisions.

Figure 2. Young lesions of gray leaf spot of corn. Image of Doug Jardine, Kansas State University.

Figure 2. Young lesions of gray leaf spot of corn. Image of Doug Jardine, Kansas State University.

Ernst Undesser
By Paul Vincelli, University of Kentucky Extension Plant Pathologist July 9, 2013