The Latest

Events

  1. California: Advanced Precision Farming Course Offered Online, Nov. 14 – Dec. 16

    November 14 @ 8:00 am - December 16 @ 5:00 pm
  2. Arkansas: 5 Income Tax Schools in Nov, Dec.

    November 14 @ 8:00 am - December 6 @ 5:00 pm
  3. Mississippi: Row Crop Short Course, Starkville, Dec. 5-7

    December 5 @ 8:00 am - December 7 @ 5:00 pm
  4. California Almond Conference, Sacramento, Dec. 6-8

    December 6 @ 8:00 am - December 8 @ 5:00 pm
  5. Kentucky: 2016 Early Bird Meetings, Dec. 6-8

    December 6 @ 8:00 am - December 8 @ 5:00 pm
  6. Texas Plant Protection Association Conference, Bryan, Dec. 6-7

    December 6 @ 8:00 am - December 7 @ 5:00 pm
  7. ‘Ties to the Land’ Program, Texarkana, Dec. 6

    December 6 @ 8:00 am - 5:00 pm
  8. Kansas: Ag Law & Lease Workshop, Salina, Dec. 6

    December 6 @ 8:00 am - 5:00 pm
  9. Texas: Private Pesticide Applicator License Training, Dec. 6, 15

    December 6 @ 8:00 am - December 15 @ 5:00 pm
  10. Kansas: K-State Program to Help Farmers Deal with Historic Ag Downturn

    December 7, 2016 @ 8:00 am - February 15, 2017 @ 5:00 pm
  11. Texas: Field Crops and Beef Workshop, Edna, Dec. 8

    December 8 @ 8:00 am - 5:00 pm
  12. Texas: High Plains Ag Conference, Lubbock, Dec. 9

    December 9 @ 8:00 am - 5:00 pm
  13. Alabama: Corn and Wheat Short Course, Auburn, Dec. 12-13

    December 12 @ 8:00 am - December 13 @ 5:00 pm
  14. Texas: 55th Blackland Income Growth Conference, Waco, Dec. 13

    December 13 @ 8:00 am - 5:00 pm
  15. Indiana: Crop Adviser Conference, Indianapolis, Dec. 13-14

    December 13 @ 8:00 am - December 14 @ 5:00 pm
  16. Indiana: Beginning Farmer Workshop, Indianapolis, Dec. 14

    December 14 @ 8:00 am - 5:00 pm
  17. Missouri: Crop Management Conference, Columbia, Dec. 15-16

    December 15 @ 8:00 am - December 16 @ 5:00 pm
  18. South Carolina: Ag Marketing Seminar, Myrtle Beach, Jan. 4-6

    January 4, 2017 @ 8:00 am - January 6, 2017 @ 5:00 pm
  19. South Carolina: 4 Upcoming Forest Management Workshops for Woodland Owners

    January 12, 2017 @ 8:00 am - February 10, 2017 @ 5:00 pm
  20. Illinois: 4 Regional Crop Management Conferences in Jan., Feb.

    January 18, 2017 @ 8:00 am - February 15, 2017 @ 5:00 pm
  21. Texas: Red River Crops Conference, Childress Jan. 24-25

    January 24, 2017 @ 8:00 am - January 25, 2017 @ 5:00 pm
  22. Indiana: Ag Business Management Workshop, West Lafayette, Jan. 31 – Feb. 2

    January 31, 2017 @ 8:00 am - February 2, 2017 @ 5:00 pm

Arkansas Corn, Soybeans: Common Foliar Diseases That Don’t Need Fungicides

Ernst Undesser
By Travis Faske, University of Arkansas Extension Plant Pathologist July 3, 2014

Throughout the growing season there are several foliar diseases that affect soybean and corn production in Arkansas. These include a few minor diseases that do not warrant a fungicide because they do not cause any significant yield loss. Currently, a few of these minor soybean and corn diseases are present in fields across the state.

It is common to find downy mildew in practically every soybean field in the mid-South. Typically, it is first observed in the lower canopy then later in the growing season on leaves in upper canopy. Early symptoms are pale green or light yellow lesions on the upper leaf surface. Fuzzy tufts of spores can be observed on the lower leaf surface. Lesions are lighter than frogeye leaf spot, an important disease that also produces fuzzy tufts of spores.

 

Currently, frogeye leaf spot is picking up in many soybean fields across the state. Though downy mildew can appear severe in some cases, commercially available fungicides have little activity on downy mildew; thus, fungicides are not economically beneficial to control this disease.

Ascochyta leaf spot is often found in the lower canopy throughout the growing season. It looks similar to frogeye; however, black fungal fruiting structures (“black dots”) can be seen on the upper leaf surface. This disease often develops in old frogeye leaf spot lesions or spots caused by herbicide injury.

Bacterial leaf blight is often limited to the lower soybean canopy. Angular lesions differentiate this disease from brown spot, another minor disease of soybean that occurs later in the season. Close inspection of the lesions often reveals a “bacterial exudate” on the underside of the leaf. This pathogen can move up the canopy when conditions favor disease later in the growing season, but typically does not move up the canopy during dry growing conditions. A fungicide will not control a bacterial disease thus, fungicides provide no protection for this disease.

Of the few corn diseases that have been observed this year, common rust has been the most frequent. Typically common rust occurs low in the corn canopy; however, this year in rare instances it has been observed in the mid- to upper-canopy. Common rust is a minor pathogen on corn and no fungicides are recommended for control of this disease. Pustule development on the lower leaf surface differentiates common rust from southern rust, which has yet to be reported this year in Arkansas.

Ernst Undesser
By Travis Faske, University of Arkansas Extension Plant Pathologist July 3, 2014