Cercopora Leaf Blight in Soybean

Nearly all soybean fields in the area are reaching R7 and beyond, where leaves are yellowing and dropping to the ground. While some fields are progressing normally, a large number may have areas that appear to be maturing at a much faster pace. These areas may, in fact, be infected with the Cercospora kikuchii pathogen. Cercospora Leaf Blight is appearing at a very high level this year in the state, as the abundance of rain and heavy morning dew and fog we have been seeing make the presence of the disease more likely.

The blight usually appears first in the upper leaves of the soybean canopy. A bronzing of the leaves occurs, which appears like the natural soybean maturation process. Premature defoliation can of course be detrimental if it occurs prior to seed-fill. The fungus can also cause other problems in soybean. One of those is purple seed stain, which doesn't adversely affect yield, but may cause issues at the market.

Photos from the field

Deer bedding area in Graves County

Nearing harvest in Hickman County

Early morning fog in Muhlenberg County

Crop Update

We are winding down on the 2009 growing season for SoyMVP. Two of our fields are at R7 and are quickly drying down, while the others are at early to late R6. I am anxious to get the yield data and start seeing what worked and what didn't. Although we have hit a few bumps this year (namely wet conditions during planting), we have some really nice comparisons with populations, fertility, and pesticide programs that will be very beneficial.

The growing season is only the first step in the program, as we feel the way the results are reported is just as important. Reporting on that will get started immediately after the numbers are in.

**If you or anyone you know is interested in participating in SoyMVP in 2010, please contact me at jmsarv2@uky.edu or at the UKREC in Princeton at 270-365-7541 ext. 263, or contact your county extension agent.

Norman Borlaug

Norman Borlaug, an immortal in the field of agriculture, has passed away. Borlaug is credited with saving more lives than anyone in human history. His vision was that no person has to go to bed hungry and he spent his life's work proving that.

Norman Borlaug

Pod numbers

I'm getting some interesting results from pod number counts across populations. Pod numbers, and more precisely seed numbers, along with seed size make up the equation that determines seed yield. The following numbers are examples of what I have seen so far in locations where our recommended seeding rates were different than those rates that were utilized by the producer.


Location 1

Producer

Seeding Rate: 140,000
Plant Stand: 116,800
Pods per 10' sample: 1,648
Pods per plant: 49


University

Seeding Rate: 120,000
Plant Stand: 91,200
Pods per 10' sample: 1,428
Pods per plant: 55


Location 2

Producer

Seeding Rate: 150,000
Plant Stand: 114,800
Pods per 10' sample: 1,540
Pods per plant: 47


University

Seeding Rate: 120,000
Plant Stand: 96,840
Pods per 10' sample: 1,720
Pods per plant: 62


Location 3

Producer

Seeding Rate: 169,000
Plant Stand: 122,700
Pods per 10' sample: 1406
Pods per plant: 40


University 1

Seeding Rate: 140,000
Plant Stand: 112,740
Pods per 10' sample: 1300
Pods per plant: 40

University 2

Seeding Rate: 140,000
Plant Stand: 99,900
Pods per 10' sample: 1164
Pods per plant: 41

Again, pod numbers are only part of the equation that goes into making yield. It will be very interesting to see the results from seed weights and of course yield. This will help us to further our knowledge as to how and why soybean plants compensate for lower plant populations and what the limiting factors are for yield.