Episode 20 of Battle for the Belt is now available: https://www.youtube.com/watch?v=jjROATllSms
In Episode 20, Dr. Aaron Wilson, OSU Extension Ag Weather & Climate Field Specialist and State Climatologist of Ohio, gives us an August weather update!
What’s happening in the field?
Western
This past week at the Western Agricultural Research Station, crops made a lot of progress toward maturity. For corn, planting dates one and two are both fully at the R5 stage (dent), with the 100-day, 107-day, 111-day, and 115-day hybrids. Planting date three is at R4 (dough) for most relative maturities. Planting date four is at R3 (milk) and planting date five is at V16 getting ready to tassel very soon (Figure 1.).
For diseases in corn, all five planting dates have had tar spot identified at this location. The plating dates that are at R5 have the greatest amount of disease.. Tar spot came into this field in early July, after the first planting date entered R1 but the other planting dates were not affected until later. Other diseases like gray leaf spot and northern corn leaf blight are present but at very low incidence and severity. Eye spot has been at this location in late reproductive stages.
The soybeans are almost all in different stages of R5 at Western, except planting date five which just entered the beginning pod or R3 stage. The R5 stage (Figure 2) begins when one pod within the top four nodes on the main stem of the plant has a seed that is only 1/8th of an inch long. On the other hand, R6 is when the pod contains a green seed that fills the pod cavity at one of the four uppermost nodes. Vegetative growth stops midway between R5 and R6. Planting dates one and two have stopped putting on vegetative growth and flowering. Planting date one flowered between May 28th and stopped on August 8th.
For diseases in soybeans, the only disease pressure seems to be from septoria brown spot and bacterial leaf blight. These are only on the lower canopy and there is no disease in the upper canopy. Defoliation has been increasing with the age of the plant, but the average severity has been about 3%.
Northwest
At the Northwest location planting date one corn is at the R3-milk stage, and planting date two is at the R2-blister stage. The 100-day hybrid in planting date three is silking (R1) but the rest of planting date three is at V15. Planting date four is at V13 and planting date five is at V11. The soybeans for planting dates one and two began R5, planting dates three and four are at R3, and planting date five is at R2.
The disease pressure here for both crops has been very low. Generally, tar spot moves into this location first and it has not been identified here, only low amounts of eye spot. For soybeans, low amounts of Septoria brown spots have been identified, but thankfully no disease of yield-limiting significance.
Wooster
At the Wooster location, the first two planting dates of corn are at the R4-dough stage. Planting date three is at R1-silking, planting date four is at V15 and planting date five is at V11. The soybean from planting date one to planting date three is at R5, planting date four is at R3 and planting date five is at R2.
For corn at this location, tar spot has been found, and only small amounts of gray leaf spot. For the soybeans, only bacterial leaf spot and septoria brown spot have been found. This has been a relatively low disease year for soybeans at all locations.
The summary of locations, last week’s weather, planting dates, GDDs and stages is presented in Table 1.
Table 1. Weekly weather conditions for each planting date at the Western Agricultural Research Station, Northwest Agricultural Research Station, and Wooster Campus, with the day of planting, soil, air temperature averages, and Growing Degree Days (GDDs) from August 5th to August 11th. Information from CFAES Weather System (https://weather.cfaes.osu.edu/).
