Some farms around the county received about ½-inch of rain last week. This will sound funny after all the rain we have gotten but we actually needed a little rain.
However, Delaware County and other parts of Ohio are still feeling the effects of the excess rain that we received during May, June and July. About every soybean field I’ve walked has had some type of leaf or stem disease, putting stress on the crop.
According to Anne Dorrance, OSU Extension state specialist, surveys of OSU Extension test plots and her scouting has turned up some expected diseases and some surprises in the lower canopy of many soybean fields.
Here are a few of the diseases that Dorrance suggest farmers scout for:
• Sclerotinia stem rot – Over the next two weeks, Dorrance thinks farmers will begin to see Sclerotinia symptoms move in the soybean canopy. Dorrance and I have both seen stem lesions in fields, especially fields that have a history of Sclerotinia. When scouting for Sclerotinia, look for the white fluffy mycelium that will be evident on the stem, while leaves turn a gray-green and stay on the plant.
• Sudden death syndrome (SDS) – OSU Extension has received several samples and calls over the last week asking about SDS on susceptible varieties. Right now I am only seeing SDS in susceptible varieties. This is similar to what Dorrance is seeing in the North Central Soybean Research soybean variety trial in northwest Ohio. She reports that only the highly susceptible checks have symptoms of sudden death syndrome; resistance is holding in the other varieties.
Plants effected with SDS will show the classic yellow spots between the veins on the leaves which will then turn brown. Symptoms on leaves will continue to progress and eventually the leaflets will drop from the plants, leaving just the petioles attached. The roots and particularly the tap root will be rotted and discolored. After a rain, the blue spores or conidia can be observed on the tap root. The SDS fungus infects the plants shortly after planting and continues to colonize the plant slowly; the piths of infected plants are white and the discoloration in the leaves is due to a toxin that the fungus produces.
• Frogeye leaf spot – I’m getting reports of a lot more of this leaf spot disease than I really expected. However, keep in mind that if you see frogeye and the growth stage of the field is getting close to the R5, spraying will have little economic benefit. The fungus that causes frogeye leaf spot can only infect new leaves, so fungicide applications during late R4 and beyond are no longer necessary.
With Frogeye leaf spot and other diseases, it is important to access the stage of the crop when trying to decide whether to apply a fungicide.
Benefit in the barn
Come enjoy a celebration of agriculture and music on the farm with the Delaware County Farm Bureau and the Central Ohio Symphony, while supporting an important cause – food insecurity in central Ohio. This one-night event is scheduled for Saturday, Aug. 29, from 6 to 9 .pm.
A picnic style dinner with all the fixings by City Barbeque will begin at 6 p.m. and music by the Central Ohio Symphony will follow at 7:30. Hardscrabble Farm, 2514 Skinner Road, Delaware, is the address and tickets are $20 for Farm Bureau members and $25 for the public. Tickets include dinner and concert. There will also be a cash bar of wine and beer. You should bring your own blanket and lawn chair.
We have some tickets at the OSU Extension office or go to http://benefitinthebarn.event.com to buy tickets online. You can call the Farm Bureau office at 614-876-1274 for more information.
Rob Leeds is the Ohio State University Extension educator for agriculture and natural resources in Delaware County.