It takes rain during bloom to cause wheat to be infected with head scab. We checked five fields from the southwest corner to the north central portion of Butler County, Ohio and sure enough, there was essentially no scab in the wheat. That is what would be predicted with as little rain as we received in May.

We can’t say the same about Barley Yellow Dwarf virus. This disease, spread by aphid feeding, causes the leaves to turn purple or a dark yellow and the plant to be stunted. The most severely affected wheat was probably infected in the fall. A suggested method to help control the infection is to plant after the fly-free date. Fields that show the most symptoms are fields that were big and lush last fall and therefore attractive to the aphid.
Stagonospora Nodorum Leaf and Glume Blotch is bad on some varieties. It has killed many of the lower leaves and has affected the top two leaves.

These leaves provide the energy for grain fill. Many of the heads are covered with brown blotches on the glumes.

The dry weather and heat have ripened the crop much earlier than normal. Wheat harvest may begin as early as June 20. Usual harvest would not begin until the first week of July.

Dry soil conditions have resulted in delayed and uneven emergence in many corn and soybean fields. Soil moisture conditions remain inadequate for germination and emergence in some fields. What are the prospects for crop establishment in such fields? We’ve been receiving questions about the viability of soybean seeds whose germination was “suspended” due to drying soil.

Seeds that have swollen by taking up water, but cannot complete germination due to lack of adequate soil water, may be unable to germinate, once water is available. The critical moisture content for germination of soybean seeds is 55 percent; for corn, it is 35 percent. Once soybean seed moisture content exceeds 55 percent, it is committed to germinate. Any drying back at this point will result in death of the seed/seedling. Seeds in which the seed coat is broken and a root emerges would require moisture content in excess of 55 percent. New cells need at least that much water to function or they will die.

To determine if seeds whose germination was suspended due to drying soil are still capable of germination, you can dig them up and wrap them in a moistened paper towel in a warm place to see if they germinate. Keep towels moist and count the number of seeds that germinate after one to two days.

Readers with questions or comments for Steve Bartels may write to him in care of this publication.

This farm news was published in the June 13, 2007 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.