Planting wheat early can cause problems later
With the recent rains across Kansas, some producers may be considering planting wheat earlier than the optimum planting dates to take advantage of topsoil moisture, according to the Kansas Wheat Commission.
There are a number of issues to take into account when considering early planting of wheat. Planting earlier than normal will cause excessive fall growth, may use up available surface moisture and may ultimately result in winterkill damage. This is especially concerning with a killing-freeze in late fall as the wheat continues to grow and use moisture later in the season.
There are other problems associated with early plantings. Wheat streak mosaic virus (WSMV) is a disease that is carried to wheat plants by the wheat curl mite. WSMV causes stunting and yellow streaking on the leaves. Many fields are completely destroyed. In most cases, infection can be traced to a nearby field of volunteer wheat.
Last year in Kansas, there were more problems than normal because of the warm and dry weather in the winter and spring. Control of volunteer wheat is the main defense against wheat streak mosaic. Growers should destroy all volunteer wheat, either with herbicides or cultivation, within one-half mile of their field at least two weeks prior to planting.
"The second control is to avoid early planting," says U.S. Department of Agriculture-Agricultural Research Service plant pathologist Bob Bowden. "Early planting allows the mites plenty of time to move into the field, reproduce and spread."
Some producers wait until the last possible moment to control volunteer wheat and if a field of volunteer wheat is within a half-mile or so of a newly planted wheat field, the likelihood of the newly planted field becoming infected with wheat streak mosaic increases tremendously.
"The third control is to plant a variety with resistance to the virus or the curl mite," Bowman says.
RonL is a new wheat streak mosaic virus-resistant variety released by Kansas State University this fall. KSU wheat breeder Joe Martin warns against early planting of RonL because "the wheat streak mosaic virus resistance is temperature sensitive and can break down if the variety is exposed to high temperatures while it is still in a vegetative growth stage.
"We have achieved complete wheat streak mosaic virus control when the planting date is delayed to the middle of the optimum planting dates for an area," Martin says. "If the resistance in RonL breaks down, its yields and test weight are no better than any other susceptible variety."
Last year in western Kansas, with the excessive fall growth and good moisture conditions, a considerable amount of leaf rust was observed. Early plantings tend to suffer from Hessian fly infestations because there's a "green" bridge between wheat crops that can harbor Hessian fly. Also, we often see more crown/root rots associated with early plantings into warm soils.
Although wheat producers might be tempted to take advantage of recent moisture and get wheat seed in the ground, these disease possibilities should be taken into consideration.