Jay Chism, an agronomy specialist with University of Missouri Extension, is seeing aphids on some wheat fields in southwest Missouri.

It is important to monitor aphid populations in wheat fields this fall.

“Reports of small numbers of aphids being discovered should not alarm wheat producers, but if the weather remains mild during the early parts of December, scouting events should be increased,” said Chism.

Mild conditions will also permit beneficial insects such as lady beetles to survive at higher than normal levels, so the news is not all bad.

In most cases the aphid feeding in the fall does not do serious crop damage. However, aphids can vector barley yellow dwarf virus that can reduce yield.

“Greenbug, bird cherry-oat aphid, corn leaf aphid, and the English grain aphid can all infect plants with the barley yellow dwarf virus,” said Chism. “Symptoms may be more severe and yield losses higher if plants are infected in the fall or early in the spring. Infections developing in late spring cause little stunting of plants or yield loss.”

Many producers are adopting high performance wheat production systems and the current thresholds may be outdated.

Recent research in Missouri suggests that aphid threshold levels may need to be more conservative to better protect from loss of potential yield.

Treatment may need to be considered if 10 to 15 aphids are present per linear foot of row during early seedling stage (fall). The old threshold of 50 aphids may not have been an efficient response in Missouri’s field conditions.

“Producers need to look closely,” said Chism. “Aphids can really burrow down in the crown of the plant during cool fall temperatures”.

According to Laura Sweets, plant pathologist with University of Missouri, it is very difficult to estimate the damage that might occur from barley yellow dwarf infection in the fall. Moisture stress may contribute to losses, and disease severity and impact will also be influenced by growing conditions this coming spring and summer.

Crop scouting is an essential part of developing a pest management plan.

Through a regular and systematic field scouting program, pest pressure and crop injury can be determined. Information obtained when wheat farmers’ scout their fields will help determine if any pest management procedures need to be applied.

For more information about scouting for aphids, contact Jay Chism at 417-682-3579. The Barton County Extension Center is located in the Wolf Building at 801 E. 12th in Lamar.

Recommended for you