According to Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, most wheat in southwest Missouri has started to joint.
“If wheat has begun jointing and nitrogen has not been applied, flying nitrogen over with a plane may be advised in order to reduce damage to the wheat head,” said Scheidt.
Wheat may also be a little behind due to the cold weather but rainfall could have a more costly impact.
“Recent rainfalls may cause loss of nitrogen that has been applied due to leaching that may occur in sandy soils. It is unlikely that there will be enough nitrogen lost though to justify a second application of nitrogen,” said Scheidt.
Scheidt said aphids were seen above threshold levels in wheat that she scouted. Threshold levels for Bird Cherry Oat aphid and Greenbug aphid are 6 aphids/ft. Greenbug and Bird Cherry Oat Aphids vector barley yellow dwarf virus and should be treated for until the flag leaf is present. Recommended treatment for aphids is 3.2 oz/A Warrior or 3.6 oz/A Mustang Max.
“Apply insecticide when temperatures are at or above 60°, when insects are active,” said Scheidt.
Bird Cherry Oat aphids are olive green with red-orange patches along the rear, near the cornicles, which look like tailpipes. Greenbug aphids are pale yellow to pale green with a prominent dark green line running down the length of the back.
“As the season progresses, aphids become less tolerant of cold weather and may die due to extreme changes in temperature. So be sure to scout for aphids on a warm day before applying an insecticide,” said Scheidt.
The weekly field scouting report is sponsored by University of Missouri Extension and Barton County Extension.