Aphids Showing Up In Wheat Fields And Possibly Soilborne Mosaic Virus
LAMAR, MO.
Wheat is in the tillering stage. “Remember, the best time to fertilize wheat is right before jointing. That is the time when wheat really starts to grow as it develops the head and uses nitrogen most efficiently,” said Jill Scheidt, agronomy specialist with University of Missouri Extension.
Not many aphids were seen this week, 1-2 per foot of row. The threshold level for bird cherry-oat aphid, the olive green aphid identified by the red band near their rear, is 12-15 per foot of row.
“Aphids are typically found on the underside of the leaf and if temperatures are cooler, make sure to look near the crown of the plants, as aphids tend to feed closer to soil level during cooler periods,” said Scheidt.
Warrior and Mustang are labeled to control aphids in wheat.
Wheat soilborne mosaic virus or wheat spindle streak was seen in one field.
A lab test must be performed to confirm and correctly identify which virus disease. Both these diseases occur if there are wet conditions after planting in the fall or late winter/early spring.
Symptoms appear as yellow-green streaks and are most obvious when the temperatures are around 50 degrees and symptoms dissipate as temperatures warm.
“If viruses often occur in the field, it is important to correctly identify the disease to take preventative management since there are no fungicides to treat viruses,” said Scheidt. ∆