With winter annual weeds increasing in many no-tilled fields, Mark Loux says mild winters make the problem even worse.
The Ohio State University weed scientist indicates that chickweed, marestail, purple deadnettle and dandelions are the major concerns. Yet their pattern of weed emergence doesn’t necessarily explain why they’re more of a problem in no-tilled fields.
“They appear in no-tilled fields from August to October and then over winter, resuming growth in early spring,” says Loux. “They often flower in April or May, plug up the no-till planter, interfere with no-till crop establishment and harbor insects.”
Jim Kinsella indicates that winter annual weeds are creating serious problems when strip-tilling. With Roundup Ready soybeans applied without added residuals, the Lexington, Ill., no-tiller says winter annuals are becoming more of a concern.
“We try to do most of our weed spraying in the fall to overcome winter annual concerns,” says Kinsella. “Then we only come back as needed with post-emergence herbicides in the spring.”
Dave Feltes says fall-applied burndown herbicides are doing a good job of controlling winter annual weeds. The staffer with the University of Illinois integrated pest management program says this is particularly true when 2,4-D is included in the fall-applied tankmix. This reduces the possibility of crop injury when applied in the spring.
Loux says Ohio research trials indicate that a late spring application of a burndown herbicide killed 80 percent of purple deadnettle weeds. With chickweed, 2 percent was controlled with early spring tillage…