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County Impact Statements - Mississippi County
Resisting Resistant Weeds
Transgenic crops make cotton and soybean production simpler. Non-selective
herbicides are applied to tolerant crops resulting in a very effective and cost
efficient weed control program. The use of the same non-selective herbicide up
to five times in a crop year promotes herbicide resistance. In early May, crop
consultants reported problems controlling marestail after burndown applications
of glyphosate.
An herbicide screen was established to determine if there was a suitable
burndown program with no plant back restrictions to control marestail this crop
season. Results of the screen were shared with participants at the Mississippi
County Field Day. A news article was prepared and shared with local newspapers.
Alternating herbicide chemistries was stressed.
Marestail populations were sampled in the Osceola area and in the south west
corner of the county. Field visits were also requested and made in the eastern
edge of the county.
Approximately one-third of farmers visited encountered problems with
marestail.
This year many post-directed applications of herbicides with different
chemistries, such as the arsenicals, were made. Many producers interviewed plan
to apply 2,4-D or Banval type herbicides earlier in the spring to control
seedling marestail.
U of A Specialist Ken Smith applies treatments in a glyphosate resistant
marestail control demonstration. |
Impacts
Transgenic crops were planted on more than 90% of acres in Mississippi
County.
Burndown, preplant and early post applications of the same herbicde chemistry
selected resistant marestail.
Consultants and producers utilized Extension Agents and Specialists to
document herbicide resistant marestail.
A demonstration was established to assist producers in selecting appropriate
burndown herbicides chemicals.
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