Waterhemp Biology and Management
Common waterhemp (Amaranthus rudis) presents significant
management challenges for corn and soybean producers. Since 1996,
weed scientists at the University of Illinois have conducted experiments
to determine optimal waterhemp management options in corn and soybean
production systems. Results have indicated that several soil-applied
and postemergence herbicides can provide effective waterhemp control,
but because of the extended germination and emergence characteristics
of waterhemp, sequential management programs are generally more
Research is also underway to examine the shade tolerance and emergence
characteristics of common waterhemp in both conventional and no-tillage
production systems. Preliminary results suggest common waterhemp
is relatively shade tolerant, which may allow the weed to survive
under the crop canopy.
Molecular Techniques to Understand Weed Resistance to Herbicides
Weed biotypes resistant to various herbicide classes continue to
post management challenges for Illinois producers. Weed scientists
at the University of Illinois have begun to utilize molecular biology
techniques to understand weed resistance at the most basic level.
Results have shown that resistance to ALS-inhibiting herbicides
may be transferred between certain Amaranthus species, potentially
escalating the problem.