b'Waterhemp plants after frost at end of September.PHOTO: MANITOBA AGRICULTUREWATERHEMPContinued from page 11spreaders of weed seeds and waterhemp seeds are tiny and impossible tocompletelycleanout.Combineswillspreadherbicideresistant seed throughout the entire field and contaminate every field they work in. Waterhemp can germinate post-harvest and produce seed before freeze-up (see photos above). Post-harvest weed control is crucial, through tillage and/or with herbicides that work on pigweeds. Productscontaining2,4-D,MCPAordicamba,orherbicideslike Intruvix, IPCO Bifecta EZ or Smoulder are registered for fall weed control, make sure to follow re-cropping restrictions.Waterhemp is resistant to several herbicide groups, 5 way resis-tance to groups 9, 2, 5, 14 and 27 develops rapidly. Row crops like corn,soybeans,drybeansandsunflowersgivewaterhempample opportunity to grow prior to row closure and there are limited post-emergent weed control options. Waterhemp can be found in cere-als and canola, but usually these crops out-compete waterhemp as they cover the ground quicker and have more in-crop weed control options. There are NO new chemistries coming that control water-hemp, we must use the products we have efficiently, effectively and sustainably so they last as long as possible. Whenseedingsoybeansonfieldswithwaterhempyoucannot spray glyphosate alone. Pre-emergent herbicides with residual activ-ity are a good start for your weed control program. Products like Authority,AuthoritySupreme,DualII,Edge,Fierce,Focus,Heat Complete, IPCO Bifecta EZ, metribuzin + Treflan, Treflan, Valtera, Voraxor and Voraxor Complete offer suppression or control of pig- Waterhemp plant in soybean field, sprayed on second pass. weeds. In-crop you need to be using the Xtend, Xtend Flex or EnlistPHOTO: DENNIS LANGE, MANITOBA AGRICULTUREsystem and spraying the tank mix partner with glyphosate on the first pass or at the first trifoliate. This past season we saw several fields ofincluding pre- and post-emergent products with multiple modes of Xtend beans where glyphosate alone was sprayed first pass and thenaction, mix it up as much as possible. Cover crops may offer some fall waterhemp escapes were noticed. When dicamba was added for theweed suppression particularly if grown after early-harvested crops. If second application it was too late as the waterhemp was way too bigwaterhemp is allowed to set seed in the field then some sort of harvest to be controlled.weed seed control is necessary to limit the amount of seed that hits the Battling waterhemp needs us to use all the tools in the weed controlground. There are several ways to do this, ranging from chaff lining, toolbox. The starting point is a diverse crop rotation with competitivechaff tramlining, bale direct, using chaff wagons, and installing weed crops in the mix and wherever possible use strategic tillage to controlseed destructors on combines to prevent waterhemp seed returning weeds. When growing soybeans, plant in narrow rows as this is moreto the seedbank. We need to do everything possible to stop the spread competitive than wide row beans. In all crops use herbicide mixturesof this weed.12SEED MANITOBA 2024SEEDMB.CA'