How Moisture Changes Weed Control — and What It Means for Canada Thistle

Drought can hide perennial weeds and reduce herbicide performance, while wet years can trigger new flushes. Knowing when to scout, spray and contain patches can keep a small problem from becoming a costly one.Moisture changes which weeds emerge, how well herbicides work and which survivors shape the next problem. For perennial weeds such as Canada thistle, a quiet year above ground may conceal a well-established threat below it. It’s a scenario Thierry Fonville, a research scientist a