SE IA | DT87 - 9/28/2016 08:53
So spraying in the fall won't have any affect on pigweeds?
We use lots of ALS chemicals, since we're mostly wheat and that's what we use for winter annuals.
Pigweed isn't a winter annual. It is a spring annual weed. The ALS chemistry is still good for a bunch of weeds that we fight...just not pigweed or waterhemp.
Around here the ALS will help control a lot of the large seeded broadleaves (buttonweeds, ragweed, marestail (pre-emerge)). So there is value there to helping hold down your winter annual weeds as the ALS should be around to help control the ragweed (early germinator in spring). But by the time the soil warms up and when the pigweeds start germinating it is usually Mid-May here.
Put out the Fall ALS herbicide, but then follow up in the spring (late April/Early May) with a PPO residual (Valor/Authority/Verdict) and if you can layer on a yellow (Prowl/Treflan), or a long chain fatty acid (Dual, Warrant, Zidua) it should give you a great shot of holding down your pigweed population if you get timely rains.
Around here I am sure there are a handful of waterhemp every year that are susceptible to ALS herbicides, but over 75% aren't and so you have to treat the whole field to control the 75% that aren't susceptible anyway. And untreated waterhemp can grow at 25 waterhemp/square foot. So even if your ALS would have gotten lucky and would control 75% of those 25 plants, you are still left with 6 waterhemp per square foot....Good luck. |
Fall spraying for pigweed
