The old saying, “Everything's fine until it's not,” comes to mind when dealing with some tough to control perennial weeds in alfalfa production during the summertime. Such was the case for an alfalfa field in the Sacramento Valley, where weed control seemed good up until mid-summer, and then it wasn't. Perennial weeds that started off small and overlooked, grew through the season, persisting through multiple cuttings, including curly dock, plantain, and nutsedge. For tough to control weeds in alfalfa fields, one needs to determine: 1) What types of perennial weeds are present, and 2) How many of them are there, to make a decision on how to manage them. These sorts of weed issues can creep up quickly in older alfalfa...
- Author: Rachael Freeman Long
- Author: Mariano Galla
- Author: Konrad Mathesius
- Author: Sarah Light
Yikes, my weed control didn't work! It's springtime and you're looking at your seedling alfalfa field that you planted late last fall. You have a great stand, but you're not quite satisfied with the level of weed control despite an earlier herbicide application. You still see weeds out there, including bristly oxtongue, thistles, mustard, dandelion, and fiddleneck. You know that weed infestations can weaken young alfalfa plants, retard growth, delay the first cutting, reduce quality, and result in long term damage to crop yield and stand persistence.
The field is still a seedling stand, considered as such until at least the first hay cutting (around the 6-9 leaf stage and a crown is forming). The...