Controlling perennial weeds with fall-applied glyphosate
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
September is an excellent time to control many hard-to-kill perennial weeds in orchards, vineyards and blueberry plantings. Woody vines (poison ivy, Virginia creeper, wild grape), tree seedlings (poplar, maple) and herbaceous perennials (brambles, horsenettle, milkweed, Canada thistle) are hard to eradicate with soil applied herbicides, but fall treatments with glyphosate can provide excellent control. Fall is when these perennial plants translocate sugars from the leaves to the roots. Glyphosate is also translocated to kill the below-ground parts so the weeds don’t emerge the next year. Of course glyphosate is a non-selective herbicide, so it will also kill trees, grapevines and blueberry bushes if applied to leaves or green stems. Make sure spray does not contact leaves or green bark of your fruit crop. Special equipment such as wick applicators or spray shields may be needed to keep spray off desired plants.
There are many glyphosate products labeled for use on Michigan fruit crops. Some may be more effective than others. Christy Sprague wrote the accompanying article together for an earlier Field Crop CAT Alert. Much of this information applies to glyphosate use in fruit crops.
Dr. Hanson's work is funded in part by MSU's AgBioResearch.