Watch what you are spraying. Especially watch spray drift. There are some folks in Ontario that would love to put a ban on spraying glyphosate in Ontario after a certain date in certain areas. This is because of the drift onto horticulture crops. These high value crops are very sensitive to glyphosate drift. Many of us have been involved in glyphosate drift onto trees. The damage to trees can last for years.
This season it has been difficult to get the spraying done on time. There are a lot of acres still to be sprayed with glyphosate. When you are spraying be sensitive to nearby crops. If your neighbor has a non-Roundup Ready crop beside your crops consider spraying the outside of your field that borders theirs with conventional herbicides. If you do not know what your neighbor has planted then ask them. If there is a wind when you are spraying makes sure that the drift will go towards a Roundup ready crop.
If you have already sprayed your crop and you notice that you have mainly only one weed species left, think resistance or at least tolerance. Ontario has triazine resistant ragweed, pigweed and lamb’s-quarters. We have group two resistant pigweed, lamb’s-quarters, ragweed and foxtail. There is concern that some lamb’s-quarters, once they reach a certain size, can tolerate low levels of glyphosate. These plants have a higher-than-average level of calcium. This calcium ties up the glyphosate.
Finally, this year’s increased acreage of IP soybeans in Ontario has lead to spot shortages of certain herbicides. If you are tank mixing herbicides for post-emergent spraying make sure the tank mix is registered. If it is not registered then talk to someone who can talk intelligently as to whether your desired tank mix will work. Some non-registered tank mixes will work, others will not work and others will work by tweaking the mixture. BF