When fall management fails to eliminate a red clover cover crop what are the options to manage it ahead of soybeans? Ideally one should plant the field to corn and take advantage of red clover’s nitrogen credit (The Ontario corn nitrogen calculator credits it for as much as 73 lbs N/ac). Planting corn also provides […]
If you grow soybeans and have had all or either of Canada fleabane, common ragweed and giant ragweed growing in your fields, the use of pre-plant herbicide tank-mixes will be your best chance at achieving good control of these weeds. Management options for these three weeds are either limited or do not provide acceptable control […]
Wild parsnip is a common weed in eastern Ontario, and is spreading in many other parts of the province. It is a biennial, or short-lived perennial (Figure 1). While wild parsnip does not have the notoriety of giant hogweed, its sap does contain some of the same chemicals (furanocoumarins). When these compounds come in contact […]
The following 10 herbicide injury related scenarios where showcased at the 2013 South West Diagnostic Days held at the University of Guelph, Ridgetown Campus. These scenarios are either duplications of common mishaps that have occured in Ontario or a “look and see” based on farmer or agronomist query. It is important to point out that […]
With three consecutive days of morning frost in many parts of the province, the two most common questions are 1) Will the corn be alright? and 2) When can I start to apply herbicides? Question 1 is answered nicely by Greg Stewart in this story (the abbreviated version is that things will be fine but if […]
co-authors: Dr. Clarence Swanton and Dr. Francois Tardif You may be faced with a scenario where there is an abundance of weeds at or near the maximum leaf-stage for effective control, yet the soybean crop is not at the growth stage specified on the product label. As a producer or consultant, do you focus on […]
With an increase in the number of confirmed populations of glyphosate resistant Canada fleabane in Ontario, many are looking for ways to control these populations and to eliminate any seed production. Management options in soybeans have been discussed in an earlier post, but with weed control in cereal crops imminent it is worth reviewing the […]
Below is a summary of all weed samples sent into the University of Guelph by producers and agronomists that suspected resistance to a particular herbicide during the 2012 season. Also included are herbicide options with different modes of action that are effective on each species. The latest summary of glyphosate resistant Canada fleabane and Giant […]
How do you control chickweed in alfalfa? It is a question asked annually. If you don’t know what chickweed is search it on google images. Of course there is always www.weedinfo.ca. There are three main points on chickweed infesting an alfalfa crop that I have learned over the years. Any herbicide that is effective at controlling chickweed […]
It seems to be an annual question. Do I add ammonium sulfate (AMS) to glyphosate? Will it improve weed control especially if my water source is hard? The short answer is no. Skeptical? I understand. There are many areas within the United States that insist the addition of ammonium sulfate (AMS) to glyphosate is critical, […]
Below are examples of corn and soybean injury demonstrated at the FarmSmart field expo, July 12, Elora Research Station (University of Guelph) Scenario 1: Just this past spring, I had contact with a producer who had accidentally applied Guardian Plus (glyphosate + chlorimuron + flumioxazin) post emergent to his glyphosate tolerant soybeans. This mistake is […]
Below is an overview of herbicide injury scenarios presented at the SouthWest Crop Diagnostic Days . Scenario 1: A field of corn has been replanted due to a poor stand. After planting the producer has decided to remove the existing stand as it is effectively a weed to the new crop. Unfortunately weather delayed the graminicide […]
In any given year, as much as 32,000 acres of Ontario corn is re-planted due to uneconomical plant stands. A two year study conducted at the University of Guelph demonstrated that either Assure II + Sure Mix, Excel Super or Select + Amigo could be applied the day before replanting corn to effectively control a […]
The majority of growers, crop consultants and researchers will tell you that it is always better to manage dandelions in the fall then in the spring. Fall management simply is more effective. The photo below clearly illustrates this point. The outside rounds of this field were managed last fall and there is an obvious difference […]
We in the weed science business are pretty good at telling producer’s to manage perennial weeds in the fall because they are controlled much better. Although its nice to believe without question, quantitative proof is always better. I recently came across a University of Guelph research report from 1977 (I was still in diapers) that […]