Ground Ivy Control

Objectives:

                The objectives of this experiment were to 1) evaluate 3 different herbicides for their ability to control creeping charlie/ground ivy and 2) determine whether that ability could be improved through tank mixing with an additional herbicide from a different chemical class labeled for ground ivy control.

Materials and Methods:

                Ground ivy (Glechoma hederacea) samples taken from a residential landscape were transplanted into standard 5” diameter pots in a greenhouse and allowed to reestablish for seven days before being treated. The 5” diameter pots were filled with a standard potting soil mix which provided the plants with an optimal growing environment.

                Treatments (table 1) included an untreated control, triclopyr, tenacity, pylex, triclopyr + tenacity, and triclopyr + pylex. Treatments were applied foliarly using a hand-sprayer. Plants were irrigated prior to treatment, with all additional irrigation being withheld until 24-hours post treatment.

                                                                                  Table 1. Treatment and Rate Information

Image 1: Non-treated Ground Ivy

Image 2: Ground Ivy 10 days after Triclopyr only treatment

Image 3: Ground Ivy 10 days after treatment with Tenacity

Image 4: Ground Ivy 10 days after treatment with Pylex

Image 5: Ground Ivy 10 days after being treated with both Triclopyr and Tenacity

Image 6: Ground Ivy 10 days after treatment with Triclopyr and Pylex

Conclusion/Discussion:

                When looking at the above images, it is easy to see the effect these chemicals have on the plant. Tenacity and pylex (trt’s 3 & 4) are both class 27 herbicides (pigment inhibitors). These chemicals are known for their ability to inhibit chlorophyll production, resulting in a bleached/white appearance on the leaves. It is important to note however, that the bleached appearance just means that the plant is affected by the chemical, and does not always guarantee control. In contrast to this, triclopyr, a class 4 herbicide, is known for its plant growth regulating activity. This is evident in the 10-d post treatment photo for treatment 2 above.

                According to the label for both pylex and tenacity, these chemicals can be tank mixed with an additional broadleaf herbicide, such as triclopyr. That was the driving force for this experiment. When reading the label however, it is unclear whether this tank mixture will increase in its effectiveness in controlling hard to kill weeds such as ground ivy. What is clear when reading the label, is that when applied in a mixture, the effect of class 27 herbicides on plants can be altered in the form of less bleaching occurring.

                This effect is evident in the pictures above, where the samples in images 3 and 4 showing signs of complete leaf bleaching (whole leaves turning white), whereas the samples in images 5 and 6 still show signs of bleaching, but a consistent pale green color still remains.

                Depending on who you talk to, the bleaching of plant leaves as a result of application may or may not be a favorable trait. To some, it is viewed as an indicator of progression, and that the chemical is working. Others may view it as a side-effect that could be deemed esthetically unpleasing. For those that fall into this category, tank mixing with an additional broadleaf herbicide may be a way to remedy this.

                While it is hard to say at this point in time, it does appear that the triclopyr addition to the tank mixtures is beneficial. While there is less bleaching occurring on an individual leaf basis, a larger number/bigger surface area of the treatment 5 & 6 pots appear to be affected compared to the treatment 3 & 4 pots, respectively. I will continue to let these samples persist in the greenhouse, and hopefully we will have a more definite answer down the road.

Isaac