QUESTION:

Last year I had a disagreement with the lawn care company providing service at my home. During the course of the season the company used Merit for grub control. Within days following the treatment there were significant numbers of pavement ants in the lawn and ornamental gardens. I understand that the material was applied for grubs, and in fact does not have a registration for ants. However, regardless of the fact that Merit is a systemic, it has to have a certain amount of contact/residual activity. I realize that it may not be the material of choice for ant control, but face it.. it is a pesticide! I find it difficult to believe that Merit has no contact ability, and that ants exposed to it will continue life as usual. What would be your take on this? Additionally what would you recommend as a granular application to ornamental gardens for the control of ants?

ANSWER:

Hi Kenneth. I would agree with you that imidacloprid, the active ingredient in Merit, would very easily kill ants as well. In fact, this active ingredient is in an increasing number of other products, including our MasterLine I-Maxx Pro, which is labeled for ant control. It definitely has a contact action on ANY arthropod pest, and since it is non-repellent it should be an excellent choice for ant management. Just because a trade named insecticide does not list all those other insect pests on its Label does not mean, therefore, that it cannot kill those other insects. This is a message we need to keep in mind as we apply pesticides. Most of them are very broad spectrum, and just as easily kill beneficial insects as they do the pest insects we meant to eliminate, and it is important to be certain that we apply the materials in a directed manner so that only the intended pest is affected.

If this lawn care technician was making the argument that the product he was using was capable of killing ONLY those insects named on its Label then it shows a lack of understanding of pesticides, and some training would seem to be called for on the part of their company. Lawn care businesses are increasingly under scrutiny from regulatory agencies for their uses of both pesticides and fertilizers, and runoff from lawns that ends up in nearby waterways is a serious concern. It is my opinion that landscape companies that use pesticides only incidentally to their major business of mowing and other maintenance may pay less attention to pesticide training than do pest control businesses who use pesticides daily. I have spoken with some local landscape maintenance people in my own area who have reinforced this opinion, as they have told me that their company offers no pesticide training, and since they were wearing clothing quite inappropriate for pesticide applications it seemed accurate.

Granular formulations have a few advantages over sprays. When applied to dense foliage or ground covers the granules can sift down through the dry foliage to get to the soil below, where they stand a much better chance of contacting insect pests. This may be accurate for covers of rock or bark as well. Granules often last longer, as they tend to release the active ingredient more slowly, extending the length of time the a.i. may be available to the pests. However, there are some drawbacks as well, and one of these is calibration. We need to ensure we actually know how much product we are applying to a given square footage of soil, as the product labels mandate this. We also need to stay within the label allowances for where the product can be applied, such as a stated distance out from the foundation. I also have heard complaints of "spotting" on the paint of cars where granules landed during a careless application, and my question to that person was how on Earth did the granules end up on the roof of the car?? Different products have different densities, so proper measurement is needed, they have differing tendencies for dust, and different sizes of particles, so using the proper setting on the spreader is needed.

One of the longest lasting active ingredients in a granular formulation may be bifenthrin, and this a.i. also may have a reduced repellent nature for a pyrethroid, so this could be a good choice for ant control.