The Scoop on Foam
Foams are a relatively new tool in the PMPs fight against difficult to control pests. The concept behind using foam is simple – they can do anything a liquid insecticide can do, only more efficiently. If a liquid pesticide is, the liquid cannot flow “up” into a termite gallery or void, it must follow where gravity leads. Foam on the other hand, can “climb” up into galleries, voids and other openings.
Foam formulations are described as a “dry” foam, meaning there is little water applied so it is unlikely to damage surfaces, walls, wooden pieces, or other places applications might be made.
Foam on the other hand, can “climb” up into galleries, voids and other openings.
Additionally, most foams are non-repellent so when insect encounter insecticide residues left behind after the foam dries, they do not avoid the treated surfaces. Foam applications are generally not exposed to UV light and rain so the treatment will not be broken down or moved from the application site.
How to Apply
There are many options for PMPs to make and apply pesticide foam. Mechanical foamers powered by electricity, simple hand pumped compressed air foamers, and commercially available ready-to-use foam in a can, much like shaving cream or hair mousse are available. Most commercially available cans of foam have a 30:1 foam expansion ratio; this means the volume of foam formed to the volume of solution to make the foam. There are many types of pesticides that can be formulated into foam and there are several commercially available foaming concentrates. Never use a foaming concentrate alone; there is no active ingredient in it to control pests.
Most foam applications, traditionally, were made against drywood termites and wood boring beetles.
Never use a foaming concentrate aloneDue to their habits of living inside wood, without contact to moisture, and in small numbers, foam is an excellent choice for control. A small hole is drilled in the wood, with the goal of accessing termite feeding galleries in the wood and foam is applied. Kick out holes (where frass is ejected from galleries) can also be used.
Not Just for Termites
More recently, foam applications have been used to control other pests, such as ants and carpenter bees in wall voids and other places traditional liquid applications are difficult or impossible. Furthermore, some products are not limited to voids; they are also labeled for crack and crevice applications for ant control.
Be patient! Most foams are formulated with non-repellent insecticides. These products are notoriously slow acting; they take time to control insects.
As always be sure to read and follow all pesticide label instructions.