Mr. Pest Control


Q:

Can a bug die by brushing up against a residual as opposed to walking across a residual?

A:

I don’t know that there’s a difference between a pest brushing up or walking across a residual insecticide. But there is a difference between either of these actions and a pest sitting on a residual insecticide or having it applied directly to them. For example, bed bugs are not likely to pick up a lethal dose by walking across an area treated with a residual pesticide. They are more likely to do so by sitting on the area, although it may take a few days. This is why it’s important to direct residual products to bed bug harborages in order to maximize contact. It’s even better to treat bed bugs (as well as cockroaches, ants, etc.) directly with liquid or dust formulations once you see them. This way, there’s no question that the treatment made contact and will probably provide a lethal dose.

Q:

We have a very stubborn customer that tells us she sees dead American cockroaches all over the place and wants us to come back and retreat. We have retreated twice and she still sees dead roaches. My thinking is that they are dead and what more can we do? They are getting in somewhere, running into our product and dying. She screams at us and tells us that we’re not doing our job. I tried to argue that she needs to seal the sliding glass doors, as there is obviously a problem in the trees and foliage outside. She argued with me and said the gaps in the sliding glass doors are not where the roaches are coming in because she was on the patio when a roach flew by her, hit the glass door and didn’t even try to get through the gap. You just can’t argue with some people, so I prefer to deliver results. Am I better off baiting indoors and outdoors? I read lately that boric acid and syrup make a great poison bait for roaches. By baiting indoors, are we attracting roaches from the outside? Any advice for servicing the exterior and foliage for roaches? Would applying bait outdoors be effective or would I be attracting roaches from other homes?

A:

You’ve treated for American cockroaches three times, but you don’t say how. Regardless, I wouldn’t assume that dead roaches are the result of treatment contact. American cockroaches don’t do very well indoors unless they can stay near a source of high heat and humidity, maybe a roof leak in the attic during the summer. That she continues to have a problem means that the source of the cockroaches hasn’t been identified yet. For the roaches to be originating indoors there needs to be a source of high heat and humidity. It’s also possible that they could be originating from the sewer if spare bathroom drains are allowed to dry out or there is a plumbing break. Otherwise, American cockroaches naturally occur outdoors in South Florida, but not so much for this kind of a problem unless the landscape outdoors attracts these cockroaches to the property. Palm trees often provide harborage for American cockroaches if dead fronds accumulate or the trunk has an overlapping pattern. Dead fronds should be removed and, if you have the appropriate license, you can treat the areas of tree trunks where roaches are living. Debris piles on the property could also be harboring American cockroaches.

Your time is better spent searching for the source of the cockroaches and treating those sources directly, if necessary. I don’t think that just applying bait around the exterior perimeter of the home will be as helpful. If you bait indoors, it needs to be applied directly to cockroach harborages, so you still need to find them. Also, you should not formulate your own pesticides and apply them as part of a service. Legally, PMPs can only apply registered pesticides.