Q. I am dealing with a German roach issue in an apartment complex broken into buildings. The maintenance people seem to think it’s okay to leave whole panels out under kitchen and bathroom sinks for access to the plumbing. One building has at least 12 units with roaches. I’ve tried everything from baiting, dusting, baiting and dusting, to recently hitting all of the penetrations with a knockdown product, an IGR and again baiting and dusting. What do you recommend?
A. I think you may be throwing too much product at the problem and not thinking of the nature of German cockroaches. They like to live in pockets close to moisture and heat and then they spread out from these areas as the population increases. The key to managing them is to find all of these pockets and to treat them directly. Applying non-repellent products is best because the cockroaches will stay put and you can return to monitor the areas and track treatment progress. There are many non-repellent formulations available, including baits, dust, aerosols and dilutable concentrates.
When repellent products are applied to cockroaches, some may die and others may run to other areas. If a repellent product has a residual, the cockroaches that ran are not going to return to their original harborages, which makes monitoring treatment progress difficult. If I were you, I would start over again and treat the pockets of cockroaches I can find with non-repellent products and, specifically, I’d treat the wall voids with a non-repellent dust. The cockroaches will not die quickly, but the infestation will slowly begin to improve over a few weeks. If the infestation plateaus in improvement, then the problem is that pockets of cockroaches are being overlooked. Treatments don’t seek out cockroaches; they have to be applied directly to them.
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