Oct 18, 2013 - 05:31 AM
I'll let Ron answer about the hydramethylnon and the maxforce as I havent dealt with roaches before.
As far as switching insecticides quarterly goes, it is a good idea with roaches due to how prolific their life cycles are. The catch is one doesnt rotate from bifen to demon to lambda cyhalothrin, you must rotate insecticide classes. A pyrethroid is a pyrethroid regardless of brand name or active ingredient. The rotation should be from a pyrethroid class to a carbamate or other non pyrethroid/pyrethrin class.
Oct 18, 2013 - 08:35 AM
Hydramethylon takes a few days to kill the cockroaches once eaten. It is not an instant kill.
If the bait stays dry indoors and at a relatively constant temperature, it should last a few weeks. Problem is that this is seldom the case. If applied under the house, it can get wet, damp, etc. I don't recommend using it as a scatter bait in living areas, but if you want to do it sparingly in the garage, store rooms, etc, then that would be OK.
I prefer using it outdoors, and in areas where they might frequent. In this environment, it won't last long. The hydramethylnon is sprayed onto a food particle such as corn cob bits, etc. It all goes bad fairly quickly.
Chemical rotation should be done every time you use chemicals. However, you are not dealing with an insect that has a prolific birthing cycle. American cockroaches are considered "occasional invaders" in most areas of the country. They are not fast breeders, and they usually don't infest like other species of cockroaches do.
Most pesticides outdoors don't last. If it rains, most wash away and dilute. It doesn't matter what it is. There is nothing that will last outdoors very long. The best practice is to continually treat on a preventive basis. How often is up to you. I recommend at least every 90 days.