As described in pesticide resistance,
it is very likely that you may run into a population of cockroaches that are not
affected by a particular bug spray. When this happens, the roaches in
question are usually immune to or have a resistance to the entire class of
insecticides and not necessarily just one particular insecticide.
There are three basic ways to approach the challenge of resistant roaches:
The approach of merely switching to another spray that is in the same
class as the original spray can work sometimes. If you have been using a
ready to use, over the counter spray you might have great results by spraying
the infested area with a double strength (what is called the clean out rate)
solution of a professional product. Most pest control operators use Demon
WP, Demon EC, Cynoff WP or Cynoff EC for controlling roaches in residential
dwellings. Tempo WP
and Tempo EC are used in commercial food handling areas, restaurants and
homes. These products are not pre-mixed types of sprays; they are
concentrated products packaged at maximum strength. A ready to use spray
does not pack the punch of a professional concentrate that has been properly
mixed in a fresh solution. (We always advise to use up what you mix up -
the day it is mixed.)
Switch Classes of Insecticide Spray
When pest control operators run into an isolated problem of German cockroaches being resistant to Demon, Cynoff, Demand, Suspend or Tempo we suggest switching to an organophosphate called Orthene Pellets. Orthene is available in pre-measured packs of concentrated pellets or crystals that are mixed with a gallon of water. Orthene is not considered a Restricted Use Pesticide (by Federal guidelines) but it is no longer labeled for use in residential homes. It is used primarily in restaurants where resistant strains of German cockroaches are a problem.
Combine Two Classes of Insecticides
If the problem of roaches that have shown a resistance to a pesticide have not gotten totally out of control, using a good spray that is followed up with a good crack and crevice aerosol will do a good job. A popular combination being used calls for Cypermethrin concentrate and CB-AirDevil aerosol. After mixing and applying a solution of Cypermethrin (Demon or Cynoff) use CB-AirDevil in small cracks, crevices and other roach hiding places. The aerosol (AirDevil) is equipped with a straw that allows for the product to be injected into the areas where roaches, ants and other bugs hide. By combining Cypermethrin (the active ingredient in Cynoff WP, Cynoff EC, Demon WP and Demon EC) with Baygon (the active ingredient in CB-AirDevil) you will be using two totally different classes of products.
Use a Professional Roach Bait
Professional roach baits can save you a great deal of time and money if you have run into a severe German Cockroach problem. There are several roach baits available but the most popular is Maxforce Roach Bait Gel. Maxforce is popular because of the domino effect its active ingredients have on most roaches found in homes and restaurants and ease of application. When baits are used properly, the roaches do most of the work for you.