Assessment of how effective the CAFARAN ® insecticide (solid paste bait in small plastic containers and including 24% of boric acid) is against the German cockroach (Blatella germanica L.) Report N° 8.128 Aims : To assess how effective the insecticide manufactured by CAFARAN ® is against the German cockroach in conditions as close as possible to what happens in practice (limited treatment limited to surfaces where cockroaches come but do not stay). Summary : CAFARAN ® was tried out in an experimental framework reproducing conditions close to what happens in practice. CAFARAN ® performed very well against the German cockroach even though it took a while longer to have an effect than a conventional insecticide, such as pyrethroid or organophosphate. 1. Specific testing conditions Locality: Gembloux (Belgium) Period when the experiment was performed: January - February 1995 Ambient conditions: During the test, the temperature was kept at between 19°C and 22°C. 2. Equipment and method: 2.1. Organism under investigation: German cockroach (Blatella germanic L.) from a group that had never come into contact with insecticides, so had not developed any resistance to a product. The cockroaches used in the test were different ages. 2.2. Treatments under investigation: Cage 1 : One CAFARAN ® strip per cage The experiment was carried out in 0.3 m x 1.0 m x 0.3 m plexiglass cages. At one end was a feeding trough filled with dog food (food commonly used in the group from which the cockroaches came) and at the other end a shelter made from egg boxes. At the side of this was a drinking trough. Within this context, the cockroaches had a choice between their usual food and the bait under investigation. 25 cockroaches had been placed in each cage on 27.01.95. After three days, that is, 30.01.95, the products were placed in the different cages due to undergo a treatment. Up until then no deaths had been reported. 2.4. Observations: Checks were made daily for a period of 23 days. Deaths were noted each time they were discovered. 3. Findings: Rate of mortality Cage 1 : One CAFARAN ® strip per cage Applying CAFARAN ® (either in small containers or in dispersed fragments) to sites where cockroaches visit proves to be an effective method for controlling these insects. The second method (dispersed fragments) acts much faster than the first one (containers). When strips were used, their constant effectiveness did not vary fromone cage to another, but insect deaths were spread out over three weeks. In cages were the product was applied in the form of dispersed fragments, on the other hand, all cockroaches perished within a week. 5. Conclusion: CAFARAN ® , a hard paste bait containing 24% boric acid, may be regarded as effective enough to combat the German cockroach (Blatella germanica L.) in a residential setting. The treatment has to be focused on areas where cockroaches visit and be applied either in the form of self-adhesive plastic strips, or fragments to be dispersed. Gembloux, March 3, 1995 |