OUTCOME OF INSECTICIDE CONTROL OF COCKROACHES (DICTYOPTERA, BLATTELLIDAE) IN PUBLIC-HOUSING IN FRANCE

The current situation in high-rise blocks of low-income flats in the F rench city of Rennes concerning cockroach (Blattella germanica (L.)) p resence and insecticide control was investigated. Based on the indicat ions of an enquiry involving 838 flats, an improved control protocol w as drawn up and applied during a 2 year campaign of insecticide treatm ents in 232 flats. This campaign showed that the proportion of flats w here cockroaches were found was in fact lower than the proportion of f lats in which during the inquiry residents reported seeing cockroaches . During the campaign we found that there was a significantly higher p roportion of cockroach infested flats where residents refused treatmen t than could be revealed by the inquiry. During our campaign, informat ion given to residents and precise knowledge of the cockroach situatio n in each flat enabled us to reduce the number of flats treated unnece ssarily. However, the proportion of flats treated was still important. The results of our campaign stressed two points important for the suc cess of a cockroach control operation using insecticides: (1) Access t o all of the flats is absolutely necessary, and (2) the exact evaluati on of the cockroach population in each flat is difficult, particularly for small populations. (C) 1997 Academic Press Limited.