The presence of cockroaches in urban environments is more and more frequent whatever the type of building. Pest control programmes generally consist of insecticide applications. Several reasons, like their expense or incorrect application, can explain why results are not satisfactory, not to mention the development of insecticide resistance. It must be stressed that the aim of pesticide control in urban areas is not only to reduce the pest population to an acceptable level, but to eliminate it completely. The aim of this investigation was to analyse the results of an insecticide treatment campaign in cockroach (Blattella germanica (L.))-infested council flats in order to understand why these treatments failed. A multivariate analysis revealed that several environmental factors like the number of residents/m2 or the degree of cleanliness could explain, at least in part, the presence Of cockroaches in flats.

Collections of the leaf beetle Henosepilachna elaterii Rossi, 1794 (Protozoa: Microspora) were carried out monthly from July 1988 to June 1991, from melon and cucumber plants in Senegal. Of the 1895 larvae and adults collected and examined, 1223 (64.53%) were infected with Nosema henosepilachnae Toguebaye and Marchand, 1984. The monthly infection prevalence ranged from 51.28% to 87.30%. These observations indicate that the infection due to N. henosepilachnae is prevalent in the natural populations of H. elaterii.

The essential oil extracts of six Malaysian plants, i.e. Curcuma longa, Zingiber officinale, Pandanus odorus, Cinnamomum zeylanicum, Syzygium aromaticum and Cymbopogon citratus, were evaluated for repellent activity against Periplaneta americana using a modification of the ‘two-cylinders’ method. Dose-dependent repellency ranging from 57.1 to 100% was exhibited by all six extracts at the lowest concentration tested (12 ppm).