The diel activity patter n of Glossina austeni was studied on the south coast of Kenya, and in the laboratory. In the field, flies were sampled hourly by continuous catch from a standing vehicle, or by traps. In the laboratory, observations were made of the flies' take-off-responses to host odour at various times of the diel cycle, in a flight chamber. The results showed that G. austeni is day-active with some activity throughut the daylight hours, but with significant peaks occurring at 09.00–10.00h and between 14.00 and 17.00h, i.e. a roughly V-shaped pattern.

Chilo spp. are among the most important stem borers of sugar-cane in the Old World. Chemical control is not very effective mainly because of the concealed habit of the borer larvae. Efforts have therefore mostly been directed to alternative methods of control such as cultural practices, varietal resistance, biological control and the use of sex pheromones. Varieties are not normally bred for borer resistance but very susceptible ones tend to eliminate themselves at the early stages of selection. Susceptibility is normally assessed on promising and released varieties. Classical introduction of exotic parasites has more or less reached a saturation point and biological control tends to be oriented towards the possible use of new or cross-bred strains. The importance of entomopathogens as a control component against Chilo spp. needs further studies. A great potential exists in the use of sex pheromones mainly as a means to disrupt mating, as shown by the promising results obtained through trials carried out in various countries. It is very important that the various methods of pest control available be used in combination with one another, taking into account the natural limiting factors of the environment. This would be an important contributing factor towards an objective of optimum yield at minimum cost in the management of Chilo spp. on sugarcane.