Les pertes de puissance dans les transmissions par engrenages grandes vitesses sont dues au frottement entre les dents, au procédé de lubrification (barbotage ou jet d'huile), au pompage d'un mélange air–huile durant l'engrènement et aux pertes par ventilation de la denture. Des approches complémentaires ont été développées afin de mieux évaluer ces pertes. Cette présentation les résume et propose une analyse des pertes pour deux exemples caractéristiques de transmissions par engrenage.

In the forest zone of Côte d'Ivoire, Vavoua's traps and supports treated with pyriproxyfen® (Sumitomo) have been tested against Glossina palpalis palpalis. The supports were impregnated one time only at the dosage of 2 mg/cm2.

This juvenile hormone mimic acting as growth regulator has a good efficacy: apparent density was reduced by 87% after 2 months and was maintained at this level for 150 days; percentage of nulliparous females was equal to 0 between 40th and 120th days.

Pyriproxyfen may be recommended for the control of animal trypanosomiasis vectors—if it costs less than the insecticides; its slow effect on tsetse population does not favour its use for the control of human African trypanosomiasis which needs a drastic and immediate reduction of Glossina densities.

In Upper Volta the sorghum shootfly is considered dangerous in the case of late and staggered sowing or resowing due generally to irregular rainfall in the beginning of the rainy season. When using fish meal as bait in two different traps, one placed in a humic area and another in a dry area, we followed over a period of 2 years the dynamics of the sorghum shootfly populations at Farako-Bâ. Twenty-two different species of the genus Atherigona (Rondani) were identifed, of which the commonest was A. soccata (Rondani).

Some wild hosts of the sorghum shootfly were also identified. Attention is drawn to the importance of the pest in the case of extensive cultivation of irrigated sorghum in the managed valleys of the country.