Abstract: Triplochiton scleroxylon is a plant species of tropical Africa. It’s known as "Ayous" in Cameroon. It’s soft, light wood and white cream; it can be used industrially and has an economic importance. In Cameroon, the national reforestation programs of T. scleroxylon stumble on the proliferation of psyllids pest of this plant. Two psyllids feed on T. scleroxylon in Cameroon, Diclidophlebia eastopi and D. harrisoni. D. eastopi larvae caused leaf discoloration and stunting of seedlings. D. harrisoni larvae caused leaf curl. Damages are important on young plants. The population dynamics of these two psyllids species was conducted in a natural secondary forest from February 2009 to January 2011. We collected 570 males and 597 females of D. eastopi and 295 males and 269 females of D. harrisoni. The numerical variation of psyllids population in 2009 shown six main generations for D. eastopi and five main generations for D. harrisoni. In 2010, six generations were obtained for D. eastopi against seven generations for D. harrisoni. Some climatic factors influenced the numerical variation of psyllids on T. scleroxylon in Cameroon. The phenology of the host plant seems to be the main biotic factor influencing the numerical variations of psyllids on T. scleroxylon. A better understanding of the population dynamic of psyllids pest of commercial timbers could be very important for an integrated pest management in the tropical forest of Africa.