Fabres, G. 1981 Premier quantification du phenomene de gradation des populations de Phenacoccus manihoti Matile-Ferrero (Hom. Pseudococcidae) en Republique Populaire du Congo.. Agronomie 1(6): 483-486.

Notes: Title in English: [Preliminary data on the outbreak of populations of Phenacoccus manihoti Matile-Ferrer (Hom. Pseudococcidae) in Congo.] The results are presented of studies in 1979 on the bionomics of Phenacoccus manihoti Matile-Ferrero on cassava near Brazzaville, Congo. Leaves and shoots were sampled weekly to determine the abundance of the pest. There were 9 generations in 1979. Populations remained low throughout the rainy season (November-May) but increased rapidly during the dry season to reach levels of 70 scale insects/shoot by late October, by which time all the plants and all the shoots were infested. Rainfall appeared to be the main factor involved in reducing populations.