Fabres, G., & Boussienguet, J. 1981 Bioecologie de la cochenille du manioc (Phenacoccus manihoti Hom. Pseudococcidae) en Republique Populaire du Congo. I. Cycle evolutif et parametres biologiques.. Agronomie Tropicale. Nogent-sur-Marne 36(1): 82-89.

Notes: Phenacoccus manihoti Matile-Ferrero is a species recently introduced from South America into central Africa, where it causes severe damage to cassava crops. As a result of laboratory rearing and field studies, its biological parameters were established, such as the duration of the various development stages, female life-span and fecundity, and the intrinsic growth rate. The effect of temperature and humidity on individual and population development were analysed, especially in the field where the influence of seasonal factors was measured and the succession of generations was observed. The development of a single generation of P. manihoti lasted 30-42 days according to climatic conditions, but this could be reduced to 28 days at a constant laboratory temperature of 27 deg C. In the field in the Congo, the adult life-span of the female averaged 27 days, during which an average of 624 eggs/female were laid, but fecundity was greater at low temperatures. In the laboratory at 26 deg C and 75% RH, the female adult life-span averaged 63 days, but the number of eggs per female averaged only 590.7, which corresponded with the number of eggs laid at high temperatures in the field. Since the theoretical number of mealybugs descending from a single female during the course of a year would be 908 X 1022, ecological factors were obviously very important in limiting populations in the field. Field studies showed that the main factor was heavy rainfall, which drastically reduced populations, especially in November. There were 9 generations a year, of which 7 (between February and November) were fairly abundant, overlapping after August, and 2 (in November-February) were very small but permitted the survival of the pest until the end of the heaviest rains in February.