Life history of yam scale, Gonaspidiotus hartii Cockerell (Hemiptera:Diaspididae)

Abstract

Yam scale, Gonaspidiotus hartii Cockerell, is one of the most important insect pests attacking stored yam in the Philippines. In this study, G. hartii was investigated on greater yam Dioscorea data (var Kinampay). The insect underwent three developmental stages: egg, nymph and adult, The total developmental period from egg to adult stage lasted 53-62 (58.77) days for the male and 58-66 (61,74) days for the female. Each female laid 9-196 (89.85) eggs during its entire oviposition period of 3-7 days with 95-100 percent hatchability. A male to female ratio of 1:4.43 was recorded. Adult male lived shorter (1-4 days) than the female (14-22) days.