The population dynamics of the brown soft scale Coccus hesperidum on Ficus nitida trees was studied for two successive years (1995 and 1996) at Dokki region, Giza Governorate, Egypt. The total density of C. hesperidum population during the first year of investigation (5832 individuals /30 leaves) was higher than that of the second year (3964 individuals /30 leaves). The composite age-structure of C. hesperidum on Ficus nitida trees showed that Preadults, females and gravid females represented 76.28, 10.74 and 12.98% of the total population, respectively in the year 1995 and 81.07, 8.88 and 10.05% of the total population, respectively in the year 1996. Results declared that this insect has four generations in the year. Three and two peaks of abundance for C. hesperidum were recorded during the years 1995 and 1996, respectively. The highest abundance of the insect was recorded at the end of winter in both years of investigation, whereas the lowest abundance was recorded during the 1st of February 1995 and the 1st of August 1996. The rate of monthly variation in the population of C. hesperidum showed that the favorable time for the annual increase of most stages and the total population of this insect occurred in mid-August, the beginning of September and in mid-February. The regression and relationships between selected climactic factors and the total population of C. hesperidum on Ficus nitida trees were studied during the investigation period. |
