Population of the White Date Palm Scale Insect, Parlatoria blanchardi and Mortality Factors Acting their Population at New Damietta District

Abstract

Population fluctuation of the total and living individuals of the white date palm scale insect, Parlatoria blanchardi was studied for two successive years, 2021 and 2022, in New Damietta district. The insect pest had six and seven peaks of abundance during the first and second years, respectively. The highest peaks of the total population occurred in the beginning of January, 2021 and Mid-November, 2022 and represented by 1520 and 1362 scales/100 leaflets, respectively. The highest peaks of living scales occurred in the beginning of December 2021 and Mid-November 2022 and represented by 778 and 968 scales/ 100 leaflets, respectively. The annual average number of total insect population was higher during the second year than the first year and represented by 686.1 ± 85.02 and 617.6 ± 114.42 scales/100 leaflets, respectively. Moreover, the annual average number of the living population was greater during the second year than the first year. The unknown mortality factors achieved the highest mortality in insect population during Winter season in the first year and during Autumn season during the second year. Aphytis spp. Contributed with the lowest performance in total population pest mortality during summer season, whereas both of Encarsia citrina and predators contributed less during Spring season of 2021 and Autumn season of 2022.