The Impact of Climate Change on Seasonal Abundance of ThePyriform Scale, Protopulvinaria Pyriformis (Cockerell) (Hemiptera: Coccidae) and Its Predatorsin Alexandria, Egypt

摘要

The pyriform scale, Protopulvinaria pyriformis Cockerell (Hemiptera: Coccidae) is considered as one of the most important pest infesting fruit trees and ornamental plants. Study of the seasonal fluctuation of nymphs, adult females and total populationwas carried out on guava trees,Psidium gnajava ( family Myrtaceae) and the ornamental plant,umbrella tree, Schefflera arboricola (Hayata) (Family: Araliaceae)in Alexandria Governorate, Egyptduring two successive years from January 2015 till December 2016. P. pyriformis nymphs, adult females and total population achieved two peaks on guava and schefflera in the two years of study. During the course of this study, two predators were associated with P. pryiformis these predators were Scymnus syriacus L. (Coleoptera: Coccinellidae) and Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae). S. syriacus showed four peaks in the first year of study 2015 and three peaks in the second year 2016, while C. carnea showed three peaks in the two years of study on guava. Multi regression analysis indicated that the predators play good effect on the population of P. pryiformis on guava since E.V% was 39.9 % in 2015 and 40.21 % in 2016 while they were less on schefflera (28.76 % & 36.24 % in the two years of study respectively).The compound effect of weather factors (E.V.%) recorded 54.21% & 61.69 % of the total population on guava and 64.48% & 55.51% on schefflera in the two year of study, in respect.