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

Abstract

The pyriform scale, Protopulvinaria pyriformis Cockerell (Hemiptera: Coccidae) is considered as one of the mostimportant pest infesting fruit trees and ornamental plants. Study of the seasonal fluctuation of nymphs, adult females andtotal population was carried out on guava trees,Psidium guajava ( family Myrtaceae) and the ornamental plant,umbrellatree, Schefflera arboricola (Hayata) (Family: Araliaceae)in Alexandria Governorate, Egyptduring two successive yearsfrom January 2015 till December 2016. P. pyriformis nymphs, adult females and total population achieved two peaks onguava 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 secondyear 2016, while C. carnea showed three peaks in the two years of study on guava. Multi regression analysis indicatedthat 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 compoundeffect of weather factors (E.V.%) recorded 54.21% & 61.69 % of the total population on guava and 64.48% & 55.51% onschefflera in the two year of study, in respect.