Influences of varying host: parasitoid ratios on parasitism of whitefly by three different parasitoid species

Li Lin,Jianhui Wu,Shaukat Ali

doi:10.1186/s41938-018-0050-3

Abstract

This study reports the effects of different host: parasitoid ratios on parasitic behavior and functional response of three different parasitoid species (Eretmocerus sp. nr. furuhashii, Encarsia bimaculata, and Encarsia sophia) attacking the sweetpotato whitefly, Bemisiatabaci, under laboratory conditions. The parasitic ability of three parasitoid species was significantly influenced by the whitefly density. Increasing host density had beneficial effect on parasite efficiency of Er. sp. nr. furuhashii, E. bimaculata, and E. sophia. The rate of instant attack (a) observed for Er. sp. nr. furuhashii, E. bimaculata, and E. sophia was 0.1649, 0.1113, and 0.0655, respectively. Total parasitic time (Th) observed for Er. sp. nr. furuhashii, E. bimaculata, and E. sophia was 0.0737, 0.2325, and 0.1936, respectively. In the second experiment, the parasitical action was also influenced by parasitoid density. At constant host density, the rate of parasitism increased with parasite density up to a certain density followed by a decrease in rate of parasitism with increasing parasitoid density.

Highlights

The sweet potato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest of agricultural crops in different regions of the world (De Barro et al 2011; Barbosa et al 2014)
The number of second instar B. tabaci nymphs was varied while the number of parasitoid females (E. bimaculata, E. sophia, and Er. sp. nr. furuhashii) was held constant
The percentage of parasitism by E. bimaculata was significantly affected by different whitefly densities

Summary

Introduction

The sweet potato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest of agricultural crops in different regions of the world (De Barro et al 2011; Barbosa et al 2014). From the 1980s, B. tabaci Middle East-Asia Minor 1 (MEAM1) cryptic species (previously known as “B biotype”) has drastically increased in distribution. This has been attributed to the development and increase in global trade. Management of B. tabaci has been dominated by the frequent use of broad spectrum conventional chemical pesticides (Wang et al 2010; Liang et al 2012). The consistent use of synthetic chemicals for B. tabaci

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