Pathogenicity of three entomopathogenic fungi to Matsucoccus matsumurae.

Weimin Liu,Jing Dong,Jun Wu,Yanfeng Zhang,Yingping Xie,Yaobin Lu,Jiaoliang Xue,Michael Freitag

doi:10.1371/journal.pone.0103350

Abstract

Matsucoccus matsumurae (Kuwana) (Hemiptera: Coccoidea: Matsucoccidae) is an invasive alien species and a destructive pest of two native Chinese pines, Pinus tabulaeformis Carr. and P. massoniana Lamb., throughout the eastern regions of China. The pathogenicity of three entomopathogenic fungi, Lecanicillium lecanii strain V3.4504 and V3.4505, Fusarium incarnatum-equiseti strain HEB01 and Lecanicillium fungicola strain HEB02, against M. matsumurae was tested in four instars, to evaluate their potential as a biological control agent. The results showed that the four strains caused disease and death of the scale insect, among which the L. lecanii strains V3.4504 and V3.4505 displayed stronger virulence than the F. incarnatum-equiseti strains HEB01 and L. fungicola strain HEB02 to M. matsumurae in the 2nd-instar nymphs and the adult females. Furthermore, L. lecanii V3.4505 was most virulent to M. matsumurae. The adult females and the male 3rd-instar nymphs of M. matsumurae were susceptible to L. lecanii V3.4505; the adult females were more susceptible at LT50 = 1.96 than the 3rd-instar nymphs at LT50 = 5.67. The body surface structure, cuticle thickness and wax secretions of M. matsumurae impacted the fungal infection. L. lecanii is a promising biocontrol agent, and newly emerged male 3rd-instar nymphs and adult females are a crucial period of the insect’s life cycle for M. matsumurae biocontrol.

Highlights

Pine bast scales are a group of destructive insect pests in pine forests in northern America, eastern Asia and Europe
Lecanicillium lecanii strain V3.4504 and L. lecanii strain V3.4505 were purchased from China General Microbiological Culture Collection Center; strain V3.4504 was originally isolated from a brown planthopper, and strain V3.4505 was originally isolated from a species of scale insect [9]
Infective symptom of M. matsumurae The symptoms of M. matsumurae in response to infection with the entomopathogenic fungus Lecanicillium lecanii strain V3.4505 were observed during the different instar stages

Summary

Introduction

Pine bast scales are a group of destructive insect pests in pine forests in northern America, eastern Asia and Europe. Matsucoccus matsumurae (Kuwana), is the type species of this genus [1,2]. M. matsumurae was first identified in 1905 by Kuwana in Tokyo, Japan, and its original host is the Japanese black pine, Pinus thunbergii Parlatore [3] It first spread abroad from Japan and to the Korean Peninsula. Prior to the 1970s, M. matsumurae was found throughout Liaoning Province in northeast China and spread to Shanghai, Jiangsu and Zhejiang in eastern China [4] In these new territories, M. matsumurae adapted well to the two Chinese native pine species, Pinus tabulaeformis Carr. The damaged trees showed bark dehiscence, needle defoliation, twig wilt, treetop droop, and even death Such heavy infestations attracted considerable attention from forest managers, scientists and governments.

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Conclusion