Variability of Deltamethrin-Resistant &amp;lt;i&amp;gt;Metarhizium anisopliae&amp;lt;/i&amp;gt; Aggressive Strains Group to a Population of the Cossid Moth from &amp;lt;i&amp;gt;Eucalyptus nitens&amp;lt;/i&amp;gt;

Pedro Romón,Hardus Hatting,Arturo Goldarazena,Juan Carlos Iturrondobeitia

doi:10.4236/ojf.2018.82014

Abstract

Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was used to examine the genetic variability among Metarhizium anisopliae isolates tested to the cossid moth, Coryphodema tristis. All the isolates tightly clustered into one or the other of two groups that diverged at 12%. Results suggested that certain genotypes of the fungus, that grouped together, were able to infect moth larvae while others did not. A fragment of 760 bp, which presents high homology with a host-adaptation related protein coding gene, distinguished between aggressive and non-aggressive isolates. Neither mycelial growth nor sporulation rate or presence of known virulence genes was correlated with mortality values. Some isolates, including the most aggressive isolate ARSEF2518, were compatible with deltamethrin. Deltamethrin treatment killed all the larvae after seven days whereas fungal and mixed treatments respectively reached the same mortality after 28 and 21 days.

Highlights

Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was used to examine the genetic variability among Metarhizium anisopliae isolates tested to the cossid moth, Coryphodema tristis
One primer with reproducible amplified band of 760 bp unique to the aggressive isolates group was selected. This is the first study investigating the aggressiveness of M. anisopliae to C. tristis
RAPD-PCR has been used in a number of surveys of M. anisopliae

Summary

Introduction

Since 2004, it has been found feeding on Eucalyptus nitens in the Carolina-Badplaas-Lothair area in South Africa, resulting in gregarious feeding behavior and extensive damage (Boreham, 2004). The cossid moth has a two-year life cycle in the Western Cape, but the duration of the life cycle in the summer rainfall area is not yet known. Both the main trunks and branches are attacked

Methods

Results

Conclusion