Identification of Fungi Associated to &amp;lt;i&amp;gt;Pseudips mexicanus&amp;lt;/i&amp;gt; (Curculionidae: Scolytinae) as a Possible Biocontrol Agent

Oscar Burgos-Duenas,Isaac Tello-Salgado,Maria Del Rayo Sanchez-Carbente,Armando Burgos-Solorio

doi:10.11648/j.ajaf.20210904.16

Abstract

Entomopathogenic fungi are an important insect biological control group, however most of the fungi described as biological controllers have a broad spectrum of insect hosts. Pseudips mexicanus is a bark beetle that infests pine-oak forests in Mexico, causing significant economic and ecologic losses. In addition, the infestation alters the ecology of different organisms that coexist in the forest habitat. The search for bark beetle control methods other than pesticides has led to research into biological control procedures based on naturally occurring beetle pathogens. The goal of this paper was the isolation, morphological and molecular identification of fungi that naturally parasitize the bark beetle Pseudips mexicanus, as well as to carry out infection tests to propose a specific biological control alternative to this plague. Associated to this beetle, we have identified four isolates belonging to three genus: Beauveria, Lecanicillium and Trichoderma, within these some species have been used previously as biocontrollers, mainly in agricultural use, in the process of transformation of organic crops. The LVP-2 isolated, which was identified as Beauveria was tested for infection of naturally harvested bark beetles and its pathogenicity was proved, at three days post infection (dpi) most of the individuals presented little mobility of the legs and a swelling of the body was noted, however more studies are needed to determine their viability as plague controllers in Mexican forests.

Highlights

In Mexico there are approximately 870 bark beetle species, which are involved in the active degradation of plant biomass [1]
In this work we showed morphologically and phylogenetically that an isolate of B. bassiana obtained from a bark beetle corpses was capable of acting as an entomopathogenic agent on P. mexicanus, killing the insects in only six days
It has been reported the use of B. bassiana, M. anisopliae to control bark beetles of the genus Ips, species such as I. typogrpahus, I. sexdentatus, Ips grandicollis and Ips calligraphus mostly in Europe, those strains were from commercial sources [56,57,58,59]

Summary

Introduction

In Mexico there are approximately 870 bark beetle species, which are involved in the active degradation of plant biomass [1]. Among the most important bark beetle species that have a major impact in the elimination of large extensions areas of tree forests from North to Central america, are the genus Dendroctonus, Scolytus, Phloeosinus, Ips and Pseudips [2, 3]. Within the more representative bark beetle species are Dendroctonus frontalis, Dendroctonus adjunctus, Dendroctonus mexicanus, Pseudips mexicanus and Ips spp. The last two species are considered secondary bark beetles, meaning that the trees have been colonized previously by other bark beetles’ species, usually from the Dendroctonus genus. When the populations of secondary bark beetles species increase, these are considered primary pests that can result in forest tree population loss [3]

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