Steinernema diaprepesi (Rhabditida: Steinernematidae) parasitizing Gonipterus platensis (Coleoptera: Curculionidae)

Abstract

Entomopathogenic nematodes (EPNs) can control pests due to mutualistic association with bacteria that reproduce and kill the host from septicemia, making the environment favourable for nematode development and reproduction. The objective of this study was to identify an EPN isolate collected in eucalyptus cultivation and to determine its pathogenicity with regard to Gonipterus platensis Marelli (Coleoptera: Curculionidae). Four steel-mesh traps with two seventh-instar Galleria mellonella larvae were buried 5 cm deep in the soil in a commercial Eucalyptus plantation. After 7 days, the traps were packed in plastic bags and transported to laboratory to isolate the EPNs using White traps. The obtained nematodes were multiplied in G. mellonella larvae and identified by sequencing their D2/D3 expansion of the 28S rDNA region by polymerase chain reaction (PCR) and specific primers for ITS regions. Steinernema diaprepesi was identified and inoculated into G. platensis pupae at doses of 500, 1000 and 5000 infective juveniles (IJs) to determine its pathogenicity to this pest. At 8 days after inoculation, the mortality rate of the G. platensis pupae was 80% with the lowest concentration and 100% with the others. The emergence of nematodes and the rapid degradation of G. platensis pupae were observed in those inoculated with IJs. The pathogenicity to the G. platensis pupae indicates potential for using this nematode in the integrated management of this insect.

The survival, development, and reproduction of Gonipterus platensis (Coleoptera: Curculionidae) on the main Eucalyptus (Myrtaceae) genotypes planted in Brazil

“…Damage by G. platensis is low in Australia because of the natural resistance of Eucalyptus species and the suppression of this pest by a diversity of natural enemies ( Valente et al, 2017 ; Valente et al, 2019 ; Afonso et al, 2019 ). However, this insect causes severe damage on exotic Eucalyptus species in some African, American, and European countries ( Reis et al, 2012 ; Souza et al, 2016 ; Valente et al, 2018 ; Schröder et al, 2020 ), resulting in a constant search for alternatives to control this pest ( Nascimento et al., 2017 ; Damascena et al, 2020 ; Schröder et al, 2021 ).…”

Entomopathogenic fungi as the microbial frontline against the alien Eucalyptus pest Gonipterus platensis in Brazil

“…To date, no chemical insecticides have been registered in Brazil against this pest 8 , 9 . Therefore, biological control is the key management strategy adopted for G. platensis control, using natural enemies such as the egg parasitoid Anaphes nitens (Hymenoptera: Mymaridae) 10 , the predator Podisus nigrispinus (Hemiptera: Pentatomidae) 11 and entomopathogenic nematodes 12 . In addition to these diverse biocontrol agents, entomopathogenic fungi are the largest commercially utilized microbial biocontrol agents in Brazil, but few effective fungal strains have been studied for use against ESB 9 .…”

Diferenças entre espécies de besouros do gênero Gonipterus (Coleoptera: Curculionidae) de diferentes estados do Brasil

“…O controle biológico é a principal estratégia de manejo de Gonipterus spp., principalmente com o parasitoide de ovos A. nitens (Jordan et al 2021a). Esse parasitoide pode reduzir as perdas por esse inseto, mas sua menor eficiência em determinadas regiões tem sido atribuída à fatores como a altitude, incompatibilidade parasitoide-hospedeiro e a bactérias endossimbiontes (Damascena et al, 2020;Ribeiro et al, 2023a).…”

“…O controle químico não tem sido eficaz e alguns produtos são restritos pela certificação florestal (Garcia et al, 2019). O controle biológico é feito com o parasitoide de ovos Anaphes nitens Girault (Hymenoptera: Mymaridae) que, mesmo não sendo, totalmente, eficiente em algumas localidades, é a melhor alternativa para o manejo desse inseto (Damascena et al, 2020;Branco et al, 2021).…”