The effect of entomopathogenic nematodes and fungi against four xylophagous pests

Abstract

The effects of entomopathogenic nematodes EPN (Steinernematidae and Heterorhabditidae) and fungi EPF (Beauveria bassiana) strains were evaluated in laboratory assays against larvae of four xylophagous pests: the Asparagus moth Parahypopta caestrum, the European goat moth Cossus cossus, the pine longhorn Arhopalus syriacus and the black Buprestid Capnodis tenebrionis. Due to their biology and ethology, these insects may be included in the category of pests residing in cryptic habitats. The control of these species is considered difficult, due to the inability of chemical pesticides to penetrate the cryptic habitats and reach the targets. The pathogenicity of the entomopathogenic nematodes and fungi was tested in vitro against the pests. Two experimental models were considered and aimed to imitate the natural environment of the pests, in Petri dishes filled with plant material and inside wood galleries respectively. Main results showed that the majority of the tested strains of nematodes and fungi affected the insects' survival rate. Steinernema feltiae and B. bassiana caused the highest percentage of larval mortality (80-100%). Considering the lack of effective chemical control means, the microbial control of the xylophagous pests by EPN and EPF reveals promising perspectives. Nematodes and fungi are able to penetrate the cryptic habitats because they are living organisms and may be horizontally transmitted by infected hosts. The distribution of EPF as preventive control method and the injection of EPN suspensions to reach and infect the larvae inside the wood galleries can be a combined sustainable control system.

Fungal entomopathogens: a systematic review

“…The B. bassiana is effective against lepidopteran, coleopteran, and hemipteran pests. B. bassiana has also been found to be pathogenic in opposition to the larvae of Capnodis tenebrionis (Linnaeus) (Coleoptera: Buprestidae) in laboratory assays as reported by El Khoury et al (2020) wherein the mortality/transience of C. tenebrionis ran between 26 and 76%.…”

Entomopathogenic nematodes and their symbiotic bacteria: from genes to field uses

“…Other applications of beneficial nematodes have been effective in controlling sciarid dipteran in ornamental nurseries and mushroom farms, the weevil curculionid Curculio nucum on hazels ( 103 ), the thrips Frankliniella occidentalis ( 104 ), the lepidopteran Tuta absoluta on tomato, the chrysomelid Diabrotica virgifera on corn ( 105 ), and slugs and snails in horticulture, with the latter case involving the use of the specific nematode Phasmarhabditis hermaphrodita ( 49 ). Entomopathogenic nematodes have also been found to be effective against xylophagous insects residing in cryptic habitats, such as Capnodis tenebrionis , Arhopalus syriacus , Cossus cossus , and Parahypopta caestrum ( 106 ). Recently, these biological control agents have found broad application in integrated control programs of the Scarab beetle Popillia japonica in large cultivated and non-cultivated areas of Lombardy and Piedmont ( 105 , 106 ), and of the cossid Parahypopta caestrum in the asparagus fields of Apulia ( 107 ).…”

“…Entomopathogenic nematodes have also been found to be effective against xylophagous insects residing in cryptic habitats, such as Capnodis tenebrionis , Arhopalus syriacus , Cossus cossus , and Parahypopta caestrum ( 106 ). Recently, these biological control agents have found broad application in integrated control programs of the Scarab beetle Popillia japonica in large cultivated and non-cultivated areas of Lombardy and Piedmont ( 105 , 106 ), and of the cossid Parahypopta caestrum in the asparagus fields of Apulia ( 107 ).…”

Interactions between Entomopathogenic Fungi and Entomopathogenic Nematodes

“…The combined use of the entomopathogenic fungi (EPF) and nematodes (EPNs) is considered an interesting and effective approach in microbial pest control. The studies conducted so far have focused mainly on the combined use of both groups of biological control agents to increase their insecticidal efficacy under laboratory conditions [ 5 , 6 , 7 , 8 , 9 , 10 ], while their interactions and the possible performances of EPNs and EPF under natural conditions are largely unknown.…”