scholarly journals Virulence of Beauveria bassiana Strains Isolated from Cadavers of Colorado Potato Beetle, Leptinotarsa decemlineata

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1077
Author(s):  
Rostislav Zemek ◽  
Jana Konopická ◽  
Eva Jozová ◽  
Oxana Skoková Habuštová
Keyword(s):  
Beauveria Bassiana ◽  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Reference Strain ◽  
The Czech Republic ◽  
Potato Beetle ◽  
Leptinotarsa Decemlineata Say ◽  
Native Strains ◽  
Chemical Pesticides ◽  
Fungus Beauveria Bassiana

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious, widely distributed pest of potato and other crops. This pest is able to defoliate the host plant and cause severe yield loss. Moreover, the pest quickly becomes resistant to many chemical pesticides. Therefore, the development of novel biopesticides targeting this pest is urgently needed. The purpose of this study was to obtain new strains of the entomopathogenic fungus Beauveria bassiana and assess their efficacy against L. decemlineata adults under laboratory conditions. Twelve strains were isolated from cadavers of Colorado potato beetles collected in potato fields in the Czech Republic. Test beetles were treated by suspensions of conidia at the concentration of 1 × 107 spores per milliliter and their survival was recorded daily for three weeks. The results of the bioassays revealed that all new native strains were pathogenic to L. decemlineata adults and caused mortality up to 100% at the end of the trial period with an LT50 of about 7 days. These strains were more virulent than a reference strain GHA and some of them can be recommended for the development of a new mycoinsecticide against L. decemlineata. Our findings also highlight the importance of searching for perspective strains of entomopathogenic fungi among naturally infected hosts.

scholarly journals Efficacy of indigenous isolates of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) against the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Derya Baki ◽  
Hilal Sule Tosun ◽  
Fedai Erler
Keyword(s):  
Beauveria Bassiana ◽  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Phylogenetic Analyses ◽  
Its Region ◽  
Egg Hatching ◽  
Larval Instars ◽  
Potato Beetle ◽  
Leptinotarsa Decemlineata Say ◽  
Negative Environmental Impact

Abstract Background The Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) is one of the most damaging pests of potatoes all over the world as well as in Turkey. Both adults and larvae of this pest feed on the foliage of potatoes, and often cause complete defoliation of potato plants, with considerable yield losses of up to 60%. Chemical control of this pest has induced the selection of resistant CPB populations and negative environmental impact. The aim of the present study was to evaluate the pathogenicity of 14 Turkish isolates of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) against different stages of CPB under laboratory conditions. Results All isolates were tested as conidial suspensions of (1 × 107 conidia/ml), using spray method. The results from pathogenicity assays showed that virulence of tested isolates was variable, and mortality increased with the time of exposure. The highest mortality was seen in larvae of CPB; however, young larvae (1st and 2nd instars) were more susceptible to fungal isolates than older ones (3rd and 4th instars). Four isolates (BbDm-1, BbDs-2, BbMg-2, and BbMp-1) were more pathogenic than others against L. decemlineata, causing mortalities between 96.7 and 100% in the 2 youngest larval instars, respectively, between 91.7 and 96.7% in the 2 oldest larval instars, respectively, and between 93.3 and 96.7% in 0–48-h-old adults, respectively, 9 days post treatment. Furthermore, these 4 isolates had the most potent egg-hatching inhibitory effects (66.7–90%). The results of molecular phylogenetic analyses based on the ITS region sequence indicated that all tested B. bassiana isolates showed a high similarity (99%) with other B. bassiana isolates in GenBank. Conclusions Results suggested that the 4 B. bassiana isolates were highly virulence and had the potential for biological control of CPB. Further tests under field conditions are recommended to validate the laboratory results.

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