Natural incidence of pathogenic fungi on stink bug pests in Argentinian rice paddies

FUENTES RODRÍGUEZ, D.; TOLEDO, A.V.; PEDRINI, N.; SOSA, A.; SANTANA, M.; GERVAZONI, P.; DELLAPÉ, G.; FRANCESCHINI, C.

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA

Wiley-Blackwell Publishing Ltd

Año: 2022

Entomopathogenic fungi (EF) are important biocontrol agents, due to their wide host range, easy application, and compatibility with phytosanitary products. Stink bugs (Pentatomidae) are the most important rice pests in Argentina; although there is information on the pathogenicity of EF against them in rice fields, the natural incidence of EF, and especially their association with stink bug species and plant characteristics, is largely unexplored. The aims of this study were: to record the natural incidence of EF on Pentatomidae pests in Argentinian paddies; to assess the relationship between the incidence of EF, the feeding guild occupied by stink bugs, and the rice cultivars used; and to perform a phylogenetic analysis of the EF recorded. Sampling was conducted in the target rice fields throughout the rice-growing season (2017-2018), during which adult individuals of Tibraca limbativentris and Oebalus spp. were manually collected for examination and evidence of mycelial development. Of the 780 individuals examined, 182 infected individuals were recorded from which it was possible to isolate three strains of Beauveria bassiana s.l., five of Metarhizium anisopliae s.l., and four of Purpureocillium lilacinum (Ascomycota: Hypocreales). The occurrence of the three species of EF was significantly higher in T. limbativentris and depended on the feeding guild of the stink bug (stem feeder) as well as on plant architecture (variety) being higher in the shorter rice cultivar. The results obtained illustrate the potential of using native strains of EF in integrated management for stink bug pests of rice.