de hongos entomopatógenos sobre plagas de chinches en cultivos de arroz argentinos

FUENTES RODRIGUEZ, DANIELA; TOLEDO, ANDREA; GERVAZONI, PAULA BELÉN; BERTUCCI, SABRINA; SOSA, ALEJANDRO; FRANCESCHINI, M. CELESTE

Simposio; V Simposio Chileno de Control Biológico; 2022

Stink bugs (Hemiptera: Pentatomidae), comprise nearly 900 genera and 5,000 species worldwide. Species included in this family are mainly phytophagous and many of them cause enormous economic damage to crops worldwide by feeding on different parts of plants. In Neotropical rice crops,the rice stem stink bug TibracalimbativentrisStål, is one of the most difficult pests to manage. During the rice growing season (spring-summer), this pest remains in the crop, causing annual losses of up to 65.2 kg/ha. Subsequently, during the post-harvest period (autumn-winter) this stink bug goes into diapause and takes refuge in the rice stubble and in the native vegetation around the fields, which allows it to recolonize the crop in the following season. Although its annual cycle in the agroecosystem is well established, it has not been studied in depth whether there are natural mechanisms that help control the populations of this insect consistently throughout the year. Likewise, little is known about the natural enemies in the overwintering refuges of this insect, which could contribute to the reduction of its populations. Therefore, the aim of this study was to record the incidence of entomopathogenic fungi affecting T. limbativentris in rice crops and surrounding vegetation. Seasonal sampling was carried out in different commercial rice fields in Argentina. Adult individuals were collected during winter from the surrounding vegetation and during summer from rice plants. Collected individuals were transported to the laboratory and kept in quarantine. Mortality was recorded daily and the external development of mycelium on the corpses was observed. As a result, three species of entomopathogenic fungi were identified: Metarhizium anisopliae s.l., Beauveria bassianas.l. and Purpureocilliumlilacinum (Ascomycota: Hypocreales), which naturally reduced the winter and summer populations by 33.08% and 49.22%, respectively. These results reveal that entomopathogenic fungi could be good candidates for biological control of T. limbativentris in Argentine rice fields and raise the possibility of exploring the potential of these fungal species to be used in seasonal pest management programs in rice crops