Promising native bio-controllers for sustainable pest management in Argentinean rice fields

FUENTES RODRÍGUEZ, D.; GERVAZONI, PAULA B.; TOLEDO, ANDREA; MULIERI, PABLO; AQUINO, DANIEL; FRANCESCHINI, M. C.; SOSA, A.

Chillan

Workshop; V Simposio Chileno de Control Biológico; 2022

Instituto de Investigaciones Agropecuarias (Chile)

Agricultural productivity and sustainability can be positively influenced by the use of indigenousbiodiversity for pest management. Among the most widely used biota for pest biocontrolworldwide, entomopathogenic fungi and parasitoids stand out. However, due to the concernsof regulatory agencies about the importation of alien organisms and their safety to non-targetspecies, it’s important to search native natural enemies for incorporation into sustainablemanagement programmes. This work is aimed at carrying out a bioprospecting to find potentialpest bio-controllers in Argentine rice paddies, focusing on parasitoids (Diptera/Hymenoptera)and entomopathogenic fungi (Hypocreales). We surveyed stink bug pests (adults and eggs), andparasitoid insects during the rice growing season. Also, we measured under laboratoryconditions, the impact of natural enemies on the stink bugs pests Tibracalimbativentris andOebaluspoecilus (Hemiptera: Pentatomidae). As a result, we collected 304 individuals ofHymenoptera and Diptera (7 families each), finding 11 species of native parasitoids. The mostabundant were Telenomus sp. (24.2% of all Hymenoptera collected), Sceliosp. (22.6%), andSepedonea sp. (9.4% of all Diptera collected). In laboratory, 340 individuals of T. limbativentrisand 319 of O. poecilus were tested, and the incidence of natural enemies was recorded in 166of them. We identified 3 species of entomopathogenic fungi, highlighting the impact ofMetarhizium anisopliae on T. limbativentris (24.9% infected individuals). We also detected 3species of dipteran parasitoids on adult stink bugs, recording Beskiaaelops on the two pestspecies. In addition, 1331 eggs of these pests were tested, of which 311 were parasitized byTelenomus sp. In total, 7 potential bio-controllers were detected in tests, showing differentimpact concerning the evaluated pests. This shows that there is a natural pest regulation bynatural enemies, even under the stress conditions to which the agroecosystem is subjected tothe use of agrochemicals. These results establish a basis for future laboratory testing on thesenative bio-controllers to measure their effectiveness for pest control in rice fields.