DETECTION OF Wolbachia IN NATIVE POPULATIONS OF THE GRAPEVINE MOTH (Lobesia botrana), IMPLICATIONS FOR ITS CONTROL

ESTESO C; DÍAZ NIETO LM

Encuentro; XLI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2024

The grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), is a polyphagous insect, considered the most important pest of vineyardsworldwide. Given the impact of this pest in Argentina, a phytosanitary emergency was declared by SENASA in 2021. To reduce the damagecaused by the pest, chemical insecticides for immature stages and the sexual confusion technique for adults are used by control programs.Currently, several approaches are being studied for biological control, including natural enemies, microorganisms such as entomopathogenicfungi and Bacillus thuringiensis (Bacillales:Bacillaceae). In this context, the obligate intracellular bacteria Wolbachia can induce reproductivechanges in insect hosts through male killing, feminization, parthenogenesis or cytoplasmic incompatibility. Wolbachia can also influenceinsects to reduce susceptibility to entomopathogenic bacteria and pesticide sensitivity. For L. botrana, Wolbachia infection has only beenreported in native populations of Portugal. To develop control strategies based on this bacterium, the first step is to determine whether thetarget pest population is naturally infected with Wolbachia or not. The aim of this study was to evaluate Wolbachia infection in native L.botrana populations from different winegrowing area of San Juan, Argentina. L. botrana were captured from five vineyards usingcommercially available sticky traps with specific pheromones (BioLureR). The presence of Wolbachia was analyzed on the basis of 20individuals per collection site using wsp gene-specific PCR. Amplification of the 16S rDNA gene was used as a control. PCR-amplified DNAfragments were sequenced by an external service of Macrogen Korea. Sequences were manually edited, analyzed with BLASTn and alignedwith MEGA v.11. All populations tested were positive for Wolbachia,representing the first record of Wolbachia strains in grapevine mothfrom Argentina. The infection rate varied among the different locations: 20/20 in Las Chacritas, 14/20 in La Puntilla, 19/20 in 9 de Julio,Ullum 17/20, and 16/20 in Paso del Algarrobo. Sequences obtained from the populations in San Juan are similar to each other (100% identity),and at the same time they are similar (99% identity) to those from Portugal. Our results could rule out some possible phenotypes caused byWolbachia in the studied populations: 1) the fact that the individuals analyzed were only males would exclude the possibility of theparthenogenesis, feminization or male killing phenotypes, 2) the presence of Wolbachia in all populations analyzed plus the advance of L.botrana in the region, would exclude the possibility of finding strains of cytoplasmic incompatibility or it could also be thought, that theyhave already replaced the non-carrying wild populations. Further investigations are needed to fully explore the relationship betweengrapevine moth and Wolbachia, in this way, propose the development of the pest management strategies based on such symbiosis. Moresequences available in databases are needed to determine the relationship between strains from different regions.