Pathogenicity in vitro and in semi-field tests of Trichoderma asperellum (Strain VA22) on Aedes (Stegomyia) aegypti (Linnaeus, 1762),in Virginia (Risaralda- Colombia)

“Patogenicidad in vitro y en pruebas de semi-campo de Trichoderma asperellum (CepaVA22) sobre Aedes aegypti en la Virginia (Risaralda- Colombia)”.

Introduction. Aedes aegypti, originally from Africa, has spread globally and is the main vector of dengue in Colombia. The repeated use of insecticides has generated resistan- ce in these mosquitoes, prompting the search for complementary strategies.Objective. This study aimed to evaluate the potential of the fungus Trichoderma asperellum, isolated from the municipality of La Virginia (Risaralda, Colombia), as a biocontrol agent for Ae. aegypti.Methodology. In vitro bioassays were conducted with larvae exposed to a concen- tration of 1x10^8 conidia/mL of the fungus, observing mortality at 24, 48, and 72 hours. Semi-field trials were carried out in the same region, using a concentration of 1x10^7 conidia/mL in containers with Aedes larvae from the area, evaluating larval mortality at 48 hours. To analyze the difference between treated and untreated groups, the Wilcoxon test (P=0.05) was applied using the R program version 4.4.0 (https://www.r-project. org/). Results. T. asperellum showed high pathogenicity, causing 95% and 99% mortality in the in vitro and semi-field tests, respectively. Conclusion. This is the first report of this species infecting immature stages of Ae. aeg ypti in our country. These results suggest that it could be used in Colombia as an alternative to traditional control methods.