Efficacy of Beauveria bassiana and Mechanical Traps for the Control of Aclees taiwanensis (Coleoptera: Curculionidae) in Fig Plants

The black weevil Aclees taiwanensis Kôno, 1933 (Coleoptera: Curculionidae) is a xylophagous insect native to Southeast Asia and introduced to Italy in 2005. Here, the species completes its entire life cycle on Ficus carica L., causing economic damage and leading to the plants’ death. Nowadays, there are no insecticides registered for its control. In this study, a commercial product based on Beauveria bassiana, Naturalis®, was associated with Rincotrap® tissue. Semi-field trials were carried out on fig seedlings by comparing two different concentrations (3% and 10%) of this entomopathogenic fungus distributed in suspension on Rincotrap® bands. The results showed that the fungal product had a biocidal effect in both treatments. Afterward, trials were conducted in a fig orchard in order to verify the effectiveness of this association in the field. The addition of Naturalis® at a 3% concentration to Rincotrap® bands did not alter the number of adults captured. The total mortality was 43.7% and 23.8%, respectively, in the treated and control plots. Among the total number of dead adults, only the mortality rates of B. bassiana exceeded 70% in both plots. Further long-term studies in several environments are necessary to improve this technique and create an integrated control system for the black fig weevil.