The pathogenicity assessment of five entomopathogenic fungi (EPF)-based products against C. orchidii pupal stages resulted in the selection of an effective one that was evaluated in dose–response studies by immersion and soil application. With the concentrations obtained from these experiments, we observed reduced C. orchidii emergence in the field when the selected EPF product was applied to irrigated areas during the summer. • The B. bassiana -based products were highly effective against C. orchidii pupae. • C. orchidii pupates near the soil surface, suitable for EPF application via spray. • Soil–targeted EPF applications effectively reduced C. orchidii field densities. Chaetanaphothrips orchidii (Moulton) is a tropical thrips that affects a wide range of crops, including Spanish citrus, since 2016. Currently, its management is based on preventative applications of synthetic insecticides to the tree canopy. As this species is known to pupate in moist soil, targeted application of entomopathogenic fungi (EPF) might be a more sustainable management alternative. We conducted an initial screening of EPF formulations to select the most efficacious candidate. Subsequent virulence bioassays quantified the operational dose required to achieve field–relevant mortality. Moreover, the pupation depth of C. orchidii was determined to inform the subsequent field trial. The initial EPF product screening showed an efficacy of all products of at least 64%, with three exceeding 95% at six days post-inoculation. The selected product displayed an LC 90 of 1.64 × 10 7 CFU/ml by pupal immersion and 75% efficacy at a concentration of 1 × 10 8 CFU/g in treated soil. Additionally, it was determined that in high soil moisture levels, C. orchidii mostly pupates in the top 2.5 cm of soil, indicating that surface soil applications could be effective. Results of the field trial showed that C. orchidii density decreased significantly when the EPF product was applied to the soil near irrigation emitters during the summer. Our study highlights that drip-irrigated high-moisture areas are key intervention points for deploying EPF in IPM strategies against C. orchidii in citrus orchards.
Juncá-Morales et al. (Fri,) studied this question.