Native entomopathogenic fungi as potential biocontrol agents against Tetranychus urticae in strawberry cultivation

The two-spotted spider mite, Tetranychus urticae , is a major constraint in strawberry production, and its management still relies heavily on acaricides. This study aimed to select native entomopathogenic fungi with biocontrol activity against T. urticae in strawberry cultivation through field sampling, laboratory bioassays, and greenhouse validation. The mite was detected in all eight farms evaluated, which had been selected based on previous infestations of the pest, including apparently healthy plants, where infestation incidence ranged from 10 to 100%; in symptomatic plants, incidence varied from 40 to 100%. Among the seven fungal isolates evaluated at a concentration of 1 × 10 8 conidia mL - ¹, HF234, identified as Metarhizium anisopliae ., produced the highest corrected mortality in adult females (84.3 ± 8.9%), followed by HF188 (74.2 ± 3.5%) and HF232 (73.7 ± 5.8%). In the direct comparison between fungal and chemical treatment, HF234 produced significantly higher corrected mortality than abamectin (84.31 ± 2.06% vs. 68.14 ± 2.98%). Under greenhouse conditions, HF234 significantly reduced the abundance of eggs, larvae, nymphs, and adults compared with the negative control (p < 0.001). HF234 also resulted in significantly lower abundances of eggs, larvae, and nymphs than abamectin, whereas adult abundance did not differ significantly between the two treatments. These findings indicate that early and concealed infestations can occur in strawberry crops and identify HF234 as a promising native biocontrol candidate for the management of T. urticae . Further evaluation under field conditions is required to determine its potential for integration into sustainable pest management strategies.