Grapevine Responses to the Entomopathogenic Fungi and and the Effects of Salicylic Acid on Their Virulence Against the European Grapevine Moth, .

Entomopathogenic fungi (EPF) are substantial biocontrol agents reducing the populations of economically important pests in numerous crops. Recent findings indicate that their role in agroecosystems is more complex and extends to affecting plant physiology and growth. This study examined the effects of and , as well as Salicylic acid (SA), on physiological parameters of grapevine ( cv. Sauvignon Blanc). Additionally, the impact of SA on spore germination and pathogenicity of EPF against larvae of the European grapevine moth () was tested. Foliar application of EPF was found to increase the electron transport rate (ETR) from PSII to PSI, indicating higher photosynthetic activity compared to control plants. EPF also elevated the transpiration rate (E) and stomatal conductance (gs). In contrast, SA treatments decreased E and gs, while the high dose (10 mM) exhibited reduced Fv/Fm value, accompanied by phytotoxic spots on leaves. Spore germination of both fungi was significantly reduced only by the SA concentration of 2 mM, while 0.5 and 1 mM did not affect germination. Combination EPF and SA treatments presented the highest larval mortality of (87.5% at 28 °C and 77.5% at 24 °C for and , respectively). However, SA reduced larval mycosis in most cases. Overall, the results suggest that EPF and SA can be co-applied and included in vineyard integrated strategies to support grapevine health.