Mycorrhizal inoculum–mediated modulation of maize–rhizosphere interactions under pesticide stress

Arbuscular Mycorrhizal Fungi (AMF) and synthetic pesticides are frequently applied together in conventional agriculture, yet their interactive effects remain largely understudied. This gap limits our understanding of whether co-application leads to synergistic benefits or unintended antagonistic impacts on soil function and plant performance. This study evaluated the effects of the co-application of a Funneliformis mosseae inoculum together with three commonly used pesticides - fungicide pyraclostrobin, and the herbicides tembotrione, and clopyralid - on the growth of maize ( Zea mays ) plants, AMF colonization levels and AMF community composition under controlled greenhouse conditions. Using a full-factorial design, we assessed whether the AMF inoculum could buffer pesticide-induced disruptions in plant and fungal growth parameters and soil functions. The F. mosseae inoculum did not consistently mitigate pesticide stress on plant performance but significantly enhanced pesticide dissipation and modulated rhizosphere phosphatase activity. Amplicon sequencing revealed that the inoculum shaped AMF community composition, promoting resilience in the rhizosphere. Root-associated communities remained more vulnerable to chemical disturbance. These findings highlight that while AMF can influence pesticide fate and AMF diversity, their capacity to buffer against pesticide impacts on plant performance is limited and strongly context dependent. This underscores the need to tailor the use of biostimulants to specific chemical regimes, when aiming to improve soil resilience and crop productivity in intensively managed systems.