Response of Spodoptera frugiperda (Lepidoptera: Noctuidae) to salt‐stressed maize plants

Salt‐stressed maize is an economically important crop in many arid and semi‐arid regions of the world where soil salinization is most common, and the invasive fall armyworm (FAW) Spodoptera frugiperda threatens global maize production. It thus poses a puzzle of whether FAW populations feeding on salt‐stressed maize plants are becoming more or less invasive. Here, we evaluated the FAW response to salt‐stressed maize plants by examining effects of salt‐stressed maize plants on FAW survival, development and fecundity. We found a longer larval development time (salt‐stressed, 12.9 ± 0.8 d; non‐stressed, 11.3 ± 0.4 d), but unaffected survival rate and pupal mass accumulation in FAW feeding on salt‐stressed maize plants. Moreover, the lifetime egg production of FAW females feeding on salt‐stressed maize plants (633.5 ± 62.7 eggs) was reduced by nearly half compared with those feeding on non‐stressed maize plants (1255.9 ± 70.3 eggs). Overall, FAW showed a negative response to salt‐stressed maize plants. Due to limited population increase potential, FAW populations feeding on salt‐stressed maize plants should pose less of a problem than ones feeding on non‐stressed maize plants do. In practice, salt‐stressed maize plants are quite common in arid and semi‐arid regions where the relatively high‐salinity groundwater is often used to irrigate maize plants, potentially limiting FAW population size. Thus, salt‐stressed maize plants would contribute to practical applications of integrated pest management (IPM) strategies in controlling FAW.