Impact of intercropping soybean with buckwheat on key soybean pests and beneficial insects

Intercropping has gained increasing attention as a sustainable agricultural practice that enhances crop performance while reducing reliance on chemical inputs. The effect of intercropping for integrated pest management was evaluated by combining soybean (Glycine max L.) with buckwheat (Fagopyrum esculentum Moench) across three study areas in northern Italy: Chioggia, Vigonovo, and the Agripolis experimental farm. The effects of intercropping were assessed on populations of the two-spotted spider mite (Tetranychus urticae Koch) and the brown marmorated stink bug (Halyomorpha halys Stål), two economically relevant soybean pests, as well as on pollinator activity and diversity. At the Toniolo experimental farm, different intercropping configurations were tested in a randomized block design to identify the most effective arrangement for pest management (2:1, 1:1, frame, pure crop); additionally, the efficacy of Phytoseiulus persimilis as a biocontrol agent against T. urticae was assessed. Using sentinel egg masses, the study also investigates the abundance and diversity of stink bug parasitoids and naturally occurring predatory mites associated with T. urticae. Field trials compared monocropped soybean with soybean–buckwheat intercrops, assessing the potential of buckwheat as an ecological service crop that supports both pest suppression and beneficial insect communities. Overall, intercropping soybean with buckwheat resulted in lower H. halys infestation levels at both the Toniolo experimental farm and in Chioggia. Regarding T. urticae, 2:1 and pure soybean exhibited the lowest levels of infestation. In Chioggia, the presence of buckwheat significantly reduced T. urticae infestation. Results concerning the abundance and diversity of the pollinators community were not significant. The present study highlighted some positive outcomes of intercropping in reducing pest pressure in soybean fields.