Polyculture Pest-Suppression Simulator

Plant a field of a single crop, or the same amount of that crop interspersed among other companion crops, then release a specialist pest and watch how far it spreads. In the monoculture field every plant is a suitable host, so the pest radiates outward efficiently and damage climbs fast and uniformly. In the polyculture field the same pest, released under identical conditions, keeps running into non-host plants that it cannot use — its spread stalls into slow, patchy pockets and far less of the target crop is lost, purely from the planting arrangement, with no pesticide involved.