There's a good article in the new Northeastern IMP Center Insights newsletter about using guardian plants for pest control in greenhouses. The example they use is eggplants for whitefly; the eggplants draw the whitefly away from the greenhouse crops (e.g. poinsettias), plus provide a good place for the whitefly's natural predator, a parasitic wasp, to live. If there are still too many whitefly, major chunks of the population can be controlled just by targeting the guardian plants—the whole greenhouse doesn't have to be sprayed.
IPM Insights - Guardian Plants in Greenhouses
Animal Tracking School
11 hours ago