Interactions
The following eat or destroy the Horseradish root:
Cabbage aphid ,Turnip aphid, Cutworms, Diamondback moth, Imported cabbage worm, Cabbage flea beetle, Wireworms
The most damaging is the Cabbage flea beetle which is a small,
shiny, steel-blue jumping beetle that attacks young foliage and may
require control measures to stop it. The Wireworm burrows into the
root to grow, damaging it.
1911 Encyclopędia Britannica/Economic Entomology
Horseradish is a good companion plant for potatoes since it is said to deter potato eelworm and the Colorado beetle. One plant at each corner of the potato patch is sufficient enough for most gardens. When grown under apple trees it is said to prevent brown rot, powdery mildew and other fungal diseases.
The most obvious interaction is with humans to make horseradish sauce, continue reading to learn more.