Fruit Trees - Horse radish planted at the base of smaller fruit trees serves not only as an insect repellent , but it is believed to also deter birds from picking at the fruits and berries. It will deter small rodents such as moles and field mice , however squirrels do not seem to be bothered by it. Horseradish deters weevils and beetles such as "curculios" which feeds on the produce of plum trees.
Beans - there is no documentation that I know of regarding planting horseradish with beans. However based on personal observation and speculation I would advise against it. I've tried it several times in the past with different varieties of beans and legumes and was not happy with the results. The beans, in my opinion , did not fare as well as others planted away from the horse radish. Of course thare are many other possible variables that could have been responsible. But there are also many other companion plants available where as you don't have to waste your bean plants in experimentation.
Detoxification and Anti-fungal properties
Recent advances in the research of plant-derived anti-fungal compounds
Penn State Horse Radish Bioremediation Results
Penn States experimentation lends credence to what many organic gardeners already knew/believed. That is that horseradish has anti-fungal properties, not only in a concentrated form , but also when grown directly in the soil.
You can also create a simple horse radish tea as a preventative anti-fungal spray. The horse radish spray has proven effective against against brown rot in apple trees and other fruits. Process horseradish roots in a food processor till a coarse paste is achieved. Dilute the paste with 1 part horseradish paste to four parts water and let is sit 24 hours. Strain off the liquid, discard the pulp, mix the liquid with a quart of water and a half cup of vinegar and you have a viable spray. This tea also serves as an effective bug spray for plants.