It is effective against certain true bug pests in the Hemiptera family and is highly toxic to honey bees. It is particularly effective against leaf-feeding beetles and certain caterpillar pests. Rotenone is a powerful inhibitor of cellular respiration, the process of converting cell nutrients into energy. It acts primarily in insects nerve and muscle cells, causing them to stop feeding quickly. Death occurs several hours to a few days later.
Rotenone is extremely poisonous to fish.
Mammals detoxify ingested rotenone with enzymes found in the liver, but it can be quite toxic when inhaled. It is one of the more toxic of the botanicals. This is the powdered stems and roots of a South American plant, Ryania speciosa. Reported to be most effective in hot weather, ryania has longer residual activity than most other botanicals. Ryania is moderately toxic to mammals by ingestion and only slightly toxic by skin exposure.