During the past few years considerable evidence has accumulated indicating that plant poisoning causes heavy losses of bees in this country. A few of the plants that cause poisoning of bees have been circumstantially or positively identified and it appears that several other such plants exist. It seems important to obtain as much information as possible regarding plant poisoning of bees, in order to distinguish it from diseases and other bee disorders and provide information that may help in reducing the heavy sporadic losses. Since the cases are often of short duration and occur in widely separated sections of the country, it has thus far been possible to study only a few of these on the ground. A particularly interesting phase of plant poisoning of bees is the extremely specific action of the toxic substances from different plants. In some cases only the field bees are killed. In other cases losses have been limited largely to recently emerged bees, to sealed brood, or to unsealed brood. In some cases both the adult bees and brood appear to be affected by poisons from the same plant. In no case where plant poisoning has caused loss of bees or brood have human beings been adversely affected by eating the honey.
Burnside, C. E. and Vansell, G. H., "Plant Poisoning of Bees" (1936). Bu. Paper 36.
Available for download on Saturday, January 01, 2050