THE POISONING OF HONEY BEES BY ORCHARD SPRAYS 



By A. I. Bourne 



The importance of honey bees in the pollination of blossoms, thus insuring 

 the set and yield of fruit, has long been recognized by orchardists, many of 

 whom own colonies of their own or rent them from neighboring beekeepers 

 during the blossoming period. The question, therefore, "Does spraying 

 orchards kill bees?" has been one of vital interest to both fruit growers and 

 beekeepers ever since the use of poison sprays to combat orchard pests has 

 become general. It has been the subject of a great deal of discussion and, 

 undoubtedly, led to considerable ill feeling, yet comparatively little has been 

 done in the way of actual experiments. 



Years ago, before insecticides or methods of using them had become stand- 

 ardized or any well defined spray schedule developed, growers attempting to 

 control their numerous pests undoubtedly did much spraying which was ill 

 timed and dangerous to bees. An investigation was begun by the Station in 

 1922 to determine whether present day practices, using the common spray 

 combinations according to the schedule now recommended, would cause any 

 serious mortality to bees. The work was carried out in cooperation with 

 Professor N. E. Phillips and, later. Professor M. H. Cassidy who had in 

 charge the care and manipulation of the colonies and who made the observa- 

 tions on the behavior of the bees during the experiment. 



Laboratory Experiments. 



Behavior of bees fed on the common spray mixUire. 



Preliminary studies were made in the laboratory to determine whether 

 bees were attracted or repelled by the combined spray of lead arsenate, 

 lime-sulfur and nicotine sulfate; whether this combination if fed upon by 

 bees would prove fatal; and what the symptoms of poisoning were. 



A single frame nucleus, without stores, in an observation hive was fed a 

 mixture of honey and the three insecticides diluted as for orchard spray- 

 ing, and the reaction of the bees was noted. The temperature during the 

 experiment was kept about 60°F., a temperature at which bees feed read- 

 ily, yet do not become too active within the confined space. 



For several days after being transferred, the bees were fed a dilute honey 

 solution, which they readily accepted. During this period the number of 

 bees that died each day was recorded, to determine the normal daily mor- 

 tality. The bees were then oflFered a mixture of equal parts of honey and 

 the spray combination. They were very strongly repelled by this mixture 

 and only one or two were observed to feed upon it at all. The bees even 

 showed a strong tendency to move away from that part of the comb near 

 the feeder. The few bees which had taken some of the mixture were taken 

 out of the hive and isolated to note their reaction. All of them showed 

 symptoms of poisoning and died within twenty-four hours. 



