﻿10 BULLETIN 1364, U. S. DEPARTMENT OF AGEICULTUEE 



that the bees still carried an average of 0.0003 milligram of arsenic 

 per bee. The clijfference between these two averages, 0.0002 milli- 

 gram per bee, agrees with the average (0.0002 milligram) removed 

 from the 95 dead bees from the traps by five 'successive washes. 

 Eighty-one pollen carriers, caught and killed in the same manner, 

 were washed five times, and the successive washes analyzed; these 

 contained per bee, in their consecutive order, 0.0003, 0.0001, 0,0002, 

 0.0001, and 0.0001 milligram of arsenic, respectively. 



To trace the arsenic inside the bees, samples were analyzed as fol- 

 lows : Four samples of nectar carriers and one of pollen carriers, 

 not washed, after removal of their honey stomachs and intestines, 

 contained 0.0002 milligram and 0.0011 milligram, respectively, of 

 arsenic per bee. The honey stomachs and intestines of the nectar 

 carriers bore 0.0004 and 0.0005 milligram, respectively, of arsenic 

 per bee. Pollen carriers, washed five times and deprived of their 

 honey stomachs and intestines, averaged 0.0001 milligram of arsenic. 

 Dead bees from the traps, after most of the abdominal contents had 

 been squeezed out, averaged 0.0003 milligram of arsenic, while these 

 contents carried 0.0002 milligram of arsenic per bee. Other dead 

 bees, washed five times and similarly treated, averaged 0.0002 milli- 

 gram of arsenic. 



Two samples each of dead pupee and dead larvae were analyzed, 

 but none of them were found to contain arsenic. 



EFFECT ON HONEYBEES OF SPRAYING FRUIT TREES AT THE 



CUSTOMARY TIME 



The experiments just described, performed at Winthrop, Me., in 

 1914, when the fruit trees were sprayed in full bloom, proved con- 

 clusively that the bees tested had been seriously injured; but since 

 fruit trees are now seldom sprayed in full bloom, this knowledge does 

 not have the economic significance that it would have had when 

 spraying in full bloom was commonly practiced; nevertheless, there 

 are other times, approaching the period of full bloom, when spray 

 materials are commonly applied. In certain regions the time for 

 the so-called pink application is often very short; accordingly some 

 orchardists are still spraying when the blossoms burst open. In 

 other regions the fruit trees of the same variety may bloom irregu- 

 larly, and in still other localities an orchard often contains trees of 

 different varieties, some blooming early and some late. Under such 

 conditions an orchardist when spraying does not usually select the 

 trees to be sj^rayed at the proj^er time, but sprays all as he approaches 

 them, regardless of the age of their blossoms. That bees may be 

 seriously damaged when the trees are sprayed in full bloom strongly 

 indicates that they may also be injured under the conditions just 

 mentioned, and it is furthermore suggested that bees might be 

 slightly injured by spraying at the customary time, when 90 per 

 cent of the petals have fallen. 



To ascertain the effect on bees of spraying fruit trees at the cus- 

 tomary time, the senior writer undertook a research at Roswell, 

 N. Mex., in the spring of 1915, and later in the season repeated the 

 experiments at Benton Harbor, Mich., using the dead-bee traps and 

 analyzing samples of the dead bees collected. In the same season, 

 at Winchester, Va., the junior writer undertook to determine the 



