84 MASS. EXPERIMENT STATION BULLETIN 234 



Summary 



Bees offered equal parts of honey and the regular spray combination 

 (lead arsenate iVa lbs. to 50 gals., lime-sulfur 1:40, and nicotine sulfate 

 1:1000) were strongly repelled. This combined spray was, however, very 

 toxic to bees and very rapid in its action. 



Lead arsenate spray with honey was readily accepted by the bees. A 

 one-frame nucleus which fed on this mixture lost approximately .50 per 

 cent of its bees within forty-eight hours after feeding. Lead arsenate 

 alone or combined with any of the other materials was very toxic to bees. 



Any mixture containing nicotine sulfate was very repellent to bees and 

 was fed on but sparingly. In laboratory experiments, this repellent action 

 persisted for at least forty-eight hours. In the orchard the period was 

 somewhat shorter, due probably to more rapid volatilization of the nicotine. 



Bees in a nucleus, placed in a greenhouse and offered bloom sprayed 

 with the orchard combination, were at first repelled, but finally worked 

 the flowers and suft'ered a very heavy mortality; indicating that with no 

 unsprayed blossoms available bees will work sprayed bloom. 



In orchard experiments, contrary to what might be expected from the 

 above, neither a late pink nor an early calyx spray, applied when there was 

 considerable bloom on the trees, caused any serious mortality to colonies 

 located in the sprayed orchards. This was due, in the one case, to the 

 fact that the trees came into bloom very quickly after the late pink was 

 applied, thus affording abundance of unsprayed blossoms; and in the other, 

 to the fact that, since bees have a tendency to forage over a considerable 

 area, the repellent action of the early calyx spray caused them to work 

 bloom in nearby orchards. 



In the tent experiments, there was no high mortality except immediately 

 following the application of lead arsenate alone. This was in a measure 

 due to unfavorable weather conditions. It was also due to uneven opening 

 of the bloom. There was always a supply of unpoisoned blossoms avail- 

 able, upon which bees repelled by the combined spray could work. Since 

 lead arsenate was not repellent to the bees, they were not reluctant to work 

 bloom upon which it alone had been sprayed, and consequently were 

 poisoned. 



The experiments indicate that, if the recommended combination of lead 

 arsenate, lime-sulfur and nicotine sulfate is used, spraying should have no 

 appreciable effect upon colonies not subject to any i-estrictions of flight 

 This is true even when some bloom is present, unless improperly timed 

 spraying is carried out on a large scale. 



Publication of this document Approved by the Comjwission on 

 Administration and Finance 



5M. 3-'27. Order 8498. 



