February, '16] GOSSARD: blight and BEES 61 



the infected honey directly into the tips of apple shoots. These in- 

 oculations gave 84, 64 and 52 per cent of infection, respectively, as 

 against per cent in the checks kept for comparison. These tests 

 prove conclusively to us that the blight organism, in honey, can remain 

 sufficiently virulent for 47 hours to produce infection, with the extreme 

 time-measure of virulency probably not reached. Tests of this kind 

 were made with fresh apple honey and also with well-ripened honey 

 taken from the hive in midsummer, and the results were substantially 

 the same. 



It is evident from these results that the formic acid of honey is not 

 immediately fatal to the blight organism, and, while we may guess, 

 from the fact that we could get no infection after a certain limit of 

 incubation, that the bacilli simply survive for a time without mul- 

 tiplying, we are unable to entirely reject the possibility of their mul- 

 tiplying in the comparatively raw nectar when it is first carried into 

 the hive and has undergone but little of the curing process. Anyhow, 

 we believe Ave have proved that if one bee carries 100,000 bacilli into 

 the hive one day, that on the following one or two days, each of 1,000 

 bees has the possibility of carrying a considerablefractionof 100 virulent 

 bacilli out to fruit blossoms, because practically all the bees in the hive 

 are at work during the night curing the honey. This would seem to go 

 a long way toward explaining the wholesale infection that occurs in 

 the latter part of the blooming period. However, it must be remem- 

 bered that this surmise, as yet, rests upon inference alone. 



Aphid Honey Dew in Connection with Blight 

 From the similarity in composition of nectar and aphid honey dew, 

 the habit of bees, ants and flies to visit it, and also because of the known 

 relation of aphids to blight inoculation, we were interested to learn if 

 blight bacilli could live for any length of time in this as they do in 

 nectar and in honey. Two of the largest drops we could find on rolled 

 apple leaves on potted trees in the greenhouse were infected with blight 

 bacilh, and at the end of 20| hours, 43 hours, and 71 hours and 20 

 minutes, young apple shoots of potted trees which had always been 

 free from blight were inoculated, using the infected honey dew as the 

 inoculum. These inoculations resulted in 66§, 83| and 100 per cent of 

 infection respectively. 



In each important series of inoculations we made it our practice to 

 reisolate our organism and prove the identity of the bacillus by cul- 

 tures, microscopic examinations and reinoculations. 



The habit of ants to visit colonies of woolly aphids, gathered in the 

 spring around old but living blight cankers, and then of visiting the 

 green aphids on the expanding buds, which are in turn visited by some 



