GLEANINGS IN BEE CULTURE 



.Taxcarv. 1919 



ing it to their hives. Wasps and English 

 sparrows, the real culprits, were not caught 

 at it; hence they go scot-free. Unless our 

 theories will coincide with the facts in a 

 case, they should not be given too much 

 prominence. 



At the annual meeting of the American 

 Association of Economic Entomologists held 

 at Columbus, 0., in December, 1915, Pro- 

 fessor Gossard of the Ohio Experiment Sta- 

 tion gave the results of a series of experi- 

 ments, in which he showed that the germs 

 of fireblight (Bacillus amylovnrus) would 

 remain alive in honey as long as 47 hours, 

 which would give ample time and oppor- 

 tunity for the bees to carry the germs, 

 which they might have attached to their 

 legs or proboscides, to the apple or pear 

 blossoms during their periodical visits. He 

 says: "A fresh culture of B. amylovorns 

 was inoculated into a tube of unsterilized 

 honey and incubated there from 4 to 47 

 hours. At the end of the 4th, 28th, and the 

 47th hours, inoculations were made from 

 the infected honey directly into the tips of 

 apple shoots. These inoculations gave 84, 

 64, and 52 per cent of infection, respective- 

 ly, as against per cent, in the checks kept 

 for comparison. These tests prove conclu- 

 sively to us that the blight organisms, in 

 honey, can remain sufficiently virulent for 

 47 hours to produce infection, with the ex- 

 treme 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 mid- 

 summer, and the results were substantially 

 the same." 



Quoting furthel- from the same article, he 

 says: "It is evident from these results 

 that the formic acid of honey is not imme- 

 diately 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 sur- 

 vive for a time without multiplying, we are 

 unable to reject entirely the possibility of 

 their multiplying 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 we have prov- 

 ed 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 pos- 

 sibility of carrying a considerable fraction 

 of 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 bloom- 

 ing period. However, it must be remem- 

 bered that this surmise, as yet, rests' upon 

 inference alone." 



These results would be very conclusive if 

 it were not for that little word IF. The 

 germs of the disease may be placed in honey 

 and kept alive for some time, but there is 

 no evidence to show that the germs were 

 actually carried into the hive by the bees. 



nor that any were carried out by them on 

 their periodical visits to flowers. It seems 

 to me that one, and perhaps the most impor- 

 tant, point has been overlooked in this dis- 

 cussion, or else the writers have taken it all 

 for granted; and that is, granting that the 

 bees do get the bacillus in honey, or from 

 some other source, and carry it to the flow- 

 ers which they visit, and so inoculate the 

 nectar, how do these germs get into the 

 circulation of the sap? Does the nectar fur- 

 nish a medium in which they will grow and 

 penetrate the epidermal cells, and so get 

 into the circulation, without further assis- 

 tance, or is it necessary for them to be arti- 

 ficially introduced by some foreign agent? 

 Almost every orchardist knows from ex- 

 perience that he can inoculate a healthy 

 branch with the blight virus by the simple 

 prick of a needle which has punctured a 

 diseased branch, but the needle must actu- 

 ally puncture the bark in each case, in order 

 to be effective. Now, the bee, in securing 

 the nectar, does not break the skin or epi- 

 dermis, but simply reaches down and sucks 

 up the nectar. How, then, is it going to 

 introduce the virus into the tissues of the 

 branch, even tho it may have it on its 

 proboscis at the time of visiting the flowers. 

 If, as some authorities have supposed, the 

 nectar is secreted by glands which have no 

 epidermal protection, in other words, which 

 have a direct connection with the tissues 

 and circulation, it is easy to see how the 

 virus might enter the circulation thru the 

 nectar; but, so far as I am able to ascertain, 

 no actual demonstration of that fact has 

 ever been made, and until it is made, there 

 must remain a doubt in the minds of many 

 as to whether the bee is responsible for the 

 trouble or not. In this connection, I quote 

 from an article written by Prof. J. H. Mer- 

 rill, Assistant Entomologist, Kansas Agri- 

 cultural Experiment Station. He states 

 that, "before the blight can be transferred 

 from flower to flower some agency must 

 transfer the bacteria from the canker to the 

 blossom. The bee would take no part in 

 such a distribution as it passes directly from 

 flower to flower without alighting on the 

 branches, and thus it is hard to conceive 

 how the bee could in any possible way trans- 

 mit the bacteria from the canker to the 

 flower." He further states that, "the wind 

 probably plays little or no part in the dis- 

 persion of the bacteria. 



In an article in Science, Nov. 1, 1918, en- 

 titled "Pear Blight Wind Borne," the con- 

 clusion is reached from facts given, "that 

 there must have been some agency of dis- 

 persal other than insects, and that insects 

 were not even of primary importance as car- 

 riers. The only tenable hypothesis is that 

 wind was the chief agent of transmission. ' ' 

 Here we have just the opposite conclusion 

 of that expressed by Professor Merrill. It 

 is evident, therefore, that there is still room 

 for investigation along this line. 



But we all know that the apple aphis, 

 Aphis pomi, makes its appearance quite 

 (Continued on page 60.) 



