58 
Bee Disease 
I hree .stocks of bees, one Italian, one Carniolan and one black (British or 
Dutch?) were imported into the apiary from Devonshire on June 4th, 1915. 
During June these three stocks gave off four swarms and the seven colonies 
were showing crawling symptoms on June 30th. Three of the colonies died 
o\\ mg to faulty cpieens and another was destroyed by robber bees. A fifth was 
reinforced by the addition of three pounds of bees (source not stated) and an 
Italian queen was also given to this colony. Some driven bees from Wales 
were placed in the apiary. In December, 1915, there were four stocks alive 
showing no signs of disease. 
Accounts of further work by Dr Rennie and Miss Harvey (1919 a and b) 
arc given in the Journal oj the Scottish Board of Agriculture. With regard to 
A osema the conclusion arrived at is that it "is always a weakening factor, 
and in the presence of other adverse conditions favourable to the development 
of dysentery it may become seriously pathogenic to bee stocks.” in ordinary 
circumstances it v r as not found to destroy colonies in the rapid and virulent 
manner generally found in Isle of Wight disease. The authors consider that 
in the latter disease there is no recovery of sick bees nor of affected stocks. 
Mention is also made of a temporary sickness wdiich sometimes affected 
all the bees of a district. ‘'In such cases it would appear to be due to some 
disturbing factor in the nectar or pollen.” 
C. Acarapis (Tarsonemus) woodi. 
In November, 1920, a paper was read before the Royal Society of Edin¬ 
burgh in which Dr Rennie, in association with Mr Bruce White and Miss 
Harvey, described a new species of mite from the tracheae of hive bees. This 
mite, which was named Tarsonemus ivoodi, was put forward as being the cause 
of Isle of Wight disease, which was henceforth to be known as “acarine 
disease.” Hirst (1921) considers that the new mite differs sufficiently from 
Tarsonemus to form a new genus and proposes that the species shall be 
renamed Acarajns woodi. 
The mites gain entrance to the tracheae by means of the first pair of 
thoracic spiracles. Crawling of bees, followed by the death of the affected 
colony then takes place. The presence of the mite is not necessarily fatal 
however, for we read in the Report to the Royal Society of Edinburgh that 
Of 140 stocks believed by their owners to be healthy, 50 or nearly 30 per cent, har¬ 
boured the parasite. Concurrent with such discoveries we ascertained by direct examination 
ourselves of flying bees (1) which were members of colonies in which the disease was definitely 
established and (2) which were taken from colonies believed to be healthy and showing no 
indications otherwise, that amongst these were to be found considerable numbers harbouring 
the parasite. This was further complicated by the fact that in those infected flying bees 
certain of those pathological conditions— e.g. the blackening and hardening of the tracheal 
tubes—were very marked. As an example it may be quoted that this condition was found 
in bees entering the hive carrying pollen or nectar, both belonging to stocks in which 
crawling and other symptoms were well established and also in those reputed healthy 
stocks. 
