GLEANINGS IM BEE CULTURE 



GENERAL CORRESPONDENCE 



IS THE ISLE OF WIGHT DISEASE NEW? 



BY C. E. BARTHOLOMEW, 

 Associate Profes.,^r of Apiculture, Iowa Hiai^ College 



The beekeeper need iic! become paiiiL- 

 stricken when a new(?) bee disease has 

 been discovered. Most new diseases are 

 simply a new name for soj-ietiiiiig' we have 

 always had with us, and tho so-eul'.ed Isle 

 of Wight disease is one of these. This dis- 

 ease has been confused by beekeepers with 

 a great many other common ailments of the 

 honeybee, as the great variety of .symptoms 

 demonstrates. This is due to a great ex- 

 tent to our meager knowledge of actual 

 causes. 



There are at least two and possibly more 

 diseases distinguishable among the many 

 symptoms ascribed to Isle of Wight disease. 

 Bees suffering from paralysis and those suf- 

 fering from dysentery are affected by two 

 distinct diseases, both of which may be 

 present at the same time in the same colo- 

 ny, but not necessarily so. There is present, 

 in all bees examined that had died of malig- 

 nant dysentery, a protozoan parasite that 

 is not nosema, but is a near relative of it. 

 This parasite in all cases was present in 

 large numbers, and infests the digestive 

 tract. In bees dying from the apparent 

 effect of this parasite the alimentary tract 

 was almost destroyed. In fact, it was sim- 

 ply rotten. The nosema is occasionally 

 present in the spore stage in the.se cases, 

 but it is extremely rare. In bees suffering 

 from paralysis the nosema spores are com- 

 mon, and I have found a protozoan present 

 inthe muscles of the honeybee: but whether 

 this is a stage of nosema, Avhieh I am in- 

 clined to believe it is, or some other para- 

 site, I am not prepared to state. The pres- 

 ent status of our knowledge of the life- 

 liistories of these parasites is very meager, 

 and I can only predict that it will be a long 

 time and require considerable study before 

 the end is gained. 



I feel safe in making the statement that 

 malignant dysentery and paralysis are two 

 distinct diseases, and that the malignant 

 dysentery is caused by a protozoan parasite 

 that is not Nosema apis. I call this malig- 

 nant dysentery to distinguish it from the 

 dysentery caused by long confinement and a 

 heavy consumption of stores, and which is 

 not necessarily fatal if the bees have an 

 opportunity for flight. 



The mortality from this dysentery is 

 higher in the spring tha.i any other season 

 of tlie year, and a great deal of spring 

 dwindling is due to it and not to the quality 

 of the stores or many other of the attribut- 

 ed causes. This disease is at its worst at 

 the beginning of brood-rearing in the spring. 

 If tlie colony survives the rearing nf tlie 

 first brood and the appearance of I he new 

 nectar the disease is checked and may not 

 be again apparent until the following 

 spring. When prolonged periods of wet 

 weather reduce the nectar flow and confine 

 the bees to the hive the disease may make 

 its reappearance to such an extent that the 

 beekeeper may notice it. One reason why 

 this parasite is apparently more virulent in 

 the spring is that the longer life of the 

 wintering bees gives a longer developing 

 l^eriod for the parasite, while in the summer 

 the sick bees die in the field while the de- 

 veloping brood make good the losses. 



One of the principal symptoms of this 

 disease is the brown liquid dropping, to- 

 gether with a heavy mortality. When ex- 

 amined under a high-power microscope 

 these droppings will be seen to contain 

 myriads of spores of a protozoan parasite. 



There is nothing to add to the methods of 

 treatment for tliis disease but to caution the 

 beekeeper against leaving the daubed frames 

 and honey for the young healthy bees to 

 clean up, and thus become infected with the 

 para.viie. Remove all daubed frames. These 

 may he washed and returned if not too much 

 soiled, but do not leave it for the bees to do. 

 All ti nces of droppings should be washed 

 from I lie inside and outside of the hive as 

 well a.« from the frames. Thin sugar syrup 

 or thinned honey fed in outside feeders 

 seems I i have some influence in reducing 

 tlie morl ility. 



Ames, Iowa. 



[The \\ I'iter of this article is Associate 

 Professor of Apiculture at the Iowa State 

 College lo( ied at Ames, la. He is, there- 

 fore, proba'iy in possession of a complete 

 equipment for making investigations. — 

 Ed.] 



