226 REPORT OF THE ASSISTANT HORTICULTURIST OF THE 
The results obtained are somewhat surprising, and much at 
variance with results reported by others. The treatment of saw- 
dust and wheat bran, that has been so confidently recommended, 
proved injurious rather than beneficial, sixty and sixty-one per 
cent, respectively, of the yield of those rows being scabby, while 
the treatment with coal ashes, that is claimed’ to be favorable to 
the production of scab, was equally as efficacious as the sulphur, 
each row producing 18 per cent of the yield that were scabby. 
The row treated with sulphate of copper gave the smallest per 
cent of scabby tubers. This treatment appeared to be the most 
beneficial of any last season,* while the ground bone again was 
detrimental. 
From the results obtained it is evident that little is known 
concerning the true cause of, or remedy for, this disease. <A 
Norwegian botanist claims to have found a slime fungus upon the 
diseased tubers, to which he ascribes the formation of the scab. 
Is THE Potato ScaB CAUSED BY INSECTS? 
For the purpose of securing some reliable data upon this subject, 
several hundred hills of potatoes, in various stages of growth, were 
carefully examined for evidence showing that the scab was due to 
injuries caused by insects feeding upon the tubers. Nothing of 
the kind was found, though millipedes were frequently found 
working in the decaying seed tuber. 
Doubtless the injuries to the tubers caused by tee or their 
larve feeding upon them are often mistaken for the scab, as the 
corky formation that frequently covers the wound appears very 
similar to scab. A careful examination of the two will, in most 
instances, disclose a difference in appearance, the true scab spread- 
ing more upon the surface of the tubers, while that from insect 
injuries is generally limited to a deeper cavity, the edges of which 
end more abruptly. 
On February 14, an experiment was begun in the following 
manner: A glass vessel was partially filled with soil that had 
been passed through a fine sieve, and several dozen millipedes 
(Julus) were placed therein together with several potato tubers, 
one of which had the skin removed from one end so that the 
inner part was exposed. One tuber had received an injury in 
digging, the tine of the digging fork having penetrated it to the 
depth of ayy one inch. 

‘i Report for 1887, page 313, 
