XXIV. 
EEPOET OX DISEASES OF PLANTS IN HEETFORDSHIEE IN 1890. 
By A. T. Brett, M.D. 
Mead at Watford, 13 th April, 1891. 
"When, last April, I invited our Society to study the injuries to 
and diseases of plants, I thought I might be poaching on the 
domains of our recorder of injurious insects; but, although many 
diseases are caused by insects, others are caused by fungi, and it is 
to such that I wish particularly to direct attention. 
Two diseases due to fungi were very prevalent in Hertfordshire 
and elsewhere last year. I allude to the disease called “ club ” in 
cabbage and “ aubury ” or “ finger-and-toe ” in turnips, and to the 
potato disease. The former is caused by the slime-fungus, Plasmo- 
diophora brassicce, and the latter by the fungus known as Perono- 
spora infestans. 
A farmer near Watford had a large field of turnips nearly 
destroyed by the slime-fungus. I took some specimens to Miss 
E. A. Ormerod, and she informed me that gas-lime was a sovereign 
remedy for this disease. When residing at Isle worth she cured 
“ club” in the cabbage roots in her garden by its application, the 
roots having previously looked like tuberculated maces. The 
knowledge of the great utility of gas-lime had spread to such an 
extent that while it could be had for the carting when she went to 
Isleworth in 1874, when she removed to St. Albans, in 1888, it 
was charged 7s. the cart-load, and she thought it wonld be a real 
boon to farmers generally to know how useful gas-lime is, and 
precisely how it acts. 
The potato disease appears to be disseminated in great measure 
by carelessness and want of knowledge of the necessity of killing 
the spores of the fungus which causes it. On these points Mr. 
J. W. Odell, of Stanmore, who has devoted considerable attention 
to the subject, says: ‘‘Gardeners and farmers are heavily handi¬ 
capped in their attempts to keep the disease under by the thought¬ 
less practice of those people who take no steps to kill the spores. 
I have seen this season, on cottagers’ gardens, the haulms and 
diseased tubers lying about, in this state, tainting the whole 
neighbourhood with the conidia, the slightest puff of wind being 
sufficient to send off the germs in all directions. This is, in my 
opinion, a criminal practice, and should be stopped by the law. 
Another practice is to give pigs the tubers when they are in an 
advanced stage of disease, the spores being by this means distributed 
throughout the manure-heap ready to be again committed to the 
garden for further development. It cannot be too strongly urged 
upon potato growers that it is madness on their part to allow either 
tops or tubers to remain undestroyed. They should either be 
burned or buried in quick-lime, the former method being the best. 
Land upon which diseased potatoes have been grown should be 
subjected to a good dressing of hot lime, and then thrown up rough 
