DISEASES DUE TO BACTERIA 133 
mentioned plants and “stripe” disease of the tomato 
are caused by the same organism is of considerable 
importance to commercial growers. It is now possible 
to explain why certain nurseries have been badly attacked 
by “stripe” in the first year of their existence—a fact 
which has hitherto been inexplicable. It is highly 
probable that the land had previously held a leguminous 
flora suffering from “streak” disease which had been 
overlooked. Already we have proved this to be true in 
a number of nurseries where “stripe”? has just started. 
The previous diseased crop was clover in three cases and 
vetches in two. It is advisable, therefore, when choosing 
a site for a new nursery, to have the advice of a plant 
pathologist to ascertain if the existing crop is free from 
““ streak” disease. 
Control.—As the disease is intimately connected with 
soft, rapid growth, induced by an excess of nitrogen and 
a deficiency of potash in the soil, manuring with the 
latter has proved an efficient method of combat- 
ing it. 
Affected plants will grow away clean if top-dressed 
with sulphate of potash. A suitable dressing is five 
hundredweights to the acre which in severe cases may be 
repeated after an interval of a month to six weeks. 
Generally the most convenient method of treatment is 
to dissolve half a pound of sulphate of potash in fifty 
gallons of water, and apply the solution at the rate of a 
pint per plant to the diseased plants each week until 
they show a clean new growth. The cutting away of a 
diseased stem and allowing a lateral to develop will 
often give a clean plant. As the disease is spread from 
plant to plant by means of the pruning knife, workers 
should be taught to leave the diseased plants until 
all the healthy ones have been attended to, and 
before passing to a healthy plant, after pruning a 
diseased one, the knife should be cleaned by wiping the 
blade with a rag soaked in two per cent lysol or other 
disinfectant. 
