THE CONTROL OF PLANT DISEASES DUE TO FUNGI. 13 
THE CONTROL OF PLANT DISEASES DUE TO FUNGI 
IN GREAT BRITAIN. 
By A. S. Horne, D.Sc, F.L.S., F.G.S. 
[Read March 7, 1916 ; Sir J. T. D. Llewelyn, V.M.H., in the Chair.] 
Owing to the activities manifested by foreign Powers in the establish- 
ment of phytopathological services prior to the outbreak of war, and 
in view of future relations with other countries and particularly our 
great Dependencies and present Allies, the question of controlling 
the diseases of plants due to fungi is of first importance to 
horticulturists. It deserves and needs very serious attention, but 
before the problem of control can be solved, whether by the in- 
dividual or the State, it is imperative to obtain a thorough know- 
ledge of these diseases. 
The steady progress of mycological work in India during the last 
few years must be attributed to the fact that the tangle of factors 
contributory to first one and then another of the chief plant maladies 
of India was first skilfully unravelled, and then, after a careful survey 
of the position, a practical method of control was speedily devised. 
Nowhere is this more evident than in Butler's study of the bud-rot 
of Palms. Here the method and rate of spread of the trouble, the 
relation to rainfall and the monsoons &c, the symptoms of the disease 
and habits of the parasite (Pythium palmivorum) are thoroughly 
considered, and as a result suggestions for an organized attempt to 
stamp out the disease in the infected area were made to the Govern- 
ment of Madras in 1906, and the sum of 5,000 rupees was provided 
for a trial in a limited area ; larger proposals were given effect to in 
the following year, and led to a great campaign which dealt 
systematically with every part of the whole infected area. Again, 
Butler and Hafiz in 1913, by discovering infection in apparently 
sound setts, were able to show in red rot of the sugar-cane why sett 
selection, the most hopeful method of checking the disease, had 
hitherto failed. 
In these Indian studies it proved essential to understand the 
parasite and its habits in both active and passive forms, its methods 
of sporulation, and distributive and infective powers. I will now give 
some additional examples to show how mere cultural work with fungi 
may elucidate points of practical importance. Everyone knows the 
common fruit-rot fungus, Monilia fructigena, but it is from Norton 
we learn that this fungus is an ascomycete : the ascigerous stage, 
Sclerotinia, according to Whetzel, can bring about a shot-hole effect 
in leaves of the Cherry and Peach. Again, Sphaeropsis Malorum 
