107 



FOOT ROT. 



This Diseases is also known as "Collar Rot" and "Mai di Gomma.' r 



The English names refer to the place in the tree attacked, — the 

 lower portion of the stem next the ground, and the upper portion of 

 the root just below the surface. The Italian name refers to the for- 

 mation of gum which is the usual accompaniment of the disease. 



Ihe bark decays at the collar, gumming takes place with a disa- 

 greable odour, the leaves look unhealthy, and of a sickly, yellow colour, 

 the small shoots die off, and the fruit sets abnormally thick. The 

 decay of the bark extends to the main roots and round the stem ; this 

 process is assisted by the attacks of ants. When it has completely 

 girdled the tree, death follows. 



There are several conditions which may be considered as rendering 

 the tree liable to "foot rot," but the disease itself is supposed to be a 

 minute fungus. 



Observation has shown that the disease is most common where any 

 of the following conditions exist : Improper drainage ; planting the 

 trees so close together that the ground is continually shaded and kept 

 moist ; continuous use of organic fertilisers ; excessive cultivation ; 

 continuous excessive irrigation which keeps the soil water-soaked ; and 

 deep planting. 



Ihe manner in which the disease spreads, appearing at different 

 dates first in one country and then in another, and extending gradually 

 from grove to grove, strongly indicates that it is contagious, being 

 caused or at least greatly aggravated by some parasitic organism. It 

 is thought by many to result from the attacks of some parasitic orga- 

 nism, and Professor Briosi describes and names a fungus Fusisporium 

 limoni which he finds always accompanying the disease. He is in- 

 clined to consider the fungus the cause of the trouble, but is in doubt 

 as to whether it is the primary cause. He says, however : " I do not 

 believe there can be any doubt to at its presence accelerates the disor- 

 ganization of the tissues and aids in extending the disease." 



The following letter shows that the disease can be combated with 

 success. 



Hon. Oscar Marescaux to Director, Public Gardens and Plantations. 



Cherry Garden, Jamaica, 

 20th May, 1901. 



Dear Mr. Fawcett, 

 Some time ago in reply to my enquiry you were good enough to 

 give me the following receipt for keeping off the black ants from eating 

 the peel of my orange trees just where they come out of the ground : — 

 2 lbs. common clay dissolved in w T ater to the consistency of or- 

 dinary paint, 

 2 lbs. flour of brimstone properly mixed in same, 

 A small piece (say a good table-spoonful) of Soft Soap, 

 A couple of spoonfuls of ordinary kerosine oil — 



to be applied with a brush at the foot of the tree. 

 Besides using this mixture for the above purpose, I have caused 

 some of my trees which were covered witii the white scale to be painted 



