44 



fumigation the treatment should be made some time between 

 December and the first of March. During this period the 

 temperature is usually much lower than at any other time, and 

 this is a feature of importance. In treating this disease, it has 

 been found more effective, to allow the gas to act for a slightly 

 longer period than usual, say about forty minutes. 



A parasitic fungus (Aschersonia tahitensis), has been found 

 which attacks and destroys the larvae and pupae of the mealy 

 wing, and bids fair to be of great aid in combating this pest. 

 It forms small wart- like conical pustules, from 2. to 3 mm. in 

 diameter. At first these are white or orange yellow through- 

 out, but in the mature stage the spore masses become orange 

 red. This fungus is frequently found in groves affected with 

 sooty mould. It dots the under surface of the leaves, and may 

 occasion alarm if its nature is not understood. Unless 

 examined in an early stage of development, no trace of the 

 mealy wing scale can be discovered without microscopic study. 



When sooty mould follows attacks of the wax scale, mealy 

 bug, or orange aphis, thorough spraying with the resin wash 

 or standard kerosene emulsion will be found effective. The 

 time when the treatment should be made is not important in 

 these cases, but if the resin wash is used, a dry season should 

 be selected when the work will not be rendered uncertain by 

 the liability of rainfall. 



FOOT-ROT MAL-DI-GOMMA (5). 



Foot-rot or mal-di-gomma is a disease chiefly of the orange 

 and lemon, and is probably more widespread than any other 

 citrus malady. It is known to occur in almost all countries 

 where the orange is cultivated, but so far as known appeared 

 first in the Azores Islands, where it was very severe. Accord- 

 ing to the statement of Fouque (6), it was first noticed in this 

 group in 1834, on the island of San Miguel, where it seems to 

 have originated. From that time till 1840, he estimates that 

 fully one fourth of the trees were destroyed. It reached its 

 greatest severity on the island in 1840 ; in 1842, it had begun 

 to decrease, and in 1873 it had ceased to be very serious. F. 

 Alphonso says (7) that according to general report the malady 



(5) An account of this disease prepared by B. T. Galloway was pub- 

 lished in Part II, of Bulletin No. 8 of the Division of Botany, U.S. 

 Department of Agriculture. 



(6) Voyages geologiques aux A cores, III., Les Cultures de S. Miguel 

 (Eevues des Deux Mondes, Paris, Apr. 15, 1873, p. 837). 



(7) Alphonso, F., La coltivazione degli aranci nelle Azzorre, (Annali 

 di agricoltura Siciliana, Vol. V., 1873, p. 311). 



