Apr. 21,1923 
Gummosis of Citrus 
193 
The disease advanced rapidly from Messina, passing into the province 
of Catania to Acireale. In 1865 it was established at Palermo, raging 
severely there until 1870. In all the Sicilian Citrus orchards the gum¬ 
mosis was present in such intensity as to constitute a true epidemic which 
destroyed all the trees. The orchards were later replanted with sour- 
orange stocks. In 1870 the disease was established in the region of 
Genoa. It became scattered (not epidemic) in the orchards of the 
Naples, Amalfi, and Gargano regions. Briosi {ii) estimates the damage 
from gummosis in Italy as $2,000,000 from 1862 to 1878. 
In Greece, in Tunis, and in Spain gummosis became distributed in 
varying degrees of intensity. Briosi refers to its destructiveness in the 
Balearic Islands (near Spain) in 1871. In more recent years a similar 
disease has been reported in the Oasis of Tripoli by Leone (4^) in 1918. 
Gummosis was attracting attention in Cape Colony, South Africa, in 
1891. 
In Australia a destructive gummosis is referred to by Alderton (j) as 
occurring in New South Wales between i860 and 1870, by McAlpine {46) 
as occurring near Sydney in 1867 and in Queensland in 1876. It is 
reported by Kirk {43) in New Zealand in 1885. 
In the United States, records place its appearance at about the year 
1875 in California according to Mills {48) and 1876 in Florida by Curtiss 
{if). In Florida, as footrot or mal di gomma, it attracted serious atten¬ 
tion in 1879, following a very wet year according to Hume {41), Moore 
(49, p, 128-132), in 1881, speaks of its recent appearance, and Swingle 
and Webber {64) in 1896 report it as still gradually spreading. In 
California, gummosis was a serious trouble in nearly every Citrus locality 
by 1878. It was spoken of by Garey {34, p. 81-82) as the only Citrus 
disease of importance at that time. The horticultural literature of this 
period indicates that the discontinuance of the use of the common lemon, 
lime, and citron as stocks and the general adoption of the sour orange and 
sweet orange as the principal stocks in California were due to this disease. 
Some of the other localities in the American continents where gum¬ 
mosis has been an important disease are reported in Paraguay by Bertoni 
(p), in Brazil by Avema-Sacca (5), in Mexico by Gandara {33), in Cuba 
by Cook (15) and Cook and Home {16, p, 55), and in Porto Rico by 
Stevenson {62), 
Viewing the history of Citrus gummosis from the investigational 
standpoint, Briosi {ii) studied a gummosis (mal di gomma) in Italy and 
described a fungus, Fusarium limoni Briosi, which he considered to be a 
factor in the development of the disease. McAlpine {46) regarded a 
similar type of severe gummosis in Australia as undoubtedly of an infec¬ 
tious nature and referred to the same fungus as the causal agent. His 
description of the disease indicates that it is similar in character to the 
form which Pythiacystis gummosis takes on large orange trees in Califor¬ 
nia. It is quite possible that the “slender wandering filaments** which 
he found penetrating the tissue may have been those of a Pythiacystis- 
like fungus. In this connection it is of interest to note that in a letter 
to the writer in February, 1917, G. P. Damell-Smith of the Department 
of Agriculture, New South Wales, reports finding Pythiacystis citro- 
phthora on specimens of Citrus affected with a gum disease sent from the 
Norfolk Islands, east of Australia. Later, F. Stoward, in a letter of 
October 1917, reports having isolated P, citrophthora from lemon fruits in 
Western Australia and having confirmed its pathogenicity by inocula¬ 
tion. 
