jan.a 7 ,1923 Production of Conidia in Philippine Sclerosporas 271 
such distant maize-growing countries as the United States, however, 
must necessarily be continuous. 
The Philippine Sclerosporas can be disseminated in three different 
stages in their development, as mycelium, as resting spores (oospores 
with adherent oospore wall), and as conidia. Each of these demands 
consideration in its relation to the various phases of local and of distant 
spread in the Philippines or to remote countries. 
DISSEMINATION BY MEANS OF MYCEUUM 
Mycelium, from its very nature can not be distributed by itself but 
must be carried with some part of the plant such as cuttings or seed. 
Infected cuttings do not, of course, enter into the problem as far as maize 
is concerned, but in the case of sugar cane and of the wild grass, Saccharum 
spontaneum , the Sclerosporas are spread to a limited extent by this means. 
At Bontoc in the Mountain Province the writer found in January, 1920, that 
almost all the numerous small patches of cane grown in and around the 
Igorote villages were heavily infected with an oogonial Sclerospora; and 
there was strong evidence that the indiscriminate use of infected cuttings 
had, at least in part, been responsible for its spread. This cane, however, 
probably because it is a thin, hard-stemmed, purple variety with a rather 
low yield, had not been distributed widely; and as far as the writer was 
able to determine the disease is restricted to the one locality. Introduc¬ 
tion of this cane into the sugar-producing regions of Calamba, Pampanga, 
or Negros would be extremely dangerous. Except at Bontoc no instances 
of distribution of Sclerospora by mycelium in sugar cane were noted in the 
Philippines. The only other case of Sclerosporal infection of sugar cane 
seen by the writer was a single plant attacked by the conidial form, 
Sclerospora spontanea (25), and so weakened and stunted as to be useless 
for cuttings. It should be noted, however, that distribution of the Sclero¬ 
sporas by this means is greatly to be feared, especially by remote countries. 
It was through the importation of cuttings infected by the mycelium of 
Sclerospora sacchari that this destructive disease was introduced into 
Formosa from Australia (15) . 4 
In the case of the wild grass, Saccharum spontaneum , also, spread of 
Sclerospora is accomplished to some extent by infected cuttings. In 
certain provinces, especially Laguna and Pangasinan, it is a common 
practice to plant this grass by means of cuttings, as a binder along the 
newly made retaining walls between rice paddies. In those provinces 
the oogonial Sclerospora which has previously been mentioned (25) is 
very prevalent on the grass, and as the farmers, ignorant of the true 
nature of the disease, make no effort to select healthy stems, the mildew 
is frequently transplanted in the cuttings. As a result, in the newly 
grown grass borders of these fields the writer commonly encountered 
extensive infections which in location, age, and other characters gave 
clear evidence of arising from infected cuttings. Experimental plant¬ 
ings, using diseased stalks, developed similar extensive infections. In 
the case of plants of this grass parasitized by the conidial Sclerospora 
spontanea the writer also found experimentally that cuttings could carry 
the disease, but no instances of such transmission of the conidial stage 
were observed in the field. 
4 Since this was written the writer has learned from Mr. H. A. Tee, of the Philippine Bureau of Science, 
that Sclerospora sacchari has recently been introduced into the Philippines from Formosa in cuttings whose 
infection remained undetected through inspection in Formosa and Manila and persisted uninjured through 
precautionary dipping in Bordeaux mixture. 
22330—23-4 
