A NEW FUNGUS OF EGONOMIC IMPORTANCE. 
Ratpu E. SMitH AND ELIZABETH H. SMITH. 
(WITH THREE FIGURES) 
AMONG the subjects of investigation by the California Agricul- 
tural Experiment Station, that of a destructive rotting of lemons 
Occurring in southern California is one of the most important. 
The cause and means of control of this rot have been a complete 
mystery to the handlers of lemons, and the fact that the trouble has 
been found to be due to a fungus representing not only a new species, 
but a well-defined new genus, makes the case one of peculiar interest. 
The rot in question has been called the “brown rot,” distinguish- 
ing it from the “blue mould,” or Penicillium rot, the commonest 
form of Citrus decay. The latter has been known since time imme- 
morial, but with the best class of lemon shippers is not usually a great 
pest. Lemons affected by Penicillium are almost invariably those 
which have become bruised in handling or subjected to improper 
conditions. With fruit properly handled, cases of blue mould are 
only occasional, In these the affected lemon decays and becomes 
covered with the dusty fungus, finally collapsing into a slimy mass, 
without infecting the other fruit, even though they be covered with 
the spores, A Penicillium-affected lemon in the midst of a box 
does not usually infect the other fruit about it in the least when 
Proper conditions are maintained. 
Within the past few years a new and much more serious form 
of Tot has been detected by the lemon growers and shippers. In 
lemons which had been picked, washed, and stored for curing, it 
Was found that a rot ‘developed which spread rapidly by contact 
through the fruit, soon involving the entire box if left undisturbed. 
4 @ppearance the affected lemons are characteristic and easily 
distinguished from those affected by blue mould, though the latter 
Pei follows rapidly on the other and soon covers the decaying 
nase - Particularly characteristic is the odor of lemons affected by 
wn rot, a peculiar rancid smell by which an experienced person 
can detect one affected lemon in a large amount of fruit. This 
415] Botanical Gazette, vol. 42[ 
