CALIFORNIA CITRUS CULTURE. 47 
organisms for their support. If the supporting organism is dead, we 
call them saprophytes, in which case they do no harm. If living, then 
they are parasites, and may work us great harm. They often produce 
myriads of spores, very small seed-like bodies by which they reproduce. 
Many put forth minute, thread-like growths, called hyphe, or the tangle, 
mycelium. These threads which form the common mold, push into the 
living tissue and sap from it its substance, or, to state it otherwise, feed 
upon it. The larger and more highly developed are familiar to us in 
the toadstools and mushrooms, others in the rusts, molds and mildews. 
Blue Mold (Penicillium italicum) and Green Mold (P. digitatum). 
We are all familiar with these molds. The myriad spores give the 
color, blue or green. They are the common cause of rot in all citrus 
fruits, and are not uncommon in many other fruits. They attack 
almost exclusively injured fruit. This formerly was the cause of 
millions of dollars loss to citrus growers. The masterly researches of 
Mr. G. Harold Powell, expert of the United States Department of Agri- 
culture, demonstrated the cause and remedy for this common rot, so 
that now the loss from this cause is much lessened. Clpping and 
handling the fruit so carefully as to produce no injury is a great pre- 
ventive, and precooling or cooling it off in the cars by icing so that no 
spores can germinate, has decreased the decay very greatly. The motto 
of every citrus grower should be, ‘‘Handle all fruit as though it were 
eggs,’’ and never bruise or wound in the least degree. Yet it remains 
to be said that some fruit, fruit from certain localities and fruit from 
orchards heavily manured, fails to stand up. There doubtless is sus- 
ceptible fruit. It may he physiologically weak. The attack is also 
increased apparently by a continued moist atmosphere. 
Brown Rot (Pythiacystis citrophthora). 
This is a very serious enemy of citrus fruits. The brownish color is 
very characteristic. It is observed on the fruit, the leaves and lower 
branches of the tree, in the packing-house and in the packed boxes. It 
spreads rapidly from fruit to fruit, wherever they touch in boxes or 
elsewhere. There is a characteristic odor of decomposing oil. It is 
most common on lemons. The fungus grows and fruits in the soil and 
in washing the fruit in the packing-house the spores that have blown 
on the lemons in the grove collect in myriads in the water and play 
havoe with the fruit, by being carried to every lemon. Professor Ralph 
E. Smith and H. J. Ramsey, of the University of California (Whittier 
Experiment Station), in suggesting bluestone (copper sulphate) as a 
eure, and in working out methods of sanitary treatment in the packing- 
house, conferred a rare service to the industry and to the State. Blue- 
stone is placed in the washing water in the packing-house. Straw 
