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 hyphae, 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 arid 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. Clipping 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 be 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 

 havoc 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 

 cure, 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 



