XIII, A, 4 Reinking: Philippine Economic-Plant Diseases 189 



FRUIT rot: penicillium 



Symptoms. — Fruit rots are present on fruit kept for some 

 time out of storage. The Penicillium rot is characterized by 

 the production of a green powdery mass of spores over the soft, 

 rotted area. The rot starts at some injury and gradually spreads 

 until the entire fruit is involved. 



Causal organism. — The fungus penetrates the tissue of the 

 fruit, causing a soft rot. It produces an abundance of typical 

 Penicillium spores on the surface of the fruit. These spores 

 blow from diseased to healthy fruit, thereby causing infection. 



Control. — The fruit should be kept free from injuries. It 

 should be used as soon as possible, and if stored it should be 

 kept in a well-aerated place so as to avoid excessive moisture. 



Phyllosticta circumsepta Sacc. has been found on the dying 

 rind of fruit. 



GUMMOSIS 



Symptoms. — A gumming of the trunk, stem, and fruit occurs. 

 Whether this is due to unfavorable climatic conditions, to lack 

 of cultivation and care, or to parasites has not been fully deter- 

 mined. The disease of the stems is more severe in poorly kept 

 orchards. Insect • punctures in the fruit have been observed to 

 result in a gumming; mechanical or fungus injuries, as in the 

 case of citrus canker, may also cause a gumming. It appears 

 that gummosis of stem and fruit here is not caused by any 

 one definite organism or factor. 



LICHENS 



Symptoms. — Lichens are found in abundance, growing over 

 all woody parts and even upon the leaves of trees, producing 

 greenish gray blotches. The damage done appears to be slight; 

 however, the normal physiological activities of the plant must 

 be disturbed thereby. 



Control. — Lichens can be reduced by the use of a spray or wash 

 of 6 per cent copper sulphate solution or by judicious spraying, 

 as discussed under citrus canker. 



MOTTLED LEAF: NONPARASITIC 



Symptoms. — Leaves thus diseased are characterized by a dis- 

 tinct yellowing of the leaf mesophyll between the large lateral 

 veins. The tissue adjacent the midvein and the larger lateral 

 veins is of a healthy green. Entire trees may be affected, but 

 often only leaves on special branches are diseased. When the 

 entire tree is affected, it is much dwarfed and may later die, 

 due to secondary agencies. Badly diseased trees commonly show 



