182 The Philippine Journal of Science 1918 



CARICA PAPAYA LINN. PAPAYA 

 DAMPING off: RHIZOCTONIA AND PYTHIUM DEBARYANUM HESSE 



Symptoms. — Frequently young seedlings are attacked by soil 

 fungi just at the surface of the ground. The stem first becomes 

 watery, then turns brownish, and shrivels up, resulting in the 

 falling over of the plant. 



Causal organism. — Either of two common soil fungi, Rhizoc- 

 tonia and Pythium debaryanum Hesse, may produce the dis- 

 ease. The Rhizoctonia grows well in pure culture, producing a 

 brownish mycelium and brown sclerotial bodies. Pythium may 

 be recognized in the plant tissue by its characteristic fruiting 

 bodies. 



Control. — All soil used for the growth of seedlings should be 

 sterilized. Seed flats should be placed in a well-aerated place 

 and sunned from time to time. 



FRUIT rot: fusarium 



Symptoms. — Frequently a Fusarium, causes the rotting of 

 mature fruit. The rot is similar in appearance to that caused 

 by Phytophthora, except that the surface of this rot is covered 

 with the dense growth of Fusarium. Spores are produced in 

 abundance. Often rots are accompanied by various mold fungi, 

 among them being a Rhizopus and a Penicillium. 



FRUIT ROT: LASIODIPLODIA THEOBROMAE (PAT.) GRIFFON ET MAUBLANC 



Symptoms. — A somewhat dry rot of papaya fruit is due to 

 the attacks of this fungus. The diseased fruits are characterized 

 by the production of a sooty black mass of fungus spores on 

 the surface. 



Causal organism. — This fungus is the same as that producing 

 a dry rot of cacao pods, root crops, and other vegetables. 



Coyitrol. — All fruit rots may be controlled by taking care that 

 no injuries are produced on the fruit during harvesting and that 

 the fruit is used before becoming soft. 



FRUIT rot: PHYTOPHTHORA FABERI MAUBLANC 



Symptoms. — This fungus may cause a soft rot of the mature 

 fruit. The rot starts usually at some injury and spreads until 

 the entire fruit becomes involved. Diseased fruits are covered 

 by a white fungous growth. 



Causal organism. — The organism producing this disease is 

 the same as that producing the black rot of cacao pods. Conidia 

 and oospores are developed in abundance by the fungus. The 

 fungus grows well in pure culture, being easily obtained by 



