170 



The Philippine Journal of Science 



Vigtia spp. — Continued. 

 Fitsarium. 



Phoma bakeriana Sacc. 

 Rhizoctonia. 

 Lredo vignae Bres. 

 Xanthosoma sagittifolium Schott. 



Yautia. 

 Vermicularia xanthosomatis 



Sacc. 

 Zea mays Linn. Corn, maize. 

 Acerbia viaydis Rehm. 

 Broomella zeae Rehm. 

 ClasterosjJoHwm maydicum Sacc. 

 Dry rot, sterile fungus. \ 



Fusarium. I 



Helminthosporium curvulum 



Sacc. 

 HelminthospoHinn inconspicuum 



C. et E. 

 Leptosphaeria orthogramma (B. i 



et Br.) Sacc. I 



Physalospora lineai-is Sacc. I 



Sclerospora viaydis (Rac.) Butl. 

 Ustilago zeae (Beckm.) Ung. I 



Control of plant diseases. 

 General discussion. 

 Plant sanitation. 

 Crop rotation. 

 Cultural methods. 

 Disease-resistant varieties. 

 Soil sterilization. 



Direct-heating method. 



Formalin disinfection. 

 Fungicides. 



Standard Bordeaux mixture. 



Burgundy mixture. 



Soda Bordeaux mixture. 



Ammoniacal solution of copper 

 carbonate. 



Resin-salsoda sticker. 



Sulphur. 



Lime-sulphur spray. 



Self-boiled lime-sulphur spray. 



Formalin spray. 



Formalin. 



Corrosive sublimate. 



Spraying apparatus. 



INTRODUCTION 



Fungous diseases are found on practically all cultivated and 

 wild plants in Laguna Province, Philippine Islands. From this 

 local abundance it is to be presumed with a great degree of as- 

 surance that they are equally prevalent in most, if not all, the 

 other agricultural regions of the Islands. They are often the 

 limiting factors in the raising of many agricultural crops. 

 Climatic conditions of the Philippines account for the great 

 number and destructiveness of plant diseases, for the growth 

 and development of fungi are enhanced by warmth and moisture. 

 During the rainy season both of these factors are present, there- 

 by aiding the large destruction during this period of the year. 

 Plant diseases are seasonal ; that is, they are more numerous and 

 severe during the wetter months of the year, extending from 

 July to November. A person going through the Islands during 

 the dry season will not be impressed with the number and des- 

 tructiveness of plant diseases, but during the rainy season the 

 reverse will be found true. No complete estimates of losses due 

 to plant diseases have been prepared in the Philippines, but it 

 would be safe to say that in this section of the country at least 

 10 per cent of agricultural crops are destroyed by fungi. 



Certain articles on phytopathology in the tropics give an en- 



