studies as have been made will occur in the forthcoming report of 

 the Experiment Station, (1916-1917). 



IXJUEIES DUE TO NATURAL AGENCIES. 



In order to round out the subject of cane disease, it has been 

 considered proper to include a consideration of injuries due to .such 

 pliysieal phenomena or natural causes, as lightning, wind, drouth, 

 and floods, often important sources of loss to the cane growers of the 

 Island. 



LIGHTNING. 



Lightning injury to sugar-cane is apparently rare, but one instance 

 having been observed (75). In this case all the cane, including the 

 I'oots, in an area of approximately a square rod was killed, producing 

 an open spot sharply set off from the surrounding normal cane. 

 Nothing was left of the cane but charred remains of leaves and 

 a few short pieces of stalk, some remaining erect. A growth of her- 

 baceous weeds followed. No insects or fungi weve present, even a 

 considerable time after the cane was killed. 



WIND. 



Under normal conditions cane is quite resistant to direct injury 

 from Avind, although of course there is the indirect effect of the in- 

 creased evaporation of the soil water supply, and checking of growth 

 or even death when a shortage occurs. 



The occasional hurricanes, however, often cause considerable losses 

 depending somewhat upon the season in which they occur, or upon 

 the age of the cane. With extreme wind velocities the cane may be 

 uprooted over large areas, making practically a total loss, or young 

 ratoons may be so wrenched and loosened as to give greatly decreased 

 yields. Over the eastern end of the Island a decided falling off in 

 estimated production was acredited to this cause in the season just 

 ended. 



Cane does not, however, suffer from wind to the extend that other 

 crops, coffee and citrus, for example, do. 



FLOODS, AND EXCESSIVE WATER STTPLY. 



Cane, a shall rooted crop is much subject to damage by floods. 

 During the periodic overflows, characterizing the rivers of Porto 

 Rico, much low land cane is washed out or the hold of the i)lants 

 so weakened Iw the washing away of the soil that an effort must ])e 

 put forth to recover, which must mean decreased yields. Cane is, 

 however, the most resistent crop to this soit of condition. 



233 



