1056 EXPERIMENT STATION RECORD. 



about the roots. When the usual supply of oxygen was withheld from the roots, 

 yellowish, reddish, or brownish spots appeared on the leaves and other aerial 

 portions of the stem within a few days. It was also observed that Piricularia 

 oryzce developed and fructified in some of these spots. 



In control plants, however, kept under proper conditions for growth, it was 

 found impossible to produce an infection with this fungus in a single case. 

 These experiments are held to confirm results previously obtained and indicate 

 that brusone is due to a deficiency or absence of free oxygen \i\ the vicinity of 

 the delicate absorbing rootlets. According to the author, practical rice growers 

 have found that there is more danger of brusone when the rice is dry in the 

 morning than when it is moistened with dew. These facts would be difficult to 

 explain if the disease were due to a fungus. 



While the author does not claim to have demonstrated beyond question the 

 cause of brusone, he believes that it is pi-obably due to the irregular or incom- 

 plete respiration of the minute absorbing rootlets still without a cork layer. 



The winter rot of potatoes (Jour. Bd. A<ir. [London], 13 {1901), 'Mo. 12, 

 pp. 739, I'/O, fig. 1). — A description is given of a rot of potatoes in cellars and 

 storage pits which is due to the fungus Mcetria solani. For the prevention of 

 this rot the writer suggests that potatoes "should be well dried before storing 

 and sprinkled with powdered sulphur during the process of drying. Land that 

 has produced a diseased crop will certainly be infected with the fungus and 

 should not be planted to potatoes again for several years. The use of lime or 

 kainit is recommended on infected land. 



Potato spraying experiment, E. P. Sandsten and .J. G. Milward (IF/s- 

 consin St a. Rpt. 1906, pp. 209-218, figs. 3). — In order to determine the actual 

 cost under ordinary farm conditions spraying experiments have been carried on 

 for the past 3 years in the principal potato-growing counties of the State. A 

 detailed account of these experiments is given in a previous publication of the 

 station (E. S. R., 18, p. 5.3). In 1905 experiments were conducted on 3 areas 

 of 30 acres each in which 5 applications of Bordeaux mixture were sprayed at 

 a cost of $3.70 per acre, the net gain ranging from $15.50 to $.36 per acre. 

 In 1906 another series of experiments was carried on in which the average gains 

 on 4 fields are expressed in yield per acre, the increases with 6 applications 

 being 18.9, 40, 47, and 29 bu. per acre, respectively. 



Pineapple and banana diseases, W. V. Tower (Porto Rico Sta. Rpt. 1906, 

 p. 27). — The author reports a serious trouble of pineapples following the plant- 

 ing of the crowns of the fruit. The plants rotted soon after l)eing set, the first 

 indication of disease appearing in the rotting of the lower leaves and under- 

 ground parts, and later extending to the center leaves. The exact nature of the 

 trouble has not been determined, but it was found that drying the crowns for 8 

 or 10 days before planting materially reduced the losses. 



The disease of bananas briefly described is believed to be of bacterial origin 

 and is characterized by the darkened areas found throughout the pseudotrunks 

 of the plants. The affected portions of the plants have a very disagreeable 

 odor. From the author's observations it is believed that much damage may 

 result from this disease. A similar disease is said to have been reported in the 

 Leeward Islands. 



A disease of coffee, J. W. Van Leenhoff (Porto Rico Sta. Ri>t. 1906. p. 32). — 

 The author briefly describes a fungus disease which attacks coffee berries, the 

 fungus apparently passing through the parchment and causing warty excres- 

 cences to appear on the grain. The disease was found to occur on trees grown 

 in shade as well as on those without shade, but perfectly healthy trees were not 

 observed to be affected. An examination of fresh berries indicated that the 

 cause was probably Stilhum flavidum. Trees sprayed 3 times with Bordeaux 



