158 EXPERIMENT STATION RECORD. 



ment on certain organisms. The drop fungus of lettuce {Schrotinia sp. ) is greatly 

 accelerated in its activity by such treatment. The resting spores of many other 

 fungi are doubtless affected in the same way. With lettuce it has been repeatedly 

 observed that such drying of soil results in a stunted growth, producing an abnor- 

 mally colored and worthless crop. The texture of the plants is poor, the leaves being 

 thick and tough and inclined to crinkle. As showing that this condition is brought 

 about by desiccation alone, it is stated that wherever any drip from the roof fell 

 upon the soil plants grown in such places were always normal, and distinctly sharp 

 lines can be observed in the lettuce crop grown under such conditions. It is sug- 

 gested that the soil in lettuce houses should not be allowed to become too dry 

 during summer, but if this occurs the soil can be renovated by applying hot water 

 or steam to it, as has been previously shown. 



During the past season the growing of muskmelons was attended with consid- 

 erable loss due to the melon blight caused by Alternaria and the anthracnose {Colle- 

 totrichum lagenarium) as well as the attacks of the downy mildew {Plasmopara 

 cuhensis). The Alternaria during the season was less abundant than previously, but 

 the anthracnose was quite common. The downy mildew has been comparatively 

 unknown up to the present time when it occurred upon muskmelons over widely 

 extended areas. With the exception of the anthracnose, the chief troubles with 

 melons occur about September 1 as the fruit begins to mature. As considerable 

 success has been attained by spraying for the prevention of these diseases, the 

 authors suggest thorough spraying throughout the season, beginning as early as 

 July 1. 



The stem rots of chrysanthemums, carnations, and asters are described at some 

 length, the latter disease having already been noted (E. S. R., 13, j). 1060). 



The asparagus rust continues to be a serious factor among the large growers of this 

 vegetable. A large number of inquiries have been instituted in which the effects of 

 dew, elevation, and shelter on infection were investigated. In no instance was the 

 shelter produced by forest growth found to exert any beneficial influence; but there 

 seemed to be considerable differences in the amount of the disease apparently attribu- 

 table to the slope of the ground. It is possible that dew plays a part in asparagus 

 rust infection in those regions where the conditions are favorable for an outbreak 

 from the uredospore form of the fungus. Experiments in spraying were conducted, 

 following the recommendations of the New York State Station (E. S. R., 13, p. 147). 

 This method proved an expensive one and asparagus growers do not favor it. Fully 

 as beneficial results were obtained by an application of Paris green. This method is 

 a cheap one and is considered worthy of further trial. 



The sterilization of soil in greenhouses for the prevention of fungus diseases has 

 been under consideration at the station for a number of years. It has been recom- 

 mended for the extermination of soil fungi such as Rhizoctonia, Pyfhium debaryanum, 

 nematode worms, Botrytis sp. , etc. During the past year the commercial use of this 

 method has been greatly extended. The effect of sterilized soil on the growth of 

 plants has been noted, and for the purpose of determining this factor 2 beds of equal 

 size were selected, one of which was treated with hot water until the soil was soaked 

 and showed an average temperature of 145° F. at a depth of 4 in. The seed was 

 planted in boxes of earth which had been heated to 212° F. with steam. The other 

 bed remained untreated, the only difference in the 2 lots being the hot- water treat- 

 ment. These beds were planted to lettuce and the weight of the largest as well as 

 the weight of typical plants showed a gain of 33 per cent in favor of the plants 

 grown upon the treated soil. Various methods of sterilizing on a commercial scale 

 are described at considerable length. 



Notes on fungus diseases, H. H. Lamson {New Hampshire Sta. Bui. 87, pp. 

 127-130). — Brief descriptive notes are given, together with suggestions for the pre- 



