254 EXPERIMENT STATION RECORD. 



apples the results were mure evident, as the yield of first-class fruit on the sprayed 

 trees was considerably in excess of that upon the unsprayed ones. 



Notes are given on the l^acterial pear blight caused by Bacillus amylovorus, and the 

 organism described. A number of inoculation experiments were conducted from 

 which it was found that only the more tender and succulent parts of trees become 

 infested and that second-year wood is not lial)le to become diseased even when 

 injured or punctured. No infection results from the mere contact of the organisms 

 with the surface of plants, and mechanical contact of blighted with healthy portions 

 of trees is not liable to result in infection. As a means for preventing the spread of 

 this disease the author recommends pruning of the blighted terminal shoots, and 

 several weeks after l)looming is suggested as the best time for performing this opera- 

 tion, since at that time all the infection of the year is liable to show itself. 



The canker in apple and pear trees, due to Sphxrojms malorum, is described at 

 some length. This disease has been quite injurious in some parts of the State. It is 

 frequently mistaken for fire blight, but can be readily distinguished by the shrink- 

 ing and cracking of the bark over the infected areas. All diseased wood should be 

 cut out and burned and the main trunk and body of the trees be protected with a 

 wash of whale-oil soap, slaked lime, water, and wood ashes, or ordinary Bordeaux 

 mixture with enough lime added to bring it to the consistency of whitewash. 



Pear blight and pear canker, F. D. Chester {Dekurare Sta. Bui. 52, pp. S, figs. 

 7 ). — This is essentially a reprint from the Annual Report of the Station for 1900. (See 

 above. ) 



Investig-ations on a parasite of flax, E. Laurent {Bid. Agr. IBrussels'], 16 

 {1900) , No. 6, pp. 511-554, pi. 1). — A report is given of a study made to ascertain the 

 cause of a blight of flax. The author claims that it is due to the fungus Asterocgstis 

 radicis. This fungus plays an essential role in the development of the disease, 

 although it is frequently followed by a number of other fungi. In addition to flax, 

 it has been found that this fungus is parasitic upon the roots of a number of other 

 plants, especially when the plants are young. Among the known host plants are 

 mentioned spinach, radish, beets, peas, beans, alfalfa, white clover, cress, mustard, 

 spurry, and flax. The fungus, it is found, can enter the roots only at a certain stage 

 in their development, and the author conducted an extensive series of experiments 

 to determine this period. In the case of flax, it is not possible to gain entrance after 

 the thirteenth or fourteenth day from germination. It develops in the parenchyma 

 and root hairs of the young root. It is propagated immediately by zoospores, which 

 are very sensible to drying and to fungicides. For the preservation of the fungus, 

 there are developed within the roots winter spores which are liberated by the decay of 

 the roots. As a means for preventing the disease, rotation of crops is recommended, 

 but it is stated that flax should not be grown on infested soil for at least 7 years after 

 the fungus is known to be present in the soil. 



Treatment of oats for smut, A. D. Shamel {Illinois Stu. Bui. 64, j^p- 57-72, 

 figs. 6). — The amount and nature of oat smut are described, and suggestions given for 

 prevention by means of the hot w-ater and formalin treatments. Experiments were 

 conducted in which the seed was heated in water at temperatures of 125, 132, 137, and 

 140° F., and the amount of smut, yield of grain and straw determined. Similar 

 areas were sown with seed taken from the same lot, but not given any treatment, 

 which showed from 2\ to 9»per cent smut in the crop, the yield of grain varying from 

 27^ to 46 bu. ; while in the different treatments the amount of smut varied from to 5 

 per cent, and the grain crop from 22| to 50 bu. The same varieties of oats were 

 submerged in a formalin solution, consisting of 1 pt. of formalin to 25 gal. of water. 

 The oats were placed in sacks and immersed for 10 minutes, after which they were 

 immediately sown. The resulting crop contained no snnit, and the yield of grain 

 was 31.2 to 69.3 bu. per acre. 



Formalin as a preventive of oat smut, W. Stuart {Indiana Sta. Bui. 87, pp. 



