348 EXPERIMENT STATION RECORD. 



relating to the parasitology of the red rot fungus of sugar cane (CoUetotrichum 

 falcatum). 



As a result of their investigations it is found that the fungus in the West 

 Indies is a facultative wound parasite, the degree of parasitism varying accord- 

 ing to climatic conditions, age, and particularly with the variety of cane. The 

 ohief injury done is in consequence of its invert action on cane sugar, tending 

 to increase the glucose ratio. The chief mode of infection seems to be through 

 the agency of boring insects, or through wounds caused by other means. 



The experiments are held to show that the disease is not communicated by 

 infected cuttings. The pre'^ence of the fungus in cuttings of mature canes 

 seems to stimulate shoot development and the growth of roots at the base of 

 the shoots, apparently in order that the new plant may cut itself off from the 

 source of infection. The chief danger from planting infected cuttings seems 

 to lie in the fact that the soil becomes infected with the fungus, thereby 

 Increasing the chance of the disease being communicated by boring insects. 

 While it is thought that tliis disease may be perpetuated through diseased 

 cuttings in other regions, it is not considered probable that it is transmitted in 

 this way in the West Indies. 



The fire blight disease in nursery stock, V. B. Stewaet (New York Cornell 

 iita. Bui. 329, pp. 315-371, figs. 15). — A description is given of the fire blight 

 of pomaceous trees, due to Bacillus amylivorus, with particular attention to 

 its effect on nursery stocli. The disease is most destructive on the cultivated 

 varieties of the pear, apple, and quince, and special attention is given to these 

 plants. 



I'ire blight in nursery districts is becoming very prevalent, and in some cases 

 entire blocks of apples, pears, and quinces were destroyed in 1908. In the 

 rursery the disease is said to be most commonly found affecting the twigs, the 

 one exception being the two-year-old and three-year-old quince stocks, which 

 often flower profusely. 



Detailed descriptions are given of the etiology of the disease, the results of 

 cultural studies on the organism, its life history, etc. 



The disease is largely distributed by insects and pruning tools, and seems 

 favored by certain weather conditions as well as cultivation and manuring of 

 the plants, which produce rapid, succulent gi'owth. As a result of 4 years' 

 work in the nursery the author believes it is profitable to give careful attention 

 to the fire blight. Eradicating the hold-over blight, removing quince blossom 

 buds, and the frequent inspection of diseased areas will reduce the disease. 



A bibliography of the subject is appended. 



The control of canker in the orchard, J. R. Coopee {Nel>r. Hort., 3 (1913), 

 No. 3. pp. 1, 2). — Suggestions are given for the control of cankers in orchard 

 trees, particularly the blister canker, bitter rot canker, and black rot canker. 

 The methods described involve proper sanitation in the orchard and removal 

 and destruction of infected parts, followed by proper sterilization or other 

 treatment of cut surfaces. 



Injury to orchard trees by crown gall, E. A. Back (Rpt. State Ent. and 

 Plant Path. Va., 8 (1910-11), pp. 31-S9, pis. 19). — Attention is called to an 

 experiment begun in 1906. which was planned to ascertain certain facts regard- 

 ing the crown gall of fruit trees. 



Careful notes were taken in the spring of 1906 on ISO trees diseased with 

 crown gall which exhibited every gradation of the disease. Some of the trees 

 died outright, while notes were taken on the others. On October 23. 1909, of 114 

 trees that were still living, 85 were found so badly affected by crown gall that 

 they had made no good root system. The remaining lot were not badly affected, 



