544 EXPERIMENT STATION RECORD. [Vol.40 



region showed the disease in 27 cities and villages of Luzerne, Schuylkill, and 

 Carbon Counties, Pa. With the exception of three points of infection, all the 

 localities lie within a rather restricted area. The disease is supposed to have 

 been brought from Europe in cargoes of potatoes received before 1912. The 

 nature and seriousness of the disease are described and the proposed meas- 

 ures for its control are indicated. 



Further data on the susceptibility of rutaceous plants to citrus canker, 

 H. A. Lee (Jour. Agr. Research [U. £.], 15 {1918), No. 12, pp. 661-666. pis. 4).— 

 An account is given from the Bureau of Plant Industry, U. S. Department of 

 Agriculture, of inoculation tests with Pseudomonas eitri on 24 species repre- 

 senting 20 genera of the family Rutaceae, which show that 19 of the species are 

 susceptible to a greater or less degree. From this it appears that citrus canker 

 is not limited to the genus Citrus, but has a wide range of hosts among the 

 Rutaceae. The investigations upon which this report is based were carried on 

 mainly at the Lamao Experiment Statjon of the Philippine Bureau of Agricul- 

 ture. 



Pecan rosette in relation to soil deficiencies, S. M. McMtTBRAN (U. S. Dipt. 

 Agr. Bui. 156 (1919), pp. 11, figs. 4).— Previous investigations (B. S. R., 32. p. 

 241) have shown that the pecan rosette is not associated with any definite para- 

 site but is rather the result of physical, chemical, or biological causes. With 

 this in mind, the author made a survey of a large number of pecan orchards on 

 various types of soil and under varying conditions of cultivation and fertiliza- 

 tion. 



While somewhat contradictory results were noted, at least 90 per cent of the 

 disease was observed under conditions which indicated a deficiency of humus, 

 plant food material, and moisture. Some experiments were undertaken with 

 mineral fertilizers, but where these weir applied to young orchards located on 

 pool- soils the resetted trees generally became worse under tin' treatment. In 

 the fitll of 1915, experiments were begun on three tracts of about 13 acr< 

 pecans located in southern Georgia, one plat in each trad received stable 

 manure alone at the rate of 20 tons per acre, a second plat -table maim: 

 the same rate with 1 ton of cottonseed meal, and a third plat cottonseed meal 

 alone at the rate of 1 ton per acre. 



The results of the applications are given in tabular form for the seasons of 

 1915 and 1917, from which It appears that the application of organic fertilizers 

 has greatly Improved the condition of the trees so far as the rosette is con- 

 cerned. "; line applied to a lot of trees was without effect in reducing rosette. 

 Experimental and other evidence is considered to indicate that pecan rosette 

 is a result of a deficiency of humus fertility, ami moisture supply. 



Brown canker of roses caused by Diaporthe umbrina. A. E. JENKINS (Jour. 

 Agr. Research [l\ S.I, 15 (191S), So. 11. pp. 593-600, pis. S, figs. 3).— The 

 author, of the Bureau of Plant Industry, I', s. Department of Agriculture, gives 

 a description of a canker of roses due to /'. umbrina n. sp.. which is said to be 

 widely distributed, being known to occur in the District of Columbia. Virginia, 

 West Virginia, Georgia, and Connecticut. 



The causal organism produces cankers on the rose stems, the diseased areas 

 being raw umber in color, sometimes surrounded by a purple border. Both the 

 pycnidlal and perithecial stages of the fungus have been produced in cultures. 

 and the disease has been produced on roses with both the pycnosporic and 

 ascosporlc stages. 



For the control of the disease, the author suggests the use of only healthy 

 stock for planting, the removal and burning of diseased canes from affe< ted 

 gardens, and the application of a fungicide in the fall, again in the spriug 



