556 EXPERIMENT STATION RECORD. [Vol.37 



two different specimens of avocado trees, was introduced into trunks of avocado 

 trees in two different seasons, and produced effects similar to those on the trees 

 from which it was isolated. 



Banana disease on the Salayer Islands, A. B. Rijks (Dept. Landb., Nijv. 

 en Handel [Dutch East Indies'\, Meded. Lab. Plantenziekten, No. 21 {1916), pp. 

 16, pis. 4). — Observations made since November, 1915, are reported on the 

 disease which is the cause of increasing loss to banana culture in several islands 

 of the Salayer group. The author gives an account of some conditions appar- 

 ently related to the prevalence of the disease, such as location, climate, soil, cul- 

 ture, light intensity, and varieties differing in resistance to the disease. The 

 trouble appears in the young roots, later attacking the older ones and almost 

 completely suppressing the root system of the plant. 



Characteristics of citrus canker and of the causal organism, R. A. Jehle 

 (Quart. Bui. Plant Bd. Fla., 1 (1911), No. 2, pp. 24-^7, figs. 20).— This paper 

 aims to give such information, additional to that previously noted (E. S. R., 36, 

 p. 352), as may enable citrus growers to obtain an adequate knowledge of 

 citrus canker. 



Apparently the disease is distributed by such mechanical carriers as rain, 

 dew, insects, and in particular, men and domestic animals. Experiments on 

 young plants kept in screened cages, which are described, indicated the causal 

 agency of Bacterium (Pseudomonn^) citri. Probably ripe fruits are not at- 

 tacked, but they may serve as mechanical carriers. 



The symptoms are described as being very similar on all the parts attacked. 

 On twigs the cankers do not penetrate the wood. The period within which 

 infection becomes obvious, after inoculation, may vary greatly, being influenced 

 by weather or seasonal conditions and the vigor of the host, as are also the 

 prevalence and severity of the canker. 



Cooperative work for eradicating citrus canker, K. F. Kellkbman (17. S. 

 Dept. Agr. Yearbook 1916, pp. 267-272, pis. 4). — A popular description is given 

 of the citrus canker due to Pseudomonas citri, together with an account of the 

 cooperative work for the eradication of this disease carried on by the Depart- 

 ment of Agriculture and various Gulf States as outlined. 



Department of citrus canker eradication, F. SxraLiNQ (Quart. Bui. Plant 

 Bd. Fla., 1 (1917), No. 2, pp. 50, 5i).— Giving data for 1914 to 1916 which he has 

 compiled on the canker eradication work conducted In cooperation with the 

 U. S. Department of Agriculture, the author states that citrus canker has been 

 found on 441 properties in 22 Florida counties, there were still being classed 

 as infected in 1916. 150 properties, 12 properties in 3 counties showing active 

 infection at that time, of which 4 cases were regarded as new. The number 

 of infected trees showed high maxima in August, of 1914, May and August, of 

 1915, and a much lower maximum in June, 1916, the range during that year 

 being much lower than that for the other two years. 



Citrus scab, H. S. Fawcett (Phytopathology, 6 (1916), No. 6, pp. 442-U5).— 

 The author reviews and criticizes the conclusions of Grossenbacher regarding 

 the cause of citrus scab (E. S. R., 36. p. 352). He also reviews some of his 

 own investigations carried on at the Florida Experiment Station (E. S. R., 27, 

 p. 653), which are considered to indicate definitely that Cladosporium citri is 

 the cause of citrus scab. 



Report of the mycologist, W. Nowelx (Imp. Dept. Apr. West Indies, Rpt. 

 Agr. Dept. Montserrat, 1915-16, pp. 9-12). — Limes in the district near Plymouth 

 exhibited a progressive dieback of the branches, and another, supposedly dis- 

 tinct therefrom, of the I'oots. The symptoms, which are discussotl for each 

 case, suggest that both troubles result from conditions unfavorable to vigorous 

 growth in this locality. The conditions considered as significant are the 



