850 EXPERIMENT STATION RECOBD. [Vol. M 



Pruning experiments t<yr control of melanose have been continned, and 

 where the trees were carefully pruned a higher percentage of first-class fruit 

 was obtained. 



In connection with the investigations of citrus canker, the author refers to a 

 previous publication (B. S. R., 32, p. 345) in which it is stated that the cause 

 of this trouble is a fungus belonging to the genus Phyllosticta. Subsequent to 

 that publication, inoculation experiments gave negative results, while suspen- 

 sions of a mixture of this fungus with bacteria isolated from cankered spots 

 produced the disease. This led to the belief that the disease is due to bacteria, 

 and this was soon after shown by Miss Hasse (E. S. R., 33, p. 149). The 

 constant association of the fungus with the canker is not readily explained, but 

 the author believes it may be a secondary agent in the enlargement of the 

 spots. The investigations now in progress include cultural reactions of the 

 organism, Pseudomonas citri, its relation to the host plant, and its ultimate 

 effect on the citrus tree. 



Brief notes are given on the stem end rot, citrus scab, and withertip of citrus 

 trees. 



A study of the pecan disease was begun on account of the serious injury 

 reported from various localities of the State. This disease was previously noted 

 (E. S. R., 23, p. 446) and the name dieback given it on account of the death of 

 the twigs and limbs of the trees attacked. The disease has been studied in the 

 field and the laboratory, and specimens usually show the presence of a number 

 of fungi. One of these has been identified as Botryosphccria berengerimm, which 

 seems to be quite constantly associated with the disease, and inoculation experi- 

 ments with the fungus have produced characteristic symptoms in most instances. 

 Experiments for the control of this disease are in progress, cutting out diseased 

 parts and applying Bordeaux mixture or lime sulphur solution being tested^ 



Some bark diseases of citrus trees in Florida, J. G. Gbossenbacheb {Phyto- 

 pathology, 6 (1916), No. 1, pp. 29-50, figs. 9). — A description is given of a num- 

 ber of diseases of citrus trees, together with suggestions for their treatment. 

 Among those described are gummosis, foot rot, crown rot, dieback, withertip, 

 and canker. 



The cause of coconut bud rot, J. R. Johnston {Estac. Expt. Agron. Cuba Bol. 

 27 (1916), pp. 3-101, pis. 15, figs. 6). — In a further report on the coconut bud 

 rot (E. S. R., 26, p. 649; 33, p. 150), associated with the presence of an organism 

 which appears to be practically identical with Bacillus coli, the present appar- 

 ent range of the disease is said to include many parts of both eastern and 

 western Cuba, western Jamaica with a few cases in the eastern portion, the 

 Cayman Islands, British Honduras, northern and eastern Trinidad, and British 

 Guiana. 



Direct inoculation gave positive results both with the organism taken from 

 diseased tissue and with that of animal origin. It is thought that rots of the 

 coconut palm previously ascribed by other writers to other causes may be shown 

 to be due to the same cause as the bud rot. 



The various fungicides are ineffectual as remedial agents, but precautionary 

 measures have given good results in most cases. 



Fungus diseases of coffee in Porto Rico, G. L. Fawcett (Porto Rico Sta. Bui. 

 17 (1916), Spanish ed., pp. 31, pis. 8). — This is a Spanish edition of the bulletin 

 previously issued (E. S. R., 32, p. 645). 



A withertip of fir, F. W. Neger (Naturw. Ztschr. Forst u. Landtc, 14 (1916), 

 No. S-4, pp. 121-127, figs. 4). — A withertip of fir is described. It appears to be 

 related to frost injury and to be associated frequently with Nectria cucurbitula 

 and more so with Dermatea eucrita. 



