196 PATHOLOGY [BoT. Absts., Vol. VIII, 



the number of infections, the length of incubation, and the severity of the disease. — Environ- 

 mental conditions play an exceedingly important role in the susceptibility and resistance of 

 citrus plants to canker and "the results indicate that it will be necessary to study the behavior 

 of the host plant to its environment and its relation to the causal organism before any scientific 

 selection or breeding for disease resistance can be made." — Pertinent literature is reviewed and 

 a bibliography of 17 titles is appended. — D. Reddick. 



1358. Rands, Fkederick V., and Lillian C. Cash. Some insect relations of Bacillus 

 tracheiphilus Erw. Sm. Phytopath. 10: 133-140. 1920. — A few striped cucumber beetles 

 were found carrying the wilt organism internally during the winter. Infection may occur 

 from the mouth parts of wilt-fed beetles for a time after feeding and also when the feces of the 

 same beetles come in contact with fresh leaf injuries involving the vascular system. The 

 organism has been isolated from the viscera of wilt-fed beetles. — S. P. Doolittle. 



1359. Rands, Frederick V., and W. Dwight Pierce. A coordination of our knowledge 

 of insect transmission in plant and animal diseases. Phytopath. 10: 189-231. 1920. — The 

 writers present a review of the literature dealing with insect transmission of plant and ani- 

 mal diseases, with particular reference to diseases of plants. A distinct correlation is found 

 in the principles which apply to insect transmission in both branches of pathology. Insects 

 may act in 3 general relations to diseases caused by micro-organisms: (1) External trans- 

 mission in which the infective principle is carried on the external body parts of the insect; 

 (2) insects without carrying infection themselves may cause wounds through which parasite 

 organisms gain entrance; (3) internal transmission in which the organism is taken up and 

 passed unharmed through the body of the insect. The transmission of various fungous, bac- 

 terial, and "virus" diseases is reviewed in these relations. — S. P. Doolittle. 



1360. Sauvageau, C. Sur le parasitisms d'une algue rouge. (Polysiphonia fastigiata 

 Grev.) [Concerning the parasitism of a red alga.] Compt. Rend. Acad. Sci. Paris 169: 1383- 

 1386. 1919. — Certain marine algae support a varied and abundant flora while others do not. 

 The plants attached to them may be classified as epiphytes or parasites. Most of the endo- 

 phytic algae are restricted to one host plant or to a relatively small number of host plants. 

 Polysiphonia fastigiata is found in dense tufts attached to Ascophijllum nodosum, and al- 

 though it has been described as being merely an epiphyte, the author finds that its structure 

 and development indicate that it is a true parasite. It is rarely found attached to Fucus 

 platycarpus and F. vesiculosus. — V. H. Young. 



1361. Smyth, E. Gratwood. Insects and mottling disease. Jour. Dept. Agric. Porto 

 Rico 3*: 83-116. 1919 [1920].— The insects which might be associated with the transmission 

 and spread of sugar cane mosaic are described. A "summary of our knowledge of insect- 

 borne diseases of plants occurring in America" is presented in tabular form and includes 18 

 diseases. Experimental methods are described and experiments with the different species 

 are presented in detail. Infection has been secured on 6 plants. The agents concerned are 

 West Indian cane fly (Stenocranus saccharivorus) , leaf scale {Pulvinaria iceryi), yellow cane 

 aphis {Sipha flava), and mealy bugs {Pseudococcus calceolariae and P. sacchari). A bib- 

 liography of insect-borne diseases of plants comprising 53 titles is appended. — D. Reddick. 



1362. Smyth, E. Graywood. An annotated bibliography of Porto Rican cane insects. 

 Jour. Dept. Agric. Porto Rico 3*: 117-134. 1919 [1920].— Brief abstracts of literature, pre- 

 pared in connection with work on insect transmission of sugar cane mosaic, are presented. 

 [See also preceding entry.] — D. Reddick. 



1363. Smyth, E. Graywood. List of the insects and mite pests of sugar cane in Porto 

 Rico. Jour, Dept. Agric. Porto Rico 3^: 135-150. 1919 [1920].— The paper, prepared in 

 connection with a study of insect transmission of sugar cane mosaic, gives for each organism 

 the name, distribution, food plants, injury done, enemies and method of control. [See also 

 the 2 preceding entries.] — D. Reddick. 



