376 EXPERIMENT STATION RECORD. 



hyphse pass through cells they become inclosed in a cellulose tube which may subse- 

 quently become more or less thickened. The changes produced in the nuclei of 

 hosts, the development of haustoria, etc., are described, and on the whole the work 

 treats of the subject from a somewhat new point of view. 



Ripe rot, or anthracnose, of banana {Agr. News [Barbados], 4 {1905), No. 83, 

 p. 189). — A brief note is given on a ripe rot or anthracnose of bananas, an account of 

 which has been previously presented (E. S. R., 15, p. 486). 



Thrips and black blight, H. A. Ballou (Bot. Dept. [Trinidad], Bui. Misc. Inform., 

 1904, No. 44, pp. 132-135). — A report is given of investigations carried on by the 

 author on the thrips of cacao and the black blight. 



The thrips (Physopus rubrocinctus) has been known in Grenada for a number of 

 years, and where present in abundance is associated with the black blight. This 

 blight is due to the fungus Capnodium, which finds its most favorable conditions for 

 growth in the secretions of scale insects. A list of trees is given upon which the 

 black blight was conspicuous, among them being the mango, breadfruit, sapodilla, 

 guava, limes, and oranges. 



No serious attack of black blight has been observed on cacao or nutmeg, and it is 

 believed that until scale insects attack these plants the black blight will not. The 

 control of the fungus is a rather simple affair, and consists of spraying to destroy the 

 various scale insects. 



Pod diseases of cacao [Agr. News [Barbados], 4 {1905), No. 83, p. 189). — There 

 are said to be 3 pod diseases of cacao, only 2 of which are of serious importance in 

 the West Indies. These are the Trinidad pod disease, caused by the fungus Phytoph- 

 thora omnivora and the brown rot due to Diplodia cacaoicola. Both of these diseases 

 are described, and precautionary measures of burning or burying the pods are 

 recommended. 



Witch broom disease of cacao {Agr. News [Barbados'], 4 { 1905), No. 78, p. 105 |. — 

 This disease, which has been considered a very destructive one, the author claims is 

 a consequence of poor development of trees, the roots frequently being set in ground 

 that is perfectly saturated with water for several months at a time. The result of 

 planting in such a situation is a weak growth, making the trees particularly suscep- 

 tible to fungus attack. It is also observed that trees that are more than 35 years old 

 are also subject to the fungus by reason of their impaired vitality. 



Disease in immortelles {Bot. Dept. [Trinidad], Bui. Misc. Inform., 1904, No. 44, 

 p. 148). — For some time complaint has been made that cacao shade trees were dying 

 in certain regions, the tree most affected being the immortelle, Erythrina umbrosa. 



Diseased specimens which were examined showed the presence of abundant fungi, 

 but as yet the character of the fungus has not been determined. The investigations 

 seemed to show that this species of tree is poorly suited to the soil and situation 

 where the disease has appeared, and probably some other shade tree should be sub- 

 stituted for it. 



A disease of black oaks caused by Polyporus obtusus, P. Spaulding {Mo. 

 Bot. Gard. Ann. Rpt., 16 {1905), pp. 109-116, pis. 7, map 1). — A disease caused by 

 the fungus Polyporus obtusus, which was quite destructive locally to several species 

 of oak trees, is described. 



The fungus seems to be confined to North America and its distribution is indicated. 

 So far as known it occurs only on species of oak belonging to the black oak series, 

 and seems to be associated with the attacks of an oak-boring insect which is believed 

 to be Priono.i)/st us robinise. The spores of the fungus are apparently blown into the 

 entrances of the burrows, where they germinate and the fungus grows following the 

 burrow until the heart of the tree is reached. Here the heartwood becomes affected, 

 and the rot extends through the wood of the trunk until the top is broken by the 

 wind or the weight of the tree. 



