158 EXPERIMENT STATION RECORD. 



due to unknown causes, such as melanose, die back, and blight, while the 

 bulletin closes with brief directions for the preparation and application of 

 Bordeaux mixtures. 



On the diseases of cacao, A. B. Baethe (Rei\ Agr. [^anto Domingo], 6 

 (1910), No. 5, pp. 103-112). — In a discussion of several common diseases of 

 cacao in tropical America, the author calls special attention to a brown rot of 

 the pods, or cacao canker, due, it is claimed, to a new species of Phytophthora 

 named by C. Maublanc P. faberi, a technical description of which is given. This 

 disease is said to destroy at times three-fourths of the cacao crop, and is favored 

 by dampness and shade. 



Spraying during the rainy season with a Bordeaux mixture, to which 250 

 gm. of colophony (a kind of resin) and 500 gm. of starch has been added, and 

 with a solution of copper sulphate in dry weather, is advised. In starting new 

 cacao plantations, greater distances between the plants, and the use of Hevea 

 bmsiliensis or Castilloa elastica as shade trees, are also recommended. 



A disease of tea seedling's, C. Bernard {BuI. Dept. Agr. Indcs Necrland., 

 1910, No. 40, pp. 39-48, pi. 1). — A description is given of a disease of tea seed- 

 lings in which the cortical layers of the radicle, as it pushes its way into the 

 ground, are destroyed. The pith is filled with the vegetative mycelium of a 

 fungus which seems to corrode and absorb the starch grains, thus preventing 

 the growth of the roots and finally killing the young seedlings. 



The primary cause of the disease seems to be a too prolonged soaking of the 

 seed before planting, and, perhaps, an excessive humidity in the nurseries at 

 the time of germination, thus permitting destructive fungi to develop. 



Another type of the disease is seen in the nurseries when the stems are at- 

 tacked just at the surface of the ground, causing the cortex to become depressed, 

 dry, and brown, while the interior cells present symptoms similar to those seen 

 in the pith of the diseased roots. The leaves of the young seedling wilt and 

 finally the entire plant dies. This type of the disease seems to be favored by 

 high temperatures and by an excessive humidity of the soil. 



No spores or conidia were found by which to identify the fungus, but its 

 mycelium resembles that of Rosellinia necatrix. As the disease is apparently 

 introduced into the soil with the seed, disinfection of the seed, followed by the 

 shading of the seedlings and good drainage of the nurseries, are recommended 

 as remedies. 



[Pests of Para rubber trees], H. N. Ridley and R. Derry (Agr. Bill. Straits 

 and Fed. Malay States, 9 {1910), No. 8, i)p. 289-297).— The authors state that 

 the fungus Fomcs scmitostiis seems to be spreading more slowly among the trees 

 at the place where it first appeared, while the destruction of stumps and roots 

 is proving the most successful preventive measure. 



A disease of the Para rubber tree (E. S. R., 22, p. 54S) is described, which 

 attacks the trees above the branches, causing the leaves to wither, while the 

 cambium is a pale, dull red and the bark has no latex in it. The trees die in 

 a few days when once attacked. From a dead stem killed by this disease, spores 

 of Diplodia rapax developed and were used for inoculation experiments on 

 healthy Para rubber plants. It was found that the growth of the fungus was 

 very rapid, as the spores germinated in 12 hours after inoculation, and the leaf 

 stalk thus diseased died in 6 days, while in about 4 days more fresh spores were 

 produced. No preliminary infection by Glceosporium was found necessary. The 

 fungus apparently can not attack healthy, uninjured buds, but can attack young, 

 imperfectly developed leaves. 



Further observations on Evtypa caulivora (E. S. R., 23, p. 750) indicate that it 

 is not a parasite, as was supposed, but only a saprophytic fungus. Injuries to 



