964 EXPERIMENT STATION RECORD. 



ventilated cars or ventilated curing houses. The practice of wra])ping the fruits in 

 tissue paper also decreases the danger from rot. As a preventive means of distri- 

 bution the decayed fruit should be burned or deeply buried to destroy the spores. 

 Packing houses should be thoroughly disinfected and where possible sulphuring 

 should be resorted to. 



Notes on diseases of the orang-e, J. AV. Mills ( California Sta. Bid. 138, pp. 39-42, 

 figti. 2). — The important diseases of the orange in California are said to be gummosis, 

 a scaly bark gum disease, and die-back. The gumniosis attacks the roots and trunks 

 just below the surface of the ground and makes its appearance where the ground 

 has been allowed to remain wet for long periods. It is also stated that the disease 

 may be produced by heavy applications of nitrogenous manures, followed by irriga- 

 tion close to the trees during hot weather. The scaly bark gum disease is prevalent 

 in southern California. It attacks the trunk of the tree as well as some of the larger 

 branches and if not checked destroys the tree. The new bark is unhealthy and the 

 disease jienetrates to the center of the limb or trunk of the tree. Thus far this forn\ 

 of the disease has not been observed in California on sour-orange stocks, nor upon 

 the pomelo stock. The sour stock has not proved entirely satisfactory in southern 

 California, and it is recommended that pomelo stoc;k should l>e used in its stead. 

 The sweet-orange stock is much more susceptible to the disease. The third disease, 

 die-back, is quite prevalent in some parts of the State. The affected trees make an 

 apparently healthy growth in the spring and sunmier, but the young shoots soon 

 turn yellow, the leaves drop off, and the twigs die back to the older wood, from which 

 a brown granular exudation takes place. In a season or two the older wood also 

 dies. Experiments with fungicides in combating this disease have been attempted, 

 but so far without apjareciable results. It is claimed in most cases that die-back is 

 due to some fault in the subsoil, such as hardpan, marl, or overirrigation. The cor- 

 rection of these evils will, it is believed, tend to prevent the disease. Closely related 

 to the die-back and probably due to the same causes is a disease designated as mottled 

 leaf. It is believed to be a partial chlorosis of the leaves. This disease has been 

 noticed most commonly upon trees grown in soils where the tap roots reach sand or 

 dry gravel, and it is probable that other unfavorable conditions, such as alkali or 

 hardpan, may produce the same effect. 



The fungus diseases of cacao in the "West Indies, A. Howard ( West Indian 

 Bui., 2 {1901), No. 3, pp. 190-211). — This paper gives an account of work already 

 done by the author in studying the cacao diseases of the West Indies, and also brings 

 together the results obtained by some other investigators. The diseases of cacao are 

 grouped under the headings pod diseases, stem diseases, and root disease. At the 

 present time 3 distinct pod diseases have been noted in the West Indies; one is 

 widely distributed and is believed also to occur in South America, while the other 2 

 appear almost entirely confined to Trinidad. 



The brown rot {Diplodia cacaoicola) is a widely spread disease of the pods, and 

 although investigation as to its nature appears to have been undertaken only quite 

 recently the disease is believed to have existed for a long time. Pods attacked by 

 this disease exhibit circular brown spots which gradually extend all over the pod, 

 causing the complete destruction of the rind and its contents. The spread of the 

 disease varies somewhat according to ripeness, but usually the whole pod is affected 

 within 6 to 10 days from the time that the disease first makes its appearance. The 

 microscopical characters of the fungus are described at some length and its parasitic 

 nature was established by means of infection experiments. The fungus has been found 

 living not only on the old husks but also on living pods, dead cacao trees, old prun- 

 ings, and on diseased sugar cane where cane cultivation was carried on among the 

 cacao trc~cs. As remedial measures for the prevention of injury by this fungus the 

 author suggests the gathering of the pods before they become too ripe, as ripe pods 

 seem to be especially liable to attack. All hulls and husks should be buried or 



