550 EXPERIMENT STATION RECORD, 



supply, and at tbe same time cutting off the roots from tlieir food so that they 

 ultimately die. 



As to treatment, dead or badly diseased trees should be dug up and the butt 

 of the stem, together with 2 or 3 ft. of the part above the ground, should be 

 burned. 



A new disease of citrus fruits, I. B. P. Evans (Transvaal Agr. Jour., 8 

 {1910), No. 31, pp. -'iSS-.'iG'), pi. 1). — A disease of Natal lemons was noticed in 

 1909 in which the fruit was light in weight and brownish colored. Accompany- 

 ing the discoloration was a softening and general translucency of the rind, which 

 at the same time became distinctly sticky. At first it was thought that the 

 disease was due to one of the mold fungi, but subsequent observations showed 

 that this could not be true, for instead of becoming soft and moldy the fruit 

 dried up and the brcfwn discoloration became black. Lemons affected by the 

 disease simply dried out, retaining their original shape and form. 



A study was made of the cause of the trouble and the organism isolated. 

 This proved to be an uudescribed species, to which the name Diplodia natalensis 

 n, sp. is given. 



All varieties of citrus fruits appear to be readily attacked by this fungus, 

 and in addition apples, apricots, and peaches were destroyed by it if spores 

 were introduced by puncturing the skin. 



Observations indicate that the infection of the fruit occurs most commonly 

 at the time of picking, when the fungus gains entrance through injuries. 



The influence of the soil on the development of the roncet of the grape, 

 E. Pantanei.li (Atti. R. Accail. Lined, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser., 

 19 (.1910), I, No. 7, pp. 395-1,01). — After a careful chemical examination of soils 

 from various localities the conclusion is reached that the roncet has no rela- 

 tionship to the presence or absence of any specific element in the soil, but 

 rather that the physical characters of the soil, such as warmth, porosity, loose- 

 )iess, drainage, etc., play an important role. Three groups of factors seem to 

 have an appreciable influence on the appearance of roncet in plants which came 

 originally from healthy layers and scions: (1) The history of the soil both 

 before and after planting, that is, whether it was previously in grapes or other 

 fruit or in grass, etc.; (2) specific properties of the grapes such as depth and 

 extent of the root system, the relation of the rapidity of the growth of the 

 upper parts as compared to the root development, and the specific sensibility to 

 exhaustion of the soil; and (3) position and physical properties of the soil. 



Of these three groups of factors the third has a distributive and predisposi- 

 tional action, the second influences only the time and intensity of the attack, 

 while the first group constitutes the main causal factors, of which experience 

 shows that the most important is sensibility to exhaustion of the soil. 



Two diseases of gooseberries, F. T. Brooks and A. W. Bartlett (Ann. 

 MycoL, 8 (1910), No. 2, pp. 167-185, pi. 1; abs. in Gard. Chron., 3. ser., !,7 

 (1910), No. 1226, p. 7/28).— Attention is called to the death of large numbers of 

 gooseberry bushes in Cambridgeshire in which the first indication of trouble is 

 a wilting of the foliage of one or more branches. The attacked branches then 

 die and finally the entire bush. It is claimed that death is due to two dis- 

 tinct fungi, Botrytls eincrea and Cytosporina ribis. 



In the disease caused by B. eincrea the external characters of the disease are 

 a wilting and subsequent browning of the leaves on a single branch, usually 

 during the spring and early summer, while bursting through the bark at the 

 base of the attacked branches are innumerable tufts or conidiophores of 

 B. cinerea which arise from large black sclerotia located just outside the cylin- 

 der of wood tissue. These dead branches easily break off at the point of union 

 with the main stem. When the branch dies others become affected so that finally 



