105 



and that in other countries where it has been tried the plant will produce so many 

 full-formed berries as to depreciate its value as a currant crop. 



The plant has long been introduced into California and is advertised for sale by 

 various nurserymen throughout the State. 



LIME WASH FOR TREES. 



E. D. S., Steuben County, New York. I am told that the Department recommends 

 the whitewashing of fruit trees as a cure for blights, yellows, and other diseases. If 

 this is true, may I ask what this wash consists of, and how applied so as not to injure 

 the tree. Will not the clogging of the pores in the bark of the tree by a coating of 

 lime or other wash do more harm than good? 



Some of my apple and pear trees have blighted to some extent, but I have seen it 

 stated that washing the bark of trees has no effect, either as a preventive or as a 

 cure for blight. Can you inform me on this point ? 



Answer. The reports of this Department have nowhere recommended whitewash- 

 ing as a cure for "yellows and other plant diseases," but frequent mention has been 

 made of the application on pear and other trees as a preventive of blight, at least on 

 the parts covered with the mixture. No harm need be feared in regard to clogging 

 the pores in the bark, as there are no pores in the bark that can be harmed by the 

 application. 



The wash is prepared by placing one-half bushel of lime and 8 pounds of powdered 

 sulphur in a vessel of any suitable kind, covering with boiling water to properly 

 slacken the lime. 



The mixture is applied with a brush, covering all parts of the tree that can readily 

 be reached. The most potent ingredient of the wash is the sulphur. The heat of the 

 sun acting upon the wash evolves sulphurous gases which are fatal to bacteria and 

 microscopic fungi, which, as has been demonstrated, are active agents in blight. It is 

 well known that these microscopic spores are destroyed by sulphurous gases and heat 

 is required to evolve them. Sulphur applications are often made for the destruction 

 of mildew on roses and on other plants, but the efficacy of the sulphur depends upon 

 its connection with a certain degree of heat ; but it must not ignite. The gases of 

 burning sulphur are fatal to the higher order of vegetation and are speedily destruc- 

 tive to all plants. 



Those who have used this lime and sulphur wash on their orchard trees are pleased 

 with the results and have faith in its efficacy in preventing blight. 



But it is well to keep in view that, while blight will not maintain on the portion 

 covered with the wash, the fumes of the sulphur may not be sufficient to prevent blight 

 on the extreme points of branches which can not be reached with the brush. If 

 blight is discovered on a twig or on a branch it should be removed without delay. 

 With this attention and covering the main branches with the wash losses from 

 blight need not greatly be feared. 



RHUBARB. 



N. E. C., Walton County, Georgia. I am anxious to purchase a small quantity of 

 seed of the true medicinal rhubarb. If you will .kindly inform me of its botan- 

 ical name and where it can be obtained, and anything you may know about its cul- 

 ture or preparation for market, you will place me under great obligations. I want 

 the best Turkey rhubarb, or the best commercial kind. 



Answer. Efforts hitherto made by the Department to procure seeds of the best 

 medicinal rhubarb have not been successful. It appears that medico-botanists differ 

 in opinions as to the species of rhubarb which yields the best medicinal root ; on the 

 other hand, it has been stated that the roots of the common kinds, grown for culinary 

 purposes under the name of pie- plant, yield good medicinal roots, and that much of 

 the article in commerce comes from this source. 



