316 



LIGHT FROM THE SOCIETIES. 



vegetable matter in stable manure furnishing humus 

 could be supplied by turning under green crops. This 

 element gives porosity to soils and renders them more 

 friable. 



It was found that stable manure for peach trees made 

 more wood than commercial fertilizers containing less 

 nitrogen. Home-mixing was favored as admitting of 

 furnishing the elements needed in the proper propor- 

 tion. Cotton-seed meal furnishes nitrogen in a quickly 

 available fcJrm, while muriate of potash is the cheapest 

 medium of obtaining potash, and for that reason prefer- 

 able to the more expensive sulphate, though the latter is 

 credited with imparting improved quality to potatoes. 

 Whether it did so with fruits he was unable to say. 

 Mr. Beebe thought mechanical condition of soils of de- 

 cided advantage in securing the full benefits of commer- 

 cial fertilizers. Judge Strong strenuously urged the use 

 of kainit and odorless 

 phosphate. Four hundr- 

 ed pounds of each per 

 acre on his soil enriched 

 it more than larger ex- 

 penditures for other 

 commercial fertilizers. 

 He advocated the growing 

 of the most paying crops 

 adapted to the soil, and 

 buying supplies of such 

 as could not profitably 

 be raised. — N. /. State 

 Hort. Society. 



A New Destructive 

 Carnation Disease. — Its 

 distribution is already 

 quite wide-spread. It is 

 now known to occur in 

 Massachusetts, Pennsyl- 

 vania, New York, Ohio, 

 Michigan and Indiana, 

 and is reported from more 

 than one locality in most 

 of these states. Probably 

 it has also invaded other 

 states. This rust has 

 long been known in 

 Europe, and is especially 

 common in Italy and 

 Germany. 



The cause is a vege- 

 table parasite Uromyces 

 cai-yophyUiuus, that in- 

 vades the stem and leaves 

 of the plant, and after a 

 time produces a quantity 

 of spores to spread the malady. The first intimation of 

 rusting is the appearance of oblong pustules, a sixteenth 

 to an eighth of an inch long, or even larger, somewhat 

 raised above the surface of the leaf (fig. i, page 315). 

 At first the pustule is covered with the gray outer 



Fig. 1. Ger,min.'\ting Uredo- 

 SPORES. I. Surface View. 

 2. Optical Section. 



membrane of the leaf, but this is soon pushed aside, and 

 a brown or blackish mass of spores is exposed. The 

 spores come away easily, and readily adhere to the hands 

 as a brown dust. The pustules are usually scattered, or 

 somewhat clustered, upon both sides of the leaves and 

 on the stem. Plants sometimes become so covered with 

 the rust that they drop the spores as a dust whenever 

 shaken or handled. 



The fungus that does the harm is inside the leaf or 

 stem. Even under the microscope it can be brought into 

 view only with much difficulty. After a time spores are 



Fig. 4. Section Through a Pustule of Uredospores. 

 produced by thess concealed parasites, which forming in 

 masses soon rupture the surface-covering of the leaf and 

 are exposed to view. 



The spores are for spreading the fungus. There are 

 really two kinds, one for immediate service (uredospores) 

 and one for use after a considerable period has elapsed 

 (teleutopores) (fig. 2, page 315). The only difference the 

 naked eye can detect between them is that the latter are 

 of a slightly darker brown. The uredospores will start 

 to grow as soon as ripe, if placed in water, but the 

 teleutospores will only grow after they have passed a 

 certain period of rest. Growth of the uredospores takes 

 place by pushing out a delicate tube from the spore (fig. 

 3, this page) which reaches its full development in less 

 than twenty-four hours, and dies unless it has in the 

 meantime penetrated a carnation-leaf. If this happens, 

 the tube draws nourishment from the juices of the leaf and 

 branches and ramifies through the tissues, and within a 

 month, possibly in a week or two, is ready to bring forth 

 a new crop of spores. In this way the rust is very rapidly 

 propagated from leaf to leaf and from plant to plant, 

 whenever the atmosphere is moist enough to permit a 

 thin film of water to remain on the leaves a few hours, 

 in which the spores may germinate. The resting spores 

 (teleutospores) do not behave in this way. They germi- 

 nate (probably after some months) upon the ground, 

 forming still more minute sporules, which are borne to 

 the carnation-plant by the wind, and there establish the 

 rust again. 



From this knowledge of the habits of the fungus we 

 may draw some very important suggestions to guide us in 

 fighting it. So far as possible remove the affected leaves, 

 or even whole plants, taking care not to scatter the spores 

 unnecessarily, and burn them., in order especially to 

 destroy the resting spores. Spray the plants with some 

 solution that will check th? formation of spores in the 



