No. 6. DEPARTMENT OF AGRICULTURE. 791 



from the plants about six inches to three inches from the base of the 

 pJaut, these same plants, when they start to make a new growth, will 

 grow without the slightest sign of black spot, and it is not until the 

 month of tSeptember, when the growth made is from three or tour feet 

 high and densely clothed with leaves, that signs of this dread disease 

 reappears; and then the cause is no doubt on account of some indif- 

 ferent treatment given the rose, or some climatic conditions favoring 

 the development of the fungus that science has not yet been able 

 to detect in time to ellectively stop, and it is found that the more 

 luxuriant are the plants in the autumn months the more liable are 

 they to this disease. 



The plan followed and the safest, is to pick off and destroy by fire 

 every affected leaf as soon as seen. If the plants can be safely 

 carried through the late summer and early fall months without 

 showing signs of black-spot, the danger is not so great, es- 

 pecially after the heating in the rose-houses has commenced, 

 for little or no trouble will be experienced with it during the winter 

 until firing is stopped in the spring, when it is again liable to appear 

 at any time. And when it does make its appearance at the season of 

 the year indicated, it spreads with great rapidity, being very difficult 

 at that season of the year to combat. It is believed that the dew or 

 any form of moisture upon the leaves and in the atmosphere favor 

 (he propagation and development of these disease germs, and as 

 water must be directly applied vigorously to the underside of the 

 leaf where that troublesome plant pest, the insect-mite known as red 

 spider, takes refuge for self-protection, and as the water remedy rec- 

 ommended which is the only known method to dislodge him adds 

 greatly to the moisture produced, it is readily realized how difficult 

 it is to give water sufficient for all the needs of the plants and yet not 

 enough to encourage the black spot scourge. 



There are other diseases to which the rose is subject, but mildew 

 and black spot are the most prevalent and those which give the most 

 trouble and anxiety. 



Carnations when grown under glass are liable to have quite a 

 number of diseases. The one about which so much was said and 

 which caused so much anxiety some ten years or so ago, was 

 the so-called Bust ( Uromyces cari/ophyUinas)^ but it does not possess 

 the same terrors as it did at that time. In appearance it resembles 

 smut in grain, the difference being that the black or dark brown dust- 

 like material appears on the upper surface of the leaf and looks as 

 though it were a bursted blister. 



One which has caused, and ie causing some anxiety to-day, is what 

 was at one time known as Bacteriosis^ now known under the scientific 

 name of Stlgmonose^ and is the result of punctures by insects which 

 are liable to infest Carnations. The insects responsible for this 

 "puncture disease," are the most common of all plant-lice, namely, 



