14 



The Florists^ Review 



JiLY 18, 1912. 



Frequently, however, the aflFected plants 

 outgrow the disease entirely and thus 

 a distinct line of demarcation can be 

 made between tiie previously diseased 

 part and the healthy part of the new 

 growtii. At other times infected plants 

 keeji on growing and even flowering, 

 with the disease keeping pace. 



Spread of Mosaic Disease. 



Attempts to culture and to isolate 

 the organism which causes this mosaic 

 disease have failed. Like th& peacji 

 yellows and the mosaic disease of to- 

 bacco and tomatoes, this mosaic dis- 

 ease of the sweet pea, too, can be re- 

 produced by a puncture with a sterile 

 needle from a diseased into a healthy 

 leaf. Yet no organism could be ob- 

 tained in culture, nor can it be de- 

 tected with the microscope. Neverthe- 

 less, this disease is contagious, as is 

 the peach yellows. When this disease 

 tirst made its api)earance in our experi- 

 mental sweet pea field, the diseased 

 areas were immediately located in order 

 to learn something of the spread of this 

 disease. They formed two small areas, 

 one in about the center of the field, 

 the other in the southeast corner. With- 

 in a lapse of ten days another survey 

 was made and the whole field was found 

 to be contaminated. With the excep- 

 tion of the dwarf Cupid varieties, 

 which are seemingly immune, all were 

 found to be affected with the mosaic. 



When first investigating this disease, 

 we thought that perhaps this mottling 

 of the leaves was merely a variegated 

 condition of the leaves. We also 

 thought that perhai)s the curling of the 

 tender tips, as well as the mosaic effect, 

 was due primarily to the ])resence of 

 aphis, which at the beginning of the 

 season was so plentiful. Experiments 

 were then undertaken to determine 

 definitely these jtoints. 



Aphis May Carry the Disease. 



Accordingly, sterile pots with sterile 

 .soil were planted with sterilized seeds. 

 Eacli })ot was isolated in a glass cham- 

 ber and the i)lants were allowed to 

 grow for three weeks, to see whether 

 any disease would develoj) on them. 

 However, these plants remained free 

 from any diseases. These jtots with 

 plants were then divided into four lots. 

 Into lot 1 were introduced a few stem 

 mothers from affected mosaic plants in 

 the field. Into lot 2 were introduced a 

 few stem mother aphis from apparently 

 healthy plants in the field. The plants 

 in lot 3 were ])unctured with sterile 

 needles, first pricking a mosaic affected 

 leaf and then puncturing with the same 

 needle the healthy leaves. Lot 4 was 

 merely punctured with sterile needles 

 and these were designed to serve as 

 checks. In each lot there were pots 

 with ])lants in order to duplicate each 

 experiment. A^ter ten days the lots 

 which were inoculated with the aphis 

 frtfm diseased and healthy plants both 

 began to show the symptoms of mosaic. 

 This would, therefore, seem to show 

 that the mere puncture of aphis would 

 be responsible for the mosaic disease. 

 However, this is not the case, as we 

 will soon see. Moreover, it is easy to 

 suppose, and that on good ground, that 

 the ai)his taken from seemingly healthy 

 plants in an infected field might them- 

 selves have been infected before. But 

 this would be no valid proof. Lot 3, 

 which was infected with needle punc- 

 tures from diseased leaves, began after 

 ten days to show the mosaic disease. 



while the check punctures remained all 

 healthy to the end of the experiment. 

 This definitely proves that the aphis 

 is not the cause of the trouble, but 

 merely the carrier of the mosaic dis- 

 ease. It seems, therefore, that any 

 steps taken to control the aphis may 

 also serve to control the mosaic. From 

 this, too, it seems that not only the 

 aphis, but also any biting or sucking 

 insect, may help to spread the disease. 

 It has been also definitely proved that 

 the mosaic disease is a contagious one, 

 since it can be produced at will by 

 artificial inoculations. 



Origin of Mosaic Disease. 



Your present speaker believes, with 

 Professor T. F. Manns, chief patholo- 

 gist and bacteriologist of our Dela- 

 ware Experiment Station, that the 

 mosaic disease is caused by a protozoic 

 organism which neither our present 

 microscopes nor our present cultural 

 and staining methods are sufficient to 

 detect. The symptoms produced in arti- 

 ficial inoculations of this disease are 

 similar to those in the field; namely, a 

 yellowish spotting or mottling of the 

 leaves and a tendency of the leaves of 

 the tips of the plant to curl. Judging 

 from all our observations, it does not 

 seem probable that this mosaic disease 

 of the sweet pea is either introduced or 

 carried with the seeds. The mosaic 

 disease has not once made its appear- 

 ance in the laboratory during two 

 years ' work on the sweet pea diseases, 

 and in sowing both sterilized and un- 

 sterilized seeds were used all the time. 

 However, it must be added in this 

 connection that we have always used 

 sterilized pots and soil. This at once 

 suggests the possibility of the soil be- 

 ing the source where the organism is 

 harbored. On this i)oint we are now 

 working. Should we find that the soil 

 harbors the organism, then we shall 

 be on the road toward discovering some 

 jneans of treatment. 



The Streak Disease in England. 



In England the sweet peas suffer from 

 a disease known as streak. This dis- 

 ease is much dreaded by the English 

 gardeners, as it causes great losses. 

 From the descriptions given of the 

 disease, it seems to be similar to the 

 new mosaic disease of this country. 

 However, we refrain from j)assing 

 final judgment until we have the op- 

 portunity of seeing the English speci- 

 mens and of making comparisons. In 

 England the streak disease is attrib- 

 uted to a fungus, Thilavia bassicola, 

 which attacks the roots. In our investi- 

 gations we have not found the thilavia 

 fungus or any other organism associ- 

 ated on the roots of mosaic affected 

 j)lants. In fact, such affected plants 

 were found to have as normal a root, 

 with as much legume nodules, as the 

 healthy ones. If our mosaic disease 

 proves to be the same as the streak 

 disease of England, it will be safe to 

 assume that the thilavia in England 

 is secondary and merely follows the 

 already weakened mosaic affected 

 plant. 



[To bo Continued.] 



Grand Bapids, Mich. — Peter Ouster- 

 house, formerly of Greencastle, Ind., is 

 now at 1419 North La Fayette street, 

 in this city, where he has established an 

 agency for greenhouse supplies and 

 greenhouse real estate. 



OBITUARY. 



August Dresel. 



Another of Chicago 's pioneer florists 

 passed away at 6 a. m. Wednesday, 

 July 17, at Crown Point, Ind. Mr. 

 Dresel had been ill for some time, 

 but the end was sudden. 



August Dresel was 74 years of age. 

 born in Germany. He came to Amer 

 ica as a young man and, after brief 

 employment in the trade at other 

 places, reached Chicago in 1865, almost 

 immediately starting in business for 

 himself. He carried on the green- 

 houses on West Belmont avenue for 

 thirty-five years. When he started he 

 was far out in the country, but the 

 city grew up around^him and at length 

 the changing conditions made the 

 greenhouses no lonw^r profitable. They 

 were closed out in3l901. Shortly after 

 Mr. Dresel made alaew start at Crown 

 Point, Ind., doina business as the 

 Crown Point FloraaCo., August Dresel, 

 manager. Here he grew both cut flow- 

 ers and plants for the wholesale trad© 

 and has for ten years done a pros- 

 perous business. He is survived by 

 a widow and fit^e children. Two of 

 the sons are in the trade, August, Jr., 

 with S. J. Pearce, the well-known Chi- 

 cago grower, and Henry, with a firm 

 at New Orleans. 



Carl Michler. 



Carl Michler, a florist of Lexington 

 Ky., died July 5 at the Good Samari- 

 tan hospital, in that city, after a lin- 

 gering illness. He was 69 years of 

 age. He was born in Germany and 

 had lived in Lexington for many years. 

 He is survived by his wife, one daugh- 

 ter. Miss Rose Michler, and four sons, 

 George J., William, Louis and Charles, 

 all of Lexington. 



George M. Boak. 



George Martin Roak, one of the 

 most widely known ^orists in the state 

 of Maine, died July 7 at his home on 

 High street. Auburn, Me., after an 

 illness of three years. He was born in 

 the city of Auburn and had always 

 lived there. He was 64 years of age 

 and went into business in Auburn in 

 the year 1874. He belonged to a num- 

 ber of social and secret orders and was 

 a hard worker in these orders. 



He is survived by his wife, Emma D.^ 

 Roak; six daughters, Mrs. F. E; Don- 

 nell, of Whitman, Mass., Mrs. James 

 F. Boag, of River Forest, 111., Mrs. J. 

 L. Snell, of Lynn, Mass., Mrs. V. S. 

 Darling, Misses . Emma, and Mabel 

 Roak, of Auburn; two sons, Hugh and 

 Ralph, both of Auburn; two sisters, 

 Mrs. H. B. Pulsifer, of Auburn, and 

 Mrs. H. C. Little, of New York, and 

 one brother, J. H. Roak, of Boston. 



Johnstown, N. Y. — William Lar- 

 combe, of 129 East Main street, has 

 l)laced an order with the King Con- 

 struction Co. for the materials for a 

 new greenhouse, 35x100 feet. It will 

 be erected at once and will be used for 

 roses and carnations. 



Nashville, Tenn. — Joy & Sons Co. has 

 been shipping a big crop of gladioli to 

 Chicago, where Thomas Joy visited last 

 week. At the greenhouses the company 

 has been employing between eighty and 

 ninety men in getting ready for the 

 new season. The regular force consists 

 of about sixty men. 



