I 



THE QUESTION BOX. 



I. Hollyhock Disease. — Enclosed please find leaf 

 ef hollyhock plant ; we should like to know what the 

 disease is in same, and the remedy, if there is any. 

 Any information you can give us regarding same will be 

 appreciated. — P. & W. 



The hollyhock leaf sent by the correspondent is cov- 

 ered on the under side with bright brown wart-like 

 growths — a kind of rust ; and one of these warts dis- 

 sected under the microscope, or examined in cross- 

 section, proves to be composed of spores resembling, in 

 a general way, the spores of wheat rust. It is, in fact 

 one of the true rust fungi, and is known as Piiccinia 

 malvacearum. This species has a remarkable history. 

 It grows only on malvaceous plants, and was first dis- 

 covered in Chili some fifty years ago, being found there 

 growing on some wild plant of this family. In later 

 years, it was, by some means, introduced into Europe, 

 where it attacked the hollyhocks, doing wide-spread 

 damage. In 1873, it made its way into England, and 

 two years later it was first observed in Ireland on plants 

 raised from English seed. It was expected to again 

 cross the ocean and appear in North America years ago, 

 and its occurrence was announced a number of times, 

 but each time the fungus proved to be not the true 

 hollyhock rust, but a related species. In 1886, however, 

 it actually appeared in Beverly, Mass., on malvaceous 

 plants raised from European seed. The next year it was 

 observed on hollyhocks in Boston Public Garden, Cam- 

 bridge and Nahant, and in 1888 specimens were sent 

 from Western New York. It grows, also, on the round- 

 leaved mallow [Afalva rdundifoHn). 



The Gardenei-s' Chronicle for August 22, 1874, p. 243 

 recommends as a remedy Condy's patent fluid (green) 

 in the proportion of one teaspoonful to a quart of water. 

 The writer found that this killed the spores in twelve 

 hours, which was shown by their turning black. Double 

 this strength caused instant death to the fungus, as 

 stated, without injuring the hollyhocks. Sponging is 

 better than spraying. As a preventive measure, set the 

 plants far apart, so that they will have plenty of light 

 and air. Too much shading and dampness favor the 

 rust. It was feared that the hollyhock rust, when it 

 reached this country, would attack the cotton plant, to 

 which it might cause great destruction, but it has not 

 done so, and it now seems probable that it will not. 



There are two other kinds of rust that grow on malva- 

 ceous plants in the United States. Piiccinia malvastri 

 grows on Malvastrum coccineum, and other species, and 

 is quite similar to the hollyhock rust, though specifically 

 distinct. It is found chiefly or entirely (?)west of 

 the Mississippi. Piiccinia heterospora is a very different 

 species as to the form of the spores. It grows on a 

 number of malvaceous weeds and other plants, as Lida 

 spinosa, Abtitilon Aircenncc, etc., occurring in Illinois, 



Kentucky, southwest to the Mexican border, southward 

 into South America, and even to Australia and Ceylon. 

 It is this species that is now thought to be most threat- 

 tening to the cotton plant. — A, B, Seymour, Cambridge^ 

 Mass. 



2. Heating Hot-Beds. — I noticed the request 

 (March, p. 185) to hear your readers' experience with 

 heating material for hot-beds other than manure. 



The principal florist (Neubronner), and also a lead- 

 ing market gardener, of Ulm, Germany, have used, 

 with great success, the refuse from cotton mills 

 and other factories where cotton is worked. They 

 bought it in a neighboring city (Augsburg) at a low 

 price. Before putting it into the beds, they moisten it 

 thoroughly. It a short time it will heat violently, and 

 this heat will last until the whole matter is burned to a 

 fine dust, like ashes. It will give a better heat than 

 horse manure, and its heat will last three or four times 

 as long as that of manure. Its only fault and inconve- 

 nience is that fine dry dust, which will, when the beds 

 are opened and the ground put out in autumn, fly 

 around in the air and be very troublesome. Perhaps 

 this can be overcome. We have never practiced this 

 method because we cannot obtain the material here. I 

 presume it is plentiful in the New England states. — Fr. 



WiNDMILLER. 



Fire Hot-bed. — I have used a fire hot-bed the past five 

 years with good success. I have had no trouble in keep- 

 ing it warm through the coldest weather of March, in this 

 northern country, without blankets, mats, or anything 

 but the common hot-bed sash. It is cheaper and easier 

 run than the manure bed. I never have got up nights 

 to build a fire, and I use oak wood only. — M. F. Ham- 

 mond, Wis. 



3. Prices for Petunia Seeds. — Will you quote 

 prices paid to American growers of finest strains of 

 hybrid superbissima petunias ? also, of intus aurea, 

 intus nigra. Prince and Princess of Wurtemberg, and 

 finest fringed double ? Inquiries from various wholesale 

 seed dealers, also from parties from whom stock is pur- 

 chased, fail to elicit any response. — Mrs. Thomas Gould. 



4. Pea Mildew.- — What will prevent mildew on 

 peas ? Our late peas are so badly mildewed that I have 

 quit trying to grow them ; early peas are not troubled 

 by it. I had thought of trying the Bordeaux mixture. — 

 Wm. C. Cusick, Oregon. 



The pea mildew, of which Mr. Cusick writes, is pre- 

 sumably Erysiphe coiumiinis, one of the so-called "pow- 

 dery mildews " belonging to the same family with the 

 powdery mildew of the grape [Unciniiia spiralis). I 

 have found it abundant and destructive to late peas in 

 Western Massachusetts, and it has been sent me in 

 quantity from Alabama. It is one of the fungi which 

 grow entirely on the surface of the host-plant, covering 



