78 HATCH EXPERIMENT STATION. [Jan. 



it is now doing. At least two have been previously known. 

 The leaf spot (Septoria sp. and Phyllostica sp.) was first 

 described by Professor Halsted of the New Jersey Experi- 

 ment Station several years ago, and occasions more or less 

 damage. The mildew (Erysijihe Cichoracearum D. C.) 

 has appeared more recently, and is rapidly increasing. This 

 has a history very similar to that of the rust under consider- 

 ation, being very common on Helianthus and Artemisia, as 

 well as many other plants. 



We can make no definite reconnnendations at })resent as 

 to a treatment for this rust, it having been reported so late 

 in the year. The true rusts are notoriously difficult to com- 

 bat ; the most so, perha})s, of any class of diseases. Many 

 methods of treatment have l)een tried, l)ut few with deci- 

 sively profitable results. That })anacea of plant diseases, the 

 Bordeaux mixture, has l)ccn fre(]uently recommended and 

 tried for various rusts, Avith widely varying results. The 

 same can be said of another common fungicide, the ammo- 

 niacal copi)er carbonate. Stewart, of the New York Experi- 

 ment Station, reports, in the case of the carnation rust 

 (Uromjxes Caryophyllinus (Schrank) Schrt.), that a solu- 

 tion of potassium sulphide, one ounce to one gallon of water, 

 was most effective. This strength might injure chrysanthe- 

 mum leaves. One ounce to four or five gallons of water 

 would be safer, but not, of course, as effective. With the 

 hollyhock rust (Puccinia Malvacearum, Mont.), a very 

 destructive disease, IVIr. H. L. Frost of Arlington informs 

 us that he has tried the Bordeaux mixture and also the com- 

 mercial fungicide called " Fostite," with results in favor 

 of the latter. It is possible, then, that some of these sub- 

 stances may be effective in preventing this chrysanthemum 

 rust, but we cannot vouch for it. It would certainly be 

 advisable to spray the plants occasionally with the Bordeaux 

 mixture or with potassium sulphide, comritenciny in the sum- 

 oner, when they are young and before any disease appeal's. If 

 the plants are healthy when put into the house, one or two 

 sprayings thereafter should be sufficient to carry them through 

 the season. All plants known to be diseased should be 

 removed and burned. 



We would urge any grower who has been troubled with 



