NEW YORK EXPERIMENT STATION BULLETINS. 



THE HOLLYHOCK RUST. 



Until 1886 the United States appears to have been free from this fatal 

 visitant of the European hollyhock gardens. It appeared in eastern 

 Massachusetts in that year, as recorded by Professor Farlow of Harvard, 

 and was an undoubted immigrant from Europe by means of imported 

 seed. 



In 1889 it was sent me from Geneva, N. Y., by Dr. Emery, then of the 

 New York experiment station, and in 1890 appeared abundantly in Ithaca. 

 It has been sent in from other places in this state, but it has not appar- 

 ently become prevalent in the Mississippi valley and westward. 



Although it is not as yet a serious menace to gardeners in America, 



nevertheless they would do well not to neglect this warning of its approach, 



and ought, it seems to us, to make every effort to bring it early under con- 



*trol, before the soil or neglected gardens become abundantly supplied with 



spores, and thereby sources of infection. 



As a lesson for us, the experience of the old world may be very useful. 

 The hollyhock rust in question appeared in Europe about 1869, spread 

 over England and the continent in a few years, increasing to such an 

 extent that the cultivation of the choice varieties of these beautiful flow- 

 ers entirely ceased in many localities, thus entailing great losses, the 

 magnitude of which, in the aggregate, was never fully known. 



It affects the host-plant after this manner: In places where it has 

 become established it appears in May and June on the leaves, stems and 

 petioles of the host, having apparently wintered on the radical or root 

 leaves. Externally it is seen in spots or sort, which are yellow at 

 first. As seen on the under side of the leaf, they soon become wart- 

 like and brown, or even gray, and consist wholly of two-celled spores. 

 These sori, and the mycelium within the leaf from which the sori spring, 

 may so increase as to cause the leaf to wither, dry up and appear as if 

 scorched by fire, long before the time for the appearance of the flowers. 

 Indeed, in many cases no flowers ever appear. Where the attack is not 

 severe, these sori may remain and the leaves continue green until the 

 latter fall in the autumn. 



Several remedies for the disease were at last found effective by European 

 growers, and that given in the Gardener 's Chronicle for 1874, p. 243, is 

 added below: 



Permanganate of potash, (Sat. Sol.), 2 tablespoonfule. 



Water '_ 1 quart. , 



Apply to the spots and all diseased parts with a sponge, and not a syringe or 

 sprayer. 



