New York Agricultural Experiment Station. 485 



at lifting time as opposed to 100 per cent, of rusty 

 plants in the check. Both of these solutions are readily washed 

 off by rains which were very frequent during July. The adhesive 

 character of Bordeaux mixture is well known. Notwithstanding 

 this advantage possessed by Bordeaux mixture; both copper sul- 

 phate and potassium sulphide proved superior to it in a very 

 rainy season under parallel conditions. It is probable that the 

 latter two fungicides M'hen used indoors, where they are not 

 washed off by rains, will be still more efficient in preventing rust. 

 It is impossible to say, without making further experiments, what 

 degree of success may be expected from the faithful use of these 

 solutions as a preventive indoors, but certainly the prospects are 

 encouraging. The great obstacle to success in this direction is 

 the difficulty of getting the plants through to lifting time without 

 contracting rust. The most critical time in the life of the plant is 

 the period of four months or thereabouts which it spends in the 

 open air. So far as we at present know, there is no way of wholly 

 preventing infection at this period and when plants are once 

 infected we know of no treatment which will cure them. This 

 last we learn from our experiments and from the experiments 

 of Beattie* Plants in the field are constantly exposed to infec- 

 tion from rusty plants in neighboring fields. The vigilant, pains- 

 taking florist who takes all possible care, and at considerable ex- 

 pense perhaps, to prevent the rust from getting a foothold on his 

 place, puts himself at the mercy of his more careless neighbors 

 the day he sets his plants in the field. If there is a field of rusty 

 plants anywhere within a radius of one mile his plants are al- 

 most sure to be exposed to infection. The rust spores, which 

 are produced in immense numbers, are readily carried by the 

 wind. How far spores may be carried in this way is not known, 

 but probably for several miles. Dr. Thaxterf has placed on rec- 

 ord some observations on a case of rust {Roestdia hotrt/opites) 



* Beattie, W. K.. Carnation Rust. Florists' Exchange, Vol. VI., p. 492. 



tTliaxter, R., On Certain Cultui-e.s of Gyinnosporanfjia. witJi Nott^s on Tlieii' Roe.steliu;, 

 Am. Acad, of Arts and Sciences. IHHfi, p 2G(i. Dr. Tliaxter informs iiie that on the Isle of 

 Shoals, off the coast of New Hampshire, he found an abundance of Hnsteiia botri/apites o\\ 

 Anielanchifr whi\e then- were no specimens of C,')(;i/v.s-.s(/.s- ithe hosl-i)lant of Oi/iiinos)ioran- 

 gium bisepUttnm which is genetically connect<'d with R. fco/r(/.'P(7es) near, r than the mainland, 

 eight miles distant. The sporidia of the Gi/iiinoHpordvgiinii mnst have been carried eight 

 miles by the wind. 'I'he evidence here is nion- cmclusive Ilifin in the Insiance above cited. - 



