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The Plum-Rust in England . 
the Plum-Rust as it occurs in England, as well as in Russia and 
the United States. 
During the last two years there have been severe epidemics of 
Plum-Rust in the fruit-plantations of Cambridgeshire, the attack 
last year being so severe as to cause premature defoliation of a large 
number of trees. Hitherto there has been doubt as to the manner 
in which the Plum Rust survives the winter in this country. Both 
uredospores and teleutospores are produced on Plum-leaves affected 
by this fungus. Experimental proof is lacking that the sporidia 
formed by the teleutospores or resting spores which survive the 
winter can infect the leaves of the Plum the following season. 
Indeed such a result is improbable now that we know that the 
Plum-Rust is a heteroecious Eu-form, for the function of the 
sporidia is to infect species of Anemone. It is likely, however, that 
the uredospores from a means by which the fungus may survive 
the winter, for Tranzschel has shewn that uredospores of the Plum- 
Rust kept over the winter at St. Petersburg are capable of 
germinating the following season. But it is yet uncertain whether 
this is a frequent means of propagation from season to season. 
Furthermore, if re-infection the following year were due exclusively 
to uredospores formed in the previous year one would rather 
expect Plum-Rust to develop soon after the foliage had appeared, 
whereas Plum-Rust is frequently not in evidence until the 
summer season is well advanced. 
The experiments detailed above shew that there is another 
means by which this fungus can survive the winter and cause 
infection the following year. Anemone coronaria is a plant frequently 
found in gardens and the mycelium of JEcidium punctatum is 
perennial in its tissues. Thus a plant of Anemone coronaria, once 
it has been affected by this rust, gives rise to crops of uredospores 
year after year, so that a few plants attacked by this aecidium are 
sufficient in themselves to account for the recurrence of Plum-Rust 
year after year. After the first crop of uredospores of the season 
has been produced on Plum-leaves there is every facility for the 
fungus to spread, because by analogy with other Rusts, successive 
crops of uredospores may be produced about every fortnight under 
favourable conditions. 
It is obvious that the eradication of plants of Anemone coronaria 
affected by this aecidium will be of assistance in the control of this 
very common Rust. 
June, 1911. 
