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The Apricot Disease. 

 By F. S. Ceawtoed. 

 rEead November 4, 1884.] 



Two years ago I forwarded to Dr. M. C. Cooke leaves and 

 fruit of the apricot — the former attacked with the " Shot-hole 

 Fungus," and the latter with the pustular disease on the fruit, 

 both which have been so common of late. I likewise mentioned 

 that I thought there was a relationship between the two fungi. 

 In reply Dr. Cooke stated that the shot-hole fungus was I'hyl- 

 losticta cwcumcissa, and the pustular disease was caused by 

 Hehnintliosporium rliabdiferum, and that the two fungi were 

 entirely distinct. 



Observations made during the last and present seasons have 

 strengthened my suspicions that the two fungi are connected, 

 and this opinion has been confirmed during the last few days 

 by discovering several specimens of the shot-hole fungus on 

 almond leaves in a state of fruit, the spores of which are pre- 

 cisely similar to those of the apricot fruit fungus, and which in 

 shape resemble an Hehnintliosporium , and not a Phyllosticta. 



In spite of the prevalence of the shot-hole fungus on the 

 almond, cherry, plum, apricot, &c., it is a rare thing to find it 

 showing spores. One day I discovered several spots on an 

 almond leaf abounding with spores, but the next day failed to 

 find any after a prolonged search, although to the naked eye 

 the spots seemed precisely similar, and the leaves were taken 

 from the same part of the tree. This may be owing to either 

 the fruit spores growing very rapidly, and as quickly falling 

 off, or else that a spore falling on a leaf gives rise to a myce- 

 lium, which grows, making the characteristic brown spot that 

 soon drops from the leaf, but which only under exceptional 

 circumstances produces spores in that stage of its existence. 



In looking over Dr. Cooke's letters I am inclined to think 

 that in naming the shot-hole fungus a Fliyllosticta an error 

 was accidentally made, because several other fungi were for- 

 warded at the same time, and it was quite possible that one 

 was a JPhyllosticta ; and as P. circumcissa, according to Cooke, 

 makes shot-holes in the leaves of many plants, the mistake 

 might thus easily arise. I also wish to point out that Selmin- 

 thosporiiim rhahdiferum, according to "[British Fungi," is found 

 on ripe peaches, whereas I have never seen a peach, ripe or un- 

 ripe, attacked with the " pustular eruption," although the 

 leaves are to a slight extent affected with the " shot-hole " 



