1907.] 



Cherry Leaf Scorch. 



341 



orchard on quite good cherry ground, it recurred annually, 

 and in 1906 the trees were decidedly more diseased than they 

 had been previously. It is hardly to be doubted that if a 

 season comes specially favourable to the fungus it will invade 

 to some extent the famous orchards of Sittingbourne and 

 district, the fungus spreading from the large tract of badly 

 diseased orchards close to them on the south. 



Nearly all the varieties of sweet cherries, e.g., Frogmore 

 Bigarreau, Waterloo, Clusters, Eltons, Blackhearts, are liable 

 to be attacked by cherry leaf scorch, but acid cherries (such as 

 the Flemish, Morello and May Duke) have so far proved quite 

 immune to the disease, even when growing in the midst of the 

 worst affected orchards. Among sweet cherries, however 

 it is interesting to find that two varieties have proved in several 

 orchards to be either wholly immune, or almost immune, 

 to the disease ; these are the Turk and the Napoleon. In one 

 orchard of about three acres, alternate rows of Turks and 

 Waterloos had been planted. The trees are now about sixteen 

 years old ; about five years ago the disease appeared on the 

 Waterloos, and steadily increased each succeeding year, until 

 scarcely a single leaf fell from the trees in the autumn, and the 

 cherries themselves were ruined through the fungus forming 

 blackish " scabby " spots in the flesh. These Waterloos have 

 now been cut down and regrafted. During the whole time, 

 i.e., through the five years while the disease spread and was at 

 its worst, the Turks remained practically free from the disease. 

 In another locality a number of Frogmore Bigarreaus suffered 

 from the disease continuously for fifteen years until they were 

 quite useless and nearly dead ; during these years the 

 Napoleons in the same orchard remained quite free. The 

 resistance to disease of certain varieties is a fact of considerable 

 importance in connection with the regrafting of diseased trees. 



As I have personally observed, the wild cherry (Prunus 

 avium) is sometimes attacked, and trees may occasionally be 

 found in woods (usually near the outside) and hedges with 

 dead leaves, bearing the fungus, hanging on the boughs through 

 the winter months. The fruit of such diseased wild trees may 

 be severely attacked, as was the case this season with trees in 

 Olantigh Park, near Wye. Such wild trees, however, appear to 

 be capable of throwing off the disease in a year or so, while 

 the cultivated varieties of the cherry are often not able to do so. 



