FUNGOID PESTS OF CULTIVATED PLANTS. 117 



caused by the Glceosporium. In America it is said that " the affected 

 Apple at first shows one or more black, or usually brownish, spots on any 

 part of the surface ; as these gradually enlarge their shape becomes more 

 or less circular, and their borders somewhat sharply defined, sometimes 

 the spots coalesce, or run together, and in this manner the entire Apple 

 is soon affected. Towards the centre of the diseased spot there is 

 usually a very dark, frequently almost black, discoloration. The darker 

 portions are studded with minute black points, which are slighly raised 

 above the surrounding tissue, imparting to their surfaces a somewhat 

 roughened appearance ; occasionally these points are arranged in circles 

 or grouped in little clusters." 



It is affirmed that the spores when sown in water germinate within 

 ten hours by sending out one or more thickish germ tubes. In about 

 twenty hours they will produce at their extremity globose bodies (8 (j. 

 diam.), more or less dark-coloured, which are of the nature of secondary 

 spores. These secondary spores germinate in like manner, and produce, 

 in a third series, the same kind of bodies as the original primary conidia. 

 So that by an alternation of generations the old type is reverted to. 



In addition to the above it has been announced that thick-walled 

 cavities have been found at the base of the conidia-pustules, which con- 

 tain minute colourless bodies resembling spermatia ; what may be their 

 purpose or destiny is still an open question. No wonder, then, that the 

 Apple growers of the United States have been cautioned that they " have 

 a dangerous foe to contend with," and they are on the alert. 



The fungus is known in Britain, Italy, and the United States. 



The remedies suggested are spraying with a solution of one half 

 an ounce of sulphate of potassium to one gallon of water. Application 

 at intervals of ten days. In some cases the disease was arrested after 

 the first application. Another fungicide applied with success is the 

 ammoniacal carbonate of copper solution. 



Grapes are also liable to the same disease. 



Sacc. Syll. iii. 3751 ; Mass. PL Dis. 281, fig. 75 ; Gard. Chron. 1856, 

 p. 245 ; U.S.A. Dap. Agri. 1890, pi. iii. ; Cooke Hdbk. No. 1411 ; Thiim. 

 Pom. 59; Tubeuf, Dis. 482; Journ. R.II.S. xxviii. 1901, p. G26 ; xxix. 

 1905, pp. 746, 755. 



Apple-tree Antheacnose. 

 ( ' rb.eosporium Malicortis (Cord.). 



Under the name of dead spot or black spot this new disease has made 

 its appearance in various parts of the United States and British Columbia. 

 Branches two or three inches in diameter are usually attacked, and the 

 disease appears first in the autumn. 



Journ. R.II.S. xxviii. p. 233 ; U.S.A. St. Bel. Montana Rep. 1902. 



Insecticides for Orchard and Bush Fruit, see Journ. R.II.S. xxix. 

 p. 816. 



Apple Si-kck. 

 Spilocaa Pond (Fr.). 

 An enumeration of the fungi which attack Apples and Pears would 

 not be complete without reference to two or three obscure species which 



