PESTS OF ORCHARD AND FRUIT GARDEN. 



9 



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 n 

 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 hi. 3751 ; Mass. PI. Dis. 281, fig. 75 ; Gard. Chron. 1856, 

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

 Pom. 59; Tubeuf, Dis. 482. 



Apple Speck. 

 Spilocaa pomi (Fr.). 



An enumeration of the fungi which attack Apples and Pears would 

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

 are reported to have occurred on the fruits. The little black specks upon 

 ripe Apples which resemble fly-spots have not afforded any evidence of 

 fructification. Known under the above name, they are probably only 

 incipient conditions of " Apple scab." 



The Spliceria malorum of Berkeley, found upon decaying Apples lying 

 on the ground, would be outside the bounds of our inquiry, since it is 

 clearly a saprophyte, and possibly only Diplodia malorum. 



In 1878 Baron von Thiimen published a work entitled " Fungi 

 Pomicoli," in which he enumerated thirty-one fungi as growing on 

 Apple and twenty-three on Pear trees, or their fruit. It is consoling to 

 find that the majority of these are in no respect parasitic, and many of 

 them common to all kinds of vegetable matter. Hence it is no guide to 

 orchard pests. 



Ft. Sijst. Myc. iii. 504 ; Thilm. Pom. p. 9. 



