PROTECTING PLANTS 



179 



rusty appearance, due to the development of the spores or 

 fruiting bodies. Fig. 211 illustrates the ravages of one of the 

 parasitic fungi, the shot- 

 hole fungus of the plum. 

 Each spot probably rep- 

 resents a distinct attack 

 of the fungus, and in this 

 particular disease these 

 inj ured parts of tissue are 



liable to fall out, leaving 211. Shot-hole disease of plum. 



holes in the leaf. Plum leaves that are attacked early in the sea- 

 son by this disease usually drop 

 prematurely; but sometimes the 

 leaves persist, being riddled by 

 holes at the close of the sea- 

 son. Fig. 212 is the rust of the 

 hollyhock. In this case the 

 pustules of the fungus are very 

 definite on the under side of the 

 leaf. The blisters of leaf-curl 

 are shown in Fig. 213. The 

 ragged work of apple-scab fungus 

 212. Hollyhock rust. jg shown in Fig. 214. 



The constitutional and bacterial diseases usually affect the 



whole plant, or at least large portions of it; and the seat of 



213. Leaf-curl of peach, due to a fungus. 



