250 ELEMENTS OF AGRICULTURE 



The control of this disease is not easily accomplished. 

 The bacteria kill or blight the young shoots on the body 

 or larger limbs, passing from these to the bark about 

 their bases. Here they form the cankers in which they 

 pass the winter. These cankers offer the most hopeful 

 point of attack. With a sharp knife, remove the canker, 

 cutting well back into the healthy bark. Scrape out the 

 diseased bark, cleaning the wound thoroughly, Sponge 

 the wound with corrosive sublimate solution, one part to 

 1,000 parts water. When dry, paint thoroughly with 

 heavy lead oil-paint and keep painted until healed over. 

 The diseased limbs and twigs in pear trees should be re- 

 moved promptly whenever discovered, and frequent in- 

 spections should be made. Always disinfect cut surfaces; 

 this is absolutely necessary for success. 



Among the bacterial diseases of plants may be mentioned 

 bacterial blight of beans, cucumber wilt, crown gall of 

 apples, peaches, pears, etc., soft rot of turnips, black rot 

 of cabbage, and many others. 



. Fungous Diseases 



228. Characteristics of Fungi. Fungi are very different 

 from bacteria, though they too are plants. Their vege- 

 tative portion consists of branching, root-like threads 

 called mycelium (Fig. 129). Many of them are sapro- 

 phytes, that is, they live on dead or decaying plant or 

 animal remains. Others are parasites, which means that 

 they take their food from the tissues of living plants or 

 animals. Fungi, as well as bacteria, differ from the plants 

 with which we are commonly familiar, in the absence of 



