DISEASES AND ENEMIES OF FRUIT. 



845 



year. But on personal examination of the trees it was found that only the trunk up to the 

 branches was washed, and this, of course, could have no influence on the parts not covered 

 by the wash &quot; 



Washing the branches with solutions of potash, lime, copperas, soft soap, or carbolic 

 acid, is often used with good effect in stopping the progress of the blight in its early stages. 

 The washes previously recommended are also regarded by many fruit growers as a preventive 

 of the blight, if applied quite early in the spring. Soils that are very wet should be avoided; 

 also manuring too heavily where the land is already quite rich, lime, wood ashes, or bone 

 dust being better under such circumstances than barn-yard manure. Heavily mulching the 

 trees during the summer and fall is also excellent. Unless trees affected with the blight 

 receive prompt and thorough attention, the disease will be liable to spread rapidly. 



Black Knot. This is a disease that attacks apple, plum, and peach trees, and is char 

 acterized at first by an irregular swelling on the limbs or trunk of a tree, which continues to 

 increase year by year until it cracks, and resembles irregular black lumps, with a hard, 

 uneven surface. This stops the circulation of the sap upwards, and seems to poison the sap 

 that is disseminated downward, causing the whole trunk to become diseased. The cause of 

 this evil is supposed to be the work of an insect. The best remedy that has ever yet been 

 found is to cut away all affected limbs a few inches&quot; below the limit of the disease. When it 

 appears upon the trunk or largest limbs, it will have to be cut or dug out, and care taken to 

 remove every particle of diseased wood. 



The wound should then be washed with a solution of chloride of lime, or spirits of tur 

 pentine, to prevent the farther growth of the fungus, and afterwards (if the limb be large), 

 covered with shellac varnish, liquid grafting wax, or paint. 



Borer. There are various species of borers that attack apple, pear, quince, cherry, 

 peach, and other fruit trees by entering the tree near the ground (usually just below the sur 

 face), and cutting their way through the wood and under the bark, sometimes completely 

 girdling a tree. They are dangerous enemies of fruit trees, their presence often not being 

 detected until the tree is nearly destroyed. The eggs are laid under the loose portions and 

 scales of bark, the insects commencing to eat through the bark almost as soon as hatched. They 

 remain and feed upon it for several months, and finally work their way into the wood. This 

 stage of their progress may be detected by the powder that is seen coming from the bark 



where they are at work. 



The round-headed apple-tree borer (Saper- 

 da Candida) is one of the most injurious to 

 apple orchards, being rivaled only by the 

 flat-headed borer ( Chrysolothris femorata). 

 According to Prof. Eiley this insect remains 

 in the tree three years from the time it is 

 hatched. Mr. D. B. Weir of Illinois, who 

 has made a thorough study of this species, says : 

 &quot;As soon as hatched the young grubs 

 begin to gnaw their way into the bark of the 

 D-HEADISD teer by means of strong, sharp laws. They 



BE BORER. * J 



do not usually penetrate directly through, 

 but reach the liber or inner bark half an inch distant from the point of entrance. In their 

 passage through the bark they shove their excrement and refuse out through the opening of 

 their burrow, and being of a glutinous nature it collects around its mouth in a mass as large 

 as half a bean, or in the shape of a tear. These excretions are usually of an orange color, 

 and are at once recognized by the experienced eye. 



SAPERDA CANDIDA. 



a, larva. 



S. BIVITTATA. 



6, pupa. 



THE ROUND-HEAD 

 APPLE-TREE 



c, beetle. 



