120 ANNUAI, RKl'ORT OF THE Off. Doc. 



ll infects pear, quince and apple trees, and is known as pear blight, 

 twig blight, black blight, (runk bliglil, liody blight, bark blight, 

 canker, etc. . 



Treatment: Cut out the diseased twigs and limbs about twelve 

 inches below the diseased tissue. Cut out patches of diseased bark on 

 the trunk or larger liud)s. Sterilize all wounds by painting them over 

 with a strong solution of copper sulfate, one pound to one gallon of 

 water, or corosive subliuiate, one ounce to one gallon of water, or 

 (best) one ounce of formalin in two gallons of water; or paint the 

 cut surfaces with ordinary house paint. 



BLACK KNOT 



This is a most common and unsightly fungous disease, which at- 

 tacks i^lum and cherry trees. It appears on all woody parts of the 

 tree, but mostly (m smaller twigs, first as a slight swelling, and later 

 as a rough, knott}^ excrescence covering the twig from one to five 

 inches. As soon as this knot forms a complete ring about the twig or 

 limb, the nutriment of the tip portion is completely cut off, and it 

 dies. 



Treatment: Cut out aud burn all diseased portions, six or eight 

 inches below the knot, in the spring of the year, and all which may 

 develop during the summer. Paint over the cut ends with a dis- 

 infectant solution (see under Pear Blight) or house paint. Spray 

 with Bordeaux mixture before the buds burst, using three pounds 

 of copper sulfate, five pounds of lime and fifty gallons of water, or 

 with lime-sulfur solution as for San Jose scale, and follow this with 

 a spray of Bordeaux mixture made by using one-half the above 

 quantity of copper sulfate, as soon as the petals drop, and again 

 ten days or two weeks thereafter. 



PEACH YELLOWS 



The condition known as Yellows is probably the most serious 

 affection of the peach and plum. That it is contagious, spreading 

 in all directions from a focus, is well established. For this reason 

 curative measures are not generally recommended. Affected trees 

 should be removed and destroyed, care being taken to avoid bringing 

 them in contact -with healthy trees, as soon as the first definite 

 symptoms of this condition appears. 



The first certain sign of the disease is premature ripening of 

 fruits, which are more or less mottled with red on the outside, and 

 streaked with red within. The sign next in importance in determin- 

 ing the Yellows is the modification of the twig and leaf growth. The 

 leaves of diseased trees will be shorter, narrower, slightly yellow in 

 color, and standing at right angles to the tree. Suckers often grow 

 in the axils of the leaves, which are set more closely together on the 

 twigs than normally. 



