GENERAL PRACTICE. DISEASES. 237 



early in spring at the rate of 2 ounces per square yard, repeating the dressing imme- 

 diately the fruit is set. If the trees are weakly use the following : steamed bone-meal, 

 4 pounds ; nitrate of potash, 4 pounds ; sulphate of iron, 1 pound ; mix, and apply 

 similarly to the preceding mixture. Trees grown under glass should be top-dressed in 

 advance of their growth, following with the second application soon after the setting 

 of the fruit. In either case add sulphate of lime, equal to all the ingredients where 

 there is a deficiency of lime ; but a dressing of quicklime should be given in all cases 

 of a deficiency of that substance in the autumn, pointing it in and mixing with the soil 

 as deeply as the roots admit without disturbing them. 



When trees under glass are badly affected with gum, they must be carefully lifted, 

 and the roots placed nearer the surface, in fresh soil. The growths must be kept thin, 

 air freely admitted, and the syringe laid aside. If the growth be stunted, or lean and 

 long-jointod, spray with a solution of sulphate of iron, at the rate of a quarter of an ounce 

 to the gallon of water, in the evening when the trees have set their fruit, or when the 

 young shoots are about 2 inches long, repeating at intervals of 15 to 21 days up to the 

 fruit taking its last swelling for ripening. This assists old bark to swell, invigorates 

 the growth, and proportionately increases the size of the fruits. Acting antiseptically, 

 wounds heal over sooner, and Coryneum spores cannot germinate. Trees generally in- 

 fested with gum disease may be sprayed with carbonate of copper in suspension (see 

 "Apple Scab," page 241). Spraying should commence when the fruit is set, and the 

 young shoots 1 to 2 inches long, repeating two or three times at intervals of 12 to 15 

 days, or until the young wood becomes rather firm, when it is proof, without damage, 

 against Coryneum spores. Iron and copper solutions must not be used indiscriminately, 

 but be tested on a few growths before applying to the whole of a tree or trees. Trees 

 liable to gum disease may be sprayed while dormant with this solution : caustic soda 

 4 ounces ; pearlash (carbonate of potash), 4 ounces. Dissolve, and dilute to 6 gallons 

 with hot water. If the trees have been infested with aphides, red spider, thrips, or 

 scale, add soft soap, 1 pound to the solution. Apply hot; 120 is quite hot enough for 

 soft shoots, but ripe wood will bear the solution 20 hotter. The soda and potash wash 

 cleanses the bark and increases its elasticity. 



When a tree is badly infested with gum disease every particle of diseased wood 

 must be removed. Shoots should be shortened to sound parts below the infestation, 

 branches be cut back or out to give place to healthy growths, and diseased stems have 

 the Coryneum extracted. Every possible care must also be taken to prevent infestation. 



