513 



WATER CORE. Easily known by the watery or waxy appear- 

 ance of either the whole or part of an apple. The apple is quite 

 sound to outward appearance. More prevalent in moist seasons, 

 especially in early sorts. Winter varieties are comparatively free 

 from it. Stone Pippin and Five Crown Pippin are somewhat 

 subject to it. 



PEAR BLIGHT, or FIRE BLIGHT (see Twig Blight, p. 511). A 

 bacterial disease which attacks apples, pears, quinces, and other 

 trees. It works in the tissues between the bark and the growing 

 wood, only during the growing season. 



Some varieties of pears, like the Duchess and Kieffer's Hybrid, 

 resist the disease better than others, such as Bartlett and Clapp's 

 Favourite. 



The blight microbe is greatly influenced by climatic conditions ; 

 warm and moist weather, with frequent showers, favouring it. 

 These conditions are prevalent in the month or two following 

 blossoming time. Dry, cool, and sunny weather hinders it, while 

 very dry weather checks it ; and it remains dormant during the 

 winter. The line of demarkation between healthy and diseased 

 wood is then often quite marked. 



In the spring, when sap pressure runs through the tree, the 

 blighted parts are recognised by the moist and fresh appearance of 

 the bark, as contrasted with the old and dry bark of the previous 

 summer. The gum exudes from various points, and runs down the 

 tree in long lines, when bees and other insects which are attracted 

 by it carry the microbes to the blossoms, where they gain an easy 

 entrance into the healthy tissues under the bark. These blossoms 

 soon wither and die. Tender twigs are often inoculated by nibbling 

 insects, and show signs of the blight. 



Some observers contend that because the microbe flourishes 

 best in tender tissues, anything which tends to luxuriant growth of 

 the tree, such as pruning, manuring, cultivating, are to be depre- 

 cated ; and they advise leaving it to the trees to fight their own 

 battles. If this be the correct treatment, it appears to me that it is 

 time, labour, and money wasted to grow apples, pears, and quinces in 

 those places where the disease is prevalent, as stunted, hungry trees 

 are even less profitable than blighted ones. 



Little is known as yet concerning the best means of combating 

 this bacterial disease ; and the subject is worth experimenting with. 

 Until the results of well planned out experiments have proved 

 the contrary, I would recommend deep and good cultivation, and 

 fertilising with gypsum, potassic and phosphatic fertilisers, efficient 

 deep drainage, carefully cutting off all diseased branches and twigs, 

 and burning them in the winter, care being taken to cut into 

 healthy wood and to disinfect the secretion on the knife after going 

 over a diseased tree. Lastly and I believe that much good can 

 then be done in checking the spread of the fire blight spraying the 

 diseased trees at frequent intervals with an antiseptic solution in 



