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ENCYCLOPEDIA OK PRACTICAL HORTICULTURE 



other non-resistant varieties liave 

 blighted as far as thi> Nelis and KiefCer 

 stocks, the infections have usually 

 stopped at the graft union. Every pear 

 grower on the Coast who has had ex- 

 perience with blight knows that Winter 

 Nelis and Kieffer, the latter being very 

 rarely grown, seldom blight seriously, 

 although they may be surrounded by a 

 great deal of infection. Of course, we 

 do know, on the other hand, that they are 

 not immune even on the Coast. I could 

 offer as a suggestion that Kieffer stocks 

 might well be set out and afterwards 

 top-grafted to any of the commercial va- 

 rieties of pears. This will, at least, pro- 

 vide resistant bodies and roots which will 

 eliminate the danger of loss by body and 

 root infection. I wish to urge that the 

 finding of a variety of pear entirely im- 

 mune to pear blight will alone solve the 

 pear-blight i)rohlem for this species of 

 pome fruit. The same will be true of 

 any other of the pome fruits. As soon 

 as an immune is found the possibilities 

 of plant breeding will, no doubt, evolve 

 commercial varieties equal to those that 

 we have now, and, at the same time, they 

 will be immune from disease. This is 

 looking far into the future, but it will 

 be done as it has been done with other 

 plants. 



Ertidiciition of niiirli) 

 Some remarkable cases of eradication 

 have been attempted and successfully 

 accomplished in California and Oregon 

 orchards, notably in the vicinity of Vaca- 

 ville, California, and in the upper Rogue 

 River valley in Oregon. In some cases 

 where perhaps 50 per cent of the trees 

 were infected on the bodies and In the 

 roots, but still had sufficient living bark 

 and a few roots left, the diseased por- 

 tions were completely cut out, even to 

 the removal of all of the roots on one 

 side of the tree and peeling fully three- 

 fourths of the bark from the body. I 

 have noted in some instances where fully 

 three dollars in labor was expended in 

 removing the blight from a single tree. 

 This, of course, is exceptional, but where 

 the value of the tree may be placed at 

 from ten to fifty dollars, depending upon 



its ability to bear heavy crops of fruit, 

 this would not seem to be an undue ex- 

 penditure in eradicating the blight and 

 saving the tree. Many of the trees so 

 treated have not lost their vigor and are 

 still bearing good crops of fruit. From 

 the standpoint of the pathologist, if the 

 pear blight is completely removed under 

 antise])tic methods from the body and 

 roots, the job is satisfactory. It remains, 

 therefore, with the grower to decide how 

 much labor he is going to undertake to 

 save the tree. Experience throughout 

 the East and South has been that where 

 much work of this sort has been at- 

 tempted on the bodies, numerous failures 

 have resulted, and the work rendered 

 worse than useless. There is also more 

 or less danger, in such cases, of the 

 blight in the sap wood. While the germ 

 almost wholly lives in the bark and cam- 

 • bium, it is also known that it may infect 

 the rich sap wood of the Bartlett, Howell 

 and other varieties of pears. This is also 

 true of the Spitzenburg apple. Occa- 

 sionally it has been noted that the germs 

 spread out in the vessels of the wood 

 and live on the starch and sugar stored 

 there. It is, therefore, desirable to let 

 all eradication work on the bodies dry 

 out thoroughly for perhaps a month or 

 so before painting over the wound with 

 white-lead paint. If any growth of dis- 

 ease takes place the ooze may be detected 

 by the discoloration appearing on the 

 paint. It is certain that a great deal of 

 blight eradication work may be done to 

 the best advantage in the early autumn, 

 for certainly better results may be ob- 

 tained before the fall rains begin. It is 

 also much easier to detect the blight 

 which has attacked the branches and 

 twigs during the summer, because at this 

 time the foliage generally shows where 

 the blight has been working. Besides, 

 trees that have the roots infected usually 

 begin to show a reddish discoloration in 

 the foliage. A bad body or limb infec- 

 tion will also have a tendency to cause 

 the same discoloration in the foliage 

 above the infected part. However, this 

 reddish discoloration of the foliage is by 

 no means a certain indication of blight 



