PEAR DISEASES 



1637 



infection, as tliere are many other causes 

 wliich would produce a like appearance 

 in the foliage. Root rot, borers, gophers 

 or even a girdle caused by any means 

 whatever, will produce practically the 

 same discoloration. In irrigated orchards 

 where the water has been cut off too 

 early in the summer, there is always a 

 tendency toward foliage discoloration. 

 The foliage test, however, is a sure one 

 that something is wrong with the tree, 

 and such a tree should never be passed 

 by without making a very critical exami- 

 nation. Careless inspection and careless 

 eradication are really worse than no 

 work at all. for on the one hand enough 

 work may be done to deceive, while on 

 the other hand the chance for infection 

 and subsequent spread of the disease 

 remains. 



Popular Remedies 

 Spraying, as a rule, is of little use in 

 controlling the blight. In the blooming 

 season new blossoms are opening every 

 hour of the day and new shoots are push- 

 ing forth, all of which are subject to 

 infection through insect agencies. From 

 the standpoint, therefore, of attacking 

 the pear-blight problem by spraying, 

 there is nothing to be done so far as the 

 blossoms and young shoots are con- 

 cerned. On the other hand, we have been 

 able to cover up some mild cases by 

 whitewash, applied thickly, so that they 

 were unable, temporarily, to be a source 

 of infection during the blossoming sea- 

 son. Whitewashing or spraying in the 

 winter time may be of some slight as- 

 sistance in the matter, but it is not 

 recommended. A strong lime-sulphur 

 wash applied to the bodies just before 

 the blossoms open will have a tendency 

 to keep insects away from any infection 

 which would ooze. It must be under- 

 stood, however, that all pear blight infec- 

 tion should be carefully removed, and 

 in no case should there be any attempt 

 to cover up any known case of hold-over 

 blight. The only reason for advocating 

 the strong lime-sulphur wash is that, 

 should a case be missed by accident, the 

 use of the wash may prevent the infec- 

 tion from getting away. Just as soon 



as it is discovered, whether the wash 

 has been applied or not, it should be re- 

 moved. I wish to emphasize that any 

 attempt to spray or wash may be consid- 

 ered only a temporary makeshift. If 

 there is a case of hold-over that has been 

 covered by spray or wash, it must be 

 eventually removed, and especially so if 

 it is in the body of the tree. The wash 

 in no way controls the spread of the 

 blight in the soft bark beneath; its only 

 office is to prevent, if possible, the spread 

 of blight to other trees, by preventing 

 insects from coming into contact with 

 the bacterial ooze. 



There are on the market a number of 

 so-called remedies for pear blight. All 

 of the concerns selling these remedies 

 have no standing whatever, and their lit- 

 erature, which is sent broadcast over the 

 country, may well be promptly thrown 

 in the fire. A favorite remedy is a mix- 

 ture of potassium cyanide and sulphur 

 placed about the roots of the tree. Still 

 others consist of such insolubles as char- 

 coal, calomel, sulphur, bone black and 

 other substances put into holes bored 

 into the bodies of the trees. In every 

 community trees may be found that have 

 been treated in this way, and invariably 

 the material put into the holes has 

 neither changed its chemical makeup nor 

 has it diminished in quantity by absorp- 

 tion. 



A common remedy is the use of table 

 salt, or even some alkali. The use of 

 table salt Is merely to inhibit the growth 

 of the tree by preventing the normal tak- 

 ing up of water by the root system. A 

 tree grown in a very saline soil cannot 

 take up water enough to make a strong 

 growth, hence it does not blight badly; 

 perhaps not at all. There should be no 

 desire on the part of an orchardist to 

 injure his soil, and consequently his 

 trees, by adding to the soil any chemical 

 or salt known to have a poisonous action, 

 or, at least, an inhibitive effect. Do not 

 take the word of everyone or anyone who 

 has something to sell. Before buying 

 any cure or remedy, consult some one 

 who can be trusted and who has nothing 

 for sale. 



