PEAR DISEASES 



1G47 



tions in the young twigs, and even tlie 

 bodies. Sapsuckers, or woodpeckers may 

 also spread the hlight. The use of prun- 

 ing tools not disinfected also spreads 

 it. The blight may also enter small 

 growth cracks in the twigs, limbs, bodies 

 and roots, and through crown galls. 



10. Weather conditions favor the 

 spread of blight, as well as favoring in- 

 fection. Dry weather tends to prevent 

 not only the spread of infection from tr°e 

 to tree, but also the spread of the disease 

 in the tree itself. It is as easy to under- 

 stand this as it is to understand that dry 

 weather prevents growth and germina- 

 tion of seeds and plants. 



11. Thunder, lightning and other atmo- 

 spheric disturbances have no influence 

 whatever on the disease known as pear 

 blight. The precipitation which accom- 

 panies them is the only factor besides 

 warmth. 



12. The only way to control blight is 

 to remove all cases of hold-over before the 

 blossoming period begins. Hold-overs re- 

 moved during the blossoming period do 

 not insure that some infection has not 

 taken place from them. To remove hold- 

 overs, or rather to find them, on the 

 rough bodies use a gouge or some other 

 instrument with which to expose the tis- 

 sues beneath. A water-soaked, reddish 

 condition of the soft bark indicates in- 

 fection, which should be antiseptically re- 

 moved. 



13. The antiseptic to be used should be 

 bichloride of mercury, or corrosive sub- 

 limate. Use no other. This disinfectant 

 should be used at a strength of one to 

 1,000, or perhaps stronger, but never 

 weaker. The use of the various substi- 

 tutes is a senseless practice, as there is 

 nothing cheaper or more effective as a 

 disinfactant than bichloride of mercury. 

 It is a deadly poison and must be kept 

 away from children, and the containers 

 should be plainly labeled, so that unsus- 

 pecting persons may not be poisoned. 

 Never put in a metallic container; always 

 use glass or wooden vessels. 



14. Th^re are no remedies for pear 

 blight, and all so-called patent washes or 

 other "remedies" should be avoided. Any- 



one who claims to have a cure for pear 

 hlight is a "fake," and should be treated 

 accordingly. Those having "remedies" 

 for sale nave no standing whatever; if 

 they had they would not oppose every 

 scientific fact known. 



15. Summer cutting of blight should 

 always be done, but the work, to be ef- 

 fective, must be done carefully. Always 

 be sure to get below or above the point of 

 infection. If infection is found in fruit 

 spurs or water sprouts never break them 

 off unless you know how far the infection 

 has gone. There is no further danger in 

 the dead spur, but rather in the infection 

 which has advanced beyond it. Breaking 

 off the spur and then applying the disin- 

 fectant is not eradicating the blight. 

 Never leave an infection imtil you know 

 that there is no further danger from it. 

 Remember that there is no such thing as 

 "pretty good work;" the work is either 

 good or bad. 



16. In order to render the fighting of 

 pear blight more easy, trees should be 

 pruned in the vase or open-head form. 

 Never grow a tree with a main leader or 

 center. Keep all water-sprouts and fruit 

 spurs off the body and main limbs of the 

 tree. Let no water-sprouts come up from 

 the crown of the tree or the root system. 

 Cut out all crown galls. 



17. When blight is prevalent or when 

 seasons conducive to blight occur, ex- 

 treme caution should be used in the mat- 

 ter of using stable manure, commercial 

 fertilizer or applying too much water. Ir- 

 rigation practice should be studied care- 

 fully, not only in connection with blight 

 control, but with benefits or injuries 

 which may result to the soil. 



18. The only way to keep blight un- 

 der control is to increase the inspection 

 and make it rigid. If a grower is caught 

 experimenting, or not following out the 

 directions for eradicating blight accord- 

 ing to the letter of the law, force him by 

 law to do what the inspector has ordered. 

 Besides the regular corps of inspectors 

 there should be volunteer inspectors who 

 will look after their own interests by in- 

 vestigating the condition of neighboring 

 orchards. Their appointment may be 



