PEJAR. DISEIASES 



1631 



tion of this will generally result in the 

 finding of a case of hold-over blight in 

 the center and from which all trouble 

 may be traced. During the first year's 

 work those who are just learning how 

 to eradicate blight will probably miss a 

 good many cases; however, after prac- 

 tice they usually become keener and 

 rarely miss any. In fact, I have seen 

 men who from the very first were able 

 to do excellent work, but, like other jobs 

 which require careful work and a sharp 

 eye, relatively few men are capable of 

 making first-class inspectors. In many 

 of the large orchards where the question 

 of eflacient labor is serious and where all 

 sorts of tramp and other low-class labor 

 has been employed, absolute failures in 

 blight control have generally resulted. 

 As I have stated before, even the better 

 sort of laborer cannot be thoroughly 

 schooled in careful work of this kind 

 within the space of a day or two. In 

 every event, the best and most careful 

 men should be placed in charge of work 

 of this kind. It is a common mistake to 

 think that the matter of eradication and 

 control rests with the inspector alone. 

 An inspector must have the co-operation 

 of the entire district. I do not know of 

 any one who would ask an inspector to 

 assume the matter of cultivation, prun- 

 ing or any other of the regular orchard 

 practices; neither should an inspector be 

 asked to do the actual work of blight 

 eradication. The inspector is, in the first 

 place, an instructor, and in the second 

 place, the one to enforce the horticul- 

 tural laws, but he is no common hired 

 man. 



'No Spray Remedy 

 It must be understood from the very 

 beginning that there is no spray cure or 

 remedy for blight. It is a bacterial dis- 

 ease, and once the germ has gained en- 

 trance to the bark tissues and the cam- 

 bium layer, by no means whatever can 

 any external application in the way of 

 a spray be effective. There is but one 

 thing to do after infection has started, 

 and that is to remove by cutting out the 

 affected parts. In other words, the oper- 

 ation is purely surgical. In all of the 



cutting a strong disinfectant should be 

 used to wipe off the tools after cutting 

 into the blight as well as to wash off the 

 wounds made by the instruments; other- 

 wise, it is possible to introduce the germ 

 into the cut surface and to carry it from 

 tree to tree on the pruning tools. In the 

 majority of cases in dry weather infec- 

 tion would not result 'from the use of 

 pruning tools, even though they were not 

 disinfected, but it is never a wise plan 

 to take a chance. In the late summer 

 or early fall when the exuberant grow- 

 ing season is over, the chances for infec- 

 tion by the use of unclean tools are not 

 so great; however, it has been deter- 

 mined by numerous experiments that 

 blight punctured into the fresh bark in 

 the fall may remain semi-dormant 

 through the winter and may result in a 

 fine case of hold-over blight the follow- 

 ing spring. In working out blight as 

 much care should be used to prevent 

 accidental inoculation and infection as a 

 surgeon would use in performing a major 

 operation. 



Disinfection of Tools and Cnts 



For disinfecting the cut surfaces and 

 the instruments, the best thing to use 

 is a solution of corrosive sublimate, or 

 bichloride of mercury, in water, one part 

 to one thousand. It is often advisable 

 to use the disinfectant a little stronger, 

 and there is no danger in using one to 

 five hundred. Tablets may be obtained 

 from any drug store, and the number to 

 be used to produce any strength of solu- 

 tion is usually indicated upon the bottle. 

 To be sure that no mistake is made, ask 

 the druggist how many tablets to use to 

 produce a solution of desired strength. 

 When possible, use rain water, as the 

 slightly alkaline waters in dry countries 

 tend to precipitate the poisonous mercu- 

 rial compound. Also use a glass or non- 

 metallic container, as a tin can or other 

 metal container will react on the disin- 

 fectant and remove the poisonous prin- 

 ciple. Corrosive sublimate kills the pear- 

 blight germ in solutions in water when 

 it is diluted to one part to 10,000; there- 

 fore, the above formulae are sufficiently 

 strong and well within the limits. While 



