100 THE AMERICAN APPLE ORCHARD 



otherwise would have been sold and sent out to carry 

 the insect to new orchards. Fumigation has also killed 

 millions of scales on infested trees and has prevented 

 their distribution among unsuspecting tree buyers. And 

 yet neither nursery inspection nor nursery stock fumi- 

 gation is perfect, and in spite of both the scale has con- 

 tinued to spread. 



Any tree buyer should take every possible precaution 

 against introducing the San Jose scale into his 

 grounds. He should see that the trees he buys are ac- 

 companied by a certificate of inspection, and he should 

 do all he can to learn that that certificate means 

 something. If possible, he should have his trees 

 fumigated. For while impnoper fumigation does 

 sometimes injure nursery stock, proper fumiga- 

 tion is very effective in killing acale. After both 

 these matters have been duly attended to the tree 

 buyer will do well to give his trees a thorough inspec- 

 tion on his own account. It is fundamentally necessary 

 of course that the fruit grower himself should know 

 the scale when he sees it. 



Yet, after all, the San Jose scale problem is not one 

 of inspection nor of fumigation, but of fighting- the in- 

 sect in the orchard. In this campaign it is best to cut 

 down and burn a good many old trees or those very 

 badly infested before discovery. The battle is hard 

 enough anywhere ; but in old, unpruned, high-topped 

 trees it is almost surely a losing fight. It is important 

 that young trees be headed low. The San Jose scale 

 has done more than all 'Other agencies combined to 

 popularize the low heading of fruit trees. 



On individual small trees the scale may be killed by 

 fumigating the entire plant with h\'drocyanic acid gas, 



