100 



been prevented by Federal quarantine. The several 

 states themselves have passed regulatory measures to 

 prf vent the further spread of canker within the states 

 anrl from any one of them to any other of them. 



The use of fungicides and disinfectants indicates that 

 there is little to be hoped for in their use for protection 

 against citrus canker. Field tests have been made with 

 Bordeaux mixture, ammoniacal copper carbonate; sol- 

 uble sulfur, Bordeaux to which bichloride of mercury, 

 12 tablets to three gallons, had been added, Bordeaux 

 containing formaldehyde, 1-100, and Pyrox, Even 

 when all visible signs of the disease are removed from 

 the trees prior to the application of the fungicides their 

 nsfj does not prevent the reappearence of the disease on 

 these trees. 



Tlie only method known of checking citrus canker is 

 the complete destruction of all infected trees. Eradica- 

 tion by this procedure seems possible, but only when the 

 work has been thoroughly done, with the observance of 

 the strictest sanitary precautions. 



The early efforts toward the eradication of citrus 

 canker were confined to the removal of diseased parts 

 in case the trees were only slightly diseased. When 

 they were badly diseased the trees were severely pruned 

 even though this necessitated the removal of all or 

 nearly all of the branches. Trees thus treated were 

 then sprayed thoroughly with Bordeaux mixture. After 

 a few months trial it was found that the trees were 

 still diseased. Further than this, the adjacent trees 

 had become diseased, although they were apparently 

 healthy when the pruning was done. As a result of 

 this it was decided that only the complete destruction 

 of affected trees as they stand in groves or nurseries 

 would be effective. The eradication campaign with 

 its concerted, heroic efTort to stamp out citrus canker 

 from the (nilf States is the outgrowth of this decision. 



