664 THE MONTHLY BULLETIN. 



only prevent the unnecessary spread to uninfected soils and prevent 

 losses to planters from planting and caring for visibly infected trees. 

 From abundant experience it has been determined that an allowance 

 of one per cent of stock visibly infected with crown gall in an 

 imported shipment, is fully ten times as much as reliable nursery- 

 men need as a margin against unavoidable oversights. On the other 

 hand, it is of advantage to the fruit interests of this State to have the 

 allowance placed as low as possible. Shippers will be less likely to 

 make their selections from grossly infected lots of stock, the proportion 

 of incipiently diseased stock will be, on the whole, greatly reduced, and 

 incidentally Arizona customers will not be forced to pay the transporta- 

 tion charges on an unreasonable proportion of diseased trees. 



In consideration of the facts above presented, with the desire to meet 

 the needs of both the shippers and importers, the writer has, under 

 date of January 31, 1913, issued the accompanying instructions to 

 Arizona crop pest inspectors. 



A. W. Morrill, State Entomologist. 



INSPECTION ORDER NO. 3. 



Crown Gall. 



Since "crown gall" is of common occurrence in all parts of the 

 country, occurring in practically all nurseries, particularly in the west, 

 since this disease is already prevalent in Arizona, and since it is impos- 

 sible by means of inspection to entirely prevent further introduction of 

 the infection, one per cent is hereby established as the maximum degree 

 of infection to be passed by Arizona crop pest inspectors. If more 

 than one tree in a hundred of a kind (apple or peach, for instance), is 

 plainly infected with crown gall, all of that kind will be rejected and 

 not released. Such other kinds of trees or plants as may be in the 

 same shipment, but do not show crown gall infection to exceed one per 

 cent, will be released. Every tree or plant showing crown gall disease 

 will be discarded. If the shipment, or any kind of plant or tree com- 

 prising the shipment, shows infection in excess of one per cent, samples, 

 selected in the presence of the consignee or some other person, if pos- 

 sible, will be submitted to the office of the State Entomologist, and the 

 remainder of the diseased stock held for advices from the owner. as to 

 option specified in section 15, crop pest law of 1912. If one per cent 

 or less of the shipment, or any kind of plant or tree contained therein, 

 is found to show crown gall infection, all diseased and suspected stock 

 must be burned, as a condition of the issuance of the release for the 

 balance of the stock. 



For the protection of the consignee, trees that are "strongly sus- 

 pected" of crown gall infection will be discarded at the time of inspec- 

 tion, but in figuring the percentage of trees infected when the amount 

 is close to one per cent, none but well developed and characteristic 

 infections will be counted. Roughened draft unions should not be 

 counted as crown gall infections unless the development of "callus" at 

 that point is excessive as illustrated in Bulletin 186 (Plate VIII, fig. 2) 

 of the Bureau of Plant Industry, United States Department of Agri- 

 culture. Whenever a shipment of any kind of tree, vine or plant in a 

 shipment shows well defined crown gall infection in excess of one per 



