82 Bulletin N t o. 34. 



there is no reason why the peach should not be a very profitable 

 crop in southern Arizona, where a failure to set fruit is so rare. 



A. J, McClatchie, 

 Department of Agriculture ani Horticulture. 



THE DANGER OE INTRODUCING INSECTS ON TREES.. 

 No. 7, January i, 



At this time of the year it is appropriate to call the attention 

 of those who may be importing; young trees to the danger of 

 introducing with them various insects. Inasmuch as there is at 

 present no system of horticultural quarantine in Arizona, it is 

 necessary for each individual importer to see that his own trees 

 are clean; and it is to his interest to pursuadehis neighbors, so far 

 as they are importers of trees, to be similarly careful. 



There is a common belief in the Salt River Valley that in- 

 fested trees may safely be planted, because the scales or other 

 pests which may be upon them will not survive. There is plenty 

 of testimony proving that the black scale of California has repeat- 

 edly been brought to Phoenix on young orange trees, and the 

 trees set out infested; yet at the present time no trace of black 

 scale can be detected in the orchards. This points to what is in- 

 deed the fact, that scales and other insects brought from relatively 

 moist regions to Arizona have a hard time to exist and propagate. 

 Especially when they come on young trees, they are exposed to 

 the direct rays of the sun, and are liable to perish before the plant 

 affords enough shade to protect them. 



Admitting all this, however, there is plenty of reason for the 

 most scrupulous care. Under certain conditions, scales which 

 normally inhabit moist and relatively cool regions, will flourish 

 even in the Salt River Valley. The San Jose scale is a case in 

 point. This has been brought in, undoubtedly, on young trees, 

 and has survived for many years in Phoenix. In an orchard at 

 Glendale, where the pear trees are fairly large, and are protected 

 by shade trees from the full force of the sun, this scale is rampant, 

 covering the bark of the trees, and overrunning the fruit and 

 leaves, rendering the product quite worthless. 



