176 Bulletin 176. 



to suggest that " this was nndoubtedlj' the native food-plant 

 of tlie insect before the importation of peach-trees." In 1896, 

 '' G. E. M." of Virginia recorded that his Japan plum-trees on 

 Mjrobolan or Marianna plum stocks were as badly infested as his 

 peach trees, whereas when budded on Chickasaw or other native 

 varieties, thej were entirely exempt. This evidence, in connection 

 with the fact that we have found no record of the peach-tree borer 

 having been found in our native wild plums, would indicate that the 

 wild cherry is more likely to have been its original food-plant than 

 the wild plum ; perhaps it originally fed upon both these plants. 

 Whatever may have been its original food-plant, it has evidently 

 almost entirely forsaken it for the peach. 



How IT Spreads. 



The " borer " or caterpillar probably never leaves the tree upon 

 which it is born fi'om the egg laid on the bark, and the insect spends 

 nearly eleven months of its yearly life-cycle on or in the tree. It 

 thus can be easily transported for long distances on infested trees, 

 and this is doubtless the way in which it usually reaches new localities. 

 In the spring and fall^ when trees are usually transported, many of 

 the " borers " are quite small and easily escape casual observation. 

 As large peach trees are rarely moved, the growers of nursery stock 

 are most responsible for the introduction of the insect into new 

 localities. As early as 1806, Peters had "discovered the worms in 

 or near the roots of the smallest stocks taken from the nursery." 

 In 1824, Thomas states that he believed the pest was introduced 

 into the neighborhood of Baltimore on nursery stock from JSTorthern 

 and Eastern nurseries, for many of the trees received from there 

 were infested. It has been found on nursery stock sent into Cali- 

 fornia from Southern nurseries, and it doubtless reached New 

 Mexico and Colorado in a similar manner. Mr. Lowe (1897), states 

 that " it is a too common occurrence in our own State (N. Y.), to 

 find many young peach trees in the packing shed, waiting to be 

 shipped, which are infested by borers. Within the past few months 

 Imndred of such trees have been found which were about to be 

 packed and shipped to some distant State." It is doubtful if there 

 is a peach nursery to-day east of the Bocky mountains that is not 



