18 CROP PEST COMMISSION OF 



Quite conclusive evidence that the San Jose scale is thus 

 disseminated upon teams and tools was found during the past 

 season in a block of nursery stock about 200 yards in length and 

 about 50 yards in width, the rows running lengthwise of the 

 block. This entire block had been budded in the spring of 1904 

 with buds shipped from a distance. Upon examination of this 

 block of nursery stock in October, 1905, an occasional tree was 

 found which was practically incrusted with the San Jose scale, 

 the infestation being much the heaviest upon the lower part of 

 the trunk near the point where the bud had been inserted. Evi- 

 dently these trees became infested as the result of an occa- 

 sional bud of the original lot bearing one or more scales. That 

 the number of scales on the buds was very small was evidenced 

 by the small number of trees infested in this manner. In sev- 

 eral other portions of the same block many trees were found 

 infested with but a few scales, and these scales were in all cases 

 upon the side limbs and upon the tops, never upon the lower 

 part of the trunks. The distribution of the scale through this 

 block in such a manner (See Figure 9) cannot be explained ex- 

 cept by the supposition that the minute lice were carried from the 

 heavily-infested trees to the others upon the horses or harness 

 used in cultivating the trees. 



Mr. R. I. Smith, State Entomologist of Georgia, cites a case 

 in which peach pickers evidently carried the scale from one orch- 

 ard to another. In the forenoon of a certain day the "gang" of 

 pickers worked in an infested orchard and in the afternoon of the 

 same day worked, with the same baskets, in an uninfested orchard 

 some distance away. A few months later infestation by the scale 

 was found in the latter orchard and was most in evidence near the 

 point where the pickers had first entered when coming from the 

 infested one. 



It seems likely that winds may blow the young lice from one 

 tree to another and it seems to the writer not at all improbable 

 that whirlwinds, such as are often prevalent during the dry sum- 

 mer months, may take up hundreds of these lice from an infested 

 tree, only to let them descend broadcast over a considerable area 

 when the force of the whirlwind is expended. This, while .1 

 theory only, would account for many peculiar cases of local dis- 

 tribution which seem inexplicable in any other way. 



