374 REPORT OF STATE BOARD OF HORTICULTURE. 



carrying the insect to a distance. The importance of this means of distrib- 

 uting various insects has only been fully realized in this country in the last 

 few years, but the present instance and some other notable ones of like 

 nature have emphasized the great danger incurred not only in the indis- 

 criminate introduction of jjlants from foreign sources, but also in the carriage 

 of plants from one part of the country to another without competent inspec- 

 tion. The San Jose scale is also frequently carried about on fruit, as the 

 young very commonly crawl out upon the fruit, particularly with the pear, 

 and is thus shipped to remote points. It may be frequently thrown out on 

 parings and the young larva may gain access in this way to trees. This 

 method of transportation was strikingly illustrated at the meeting of the 

 Association of Economic Entomologists held in Brooklyn in 1894, when 

 Prof. J. B. Smith exhibited a number of California pears purchased from 

 the nearest fruit stand, all of which were badly infested with the scale, 

 showing many full-grown females, and, in some cases, young larvae crawling 

 about. Such fruit is sold on all trains and in practically all large towns in, 

 the United States. Prof. .J. W. Toumey states ( Bulletin 14, Arizona 

 Experiment Station, p. 35 ) that he has jDurchased California pears and 

 apples in the fruit stalls of Phoenix and Tucson infested with both female 

 and male scales, and Professor Smith reports a like experience in the 

 markets of Philadelphia, Newark, New York, and Brooklyn. The danger 

 of infestation from parings and rejected fruit will, therefore, be easily 

 understood. 



The spread of the insect from orchard to orchard and from tree to tree 

 must also be brought about through the agency of means other than those 

 under the control of the insect itself. The female is wingless, and after 

 once becoming fixed can not move. The young lice, as before stated, are 

 active, crawl rapidly, and may reach other trees, but this is rare unless the 

 limbs interlace, since we have shown by breeding-cage experiments that the 

 larvae normally crawl but a few inches. Such spread, however, is compara- 

 tively insignificant except in the case of nursery stock, which is grown 

 close together. It is possible that strong winds may carry the young bodily 

 from one tree to another, or, they may be floated on water to distant points, 

 particularly in irrigated districts, but the principal method of the spread of 

 these young lice is by means of other insects, and by birds. The active 

 young lice soon crawl upon any small winged insect, particularly if the 

 latter be of a dark color, and may thus be carried considerable distances. 

 They are frequently found crawling upon ants, which are great travelers. 

 It is extremely probable that they also crawl upon the feet of birds, and 

 may be transported by these carriers for many miles. 



Some interesting observations have been made by Mr. Schwarz upon the 

 transporting of these scale larvae by other insects. A little black ladybird, 

 Pentilia mhdla, which was very active in devouring scale larvas, was 

 unfortunately equally efficient in transporting many of these young lice to 

 other parts of the tree or to other trees ; in fact, it was difficult to find a 

 single beetle which did not carry on its back at least one larva of the San 

 Jose scale, and sometimes three or four were found upon a single wing-cover 

 of a beetle. The small black ant, Monomorium minutum. was particularly 



