BY PLANTS AND VEGETABLES 461 



foreign scale insects 1 all of them injurious to vegetation and 

 some of them, such as the Mulberry Scale (Aulacaspis pen- 

 tagona) and the Lantana Bug (Orthezia insignis] which 

 is steadily extending into fresh districts, containing great 

 possibilities of damage and destruction. 



It must not be supposed, however, that trees confine their 

 imports to Scale Insects. The name of one of the most 

 widespread and persistent pests of our orchards the Ameri- 

 can Blights-indicates its origin, though it is hard to believe 

 that in a century and a half an alien could have so thoroughly 

 become part and parcel of our fauna. The American Blight 

 or Woolly Apple Aphis (Eriosoma lanigera] a species of 

 plant-bug or greenfly, was unknown in England till 1787 

 when it was traced by Banks to a nursery in Sloane Street, 

 London. Several facts, apart from the tradition of its origin, 

 suggest that America is the true home of the Woolly Aphis; 

 but, much against his will, man has established it in practi- 

 cally all the apple-growing countries of the world. 



America has also been generous in her dispersal of a 

 closely related plant-bug the Grape Phylloxera (Phyl- 

 loxera vastatrix). Introduced into France before 1863, 

 upon rooted vines from America, the Grape Phylloxera 

 gained so secure a footing that by 1884 it had destroyed 

 about two and a half million acres, more than a third of all 

 the vineyards of France, and to-day there is scarcely a vine- 

 growing country of any importance where the Grape Bug 

 has not appeared, to the dread and loss of vine-growers. It 

 is a curious comment on the thoroughness of the distribution 

 of animals through, commerce, that this American Vine Bug, 

 which under natural conditions never reached California from 



1 Prof. R. Newstead in 1901 gave the following list of Scale Insects 

 imported on living plants into Britain during the twelve years which closed 

 the past century. (For the sake of uniformity I have substituted the modern 

 synonyms and have added the popular names.) Aspidiotus alienus, discovered 

 in 1889; the Mulberry Scale, Aulacaspis pentagona, imported in 1898; the 

 Orange Mussel Scale, Lepidosaphes beckii, common on oranges and lemons and 

 found also on imported plants; the Coffee Scale, Ischnaspis longirostris, now 

 a frequent greenhouse pest ; Gymnaspis cechmece, well established and in- 

 creasing; Fiorinia fiorinice and-/'! kewensis, on palms; the Screwpine Scale, 

 Pinnaspis pandani, a very destructive palm pest; the Lantana Bug, Orthezia 

 insignis, steadily extending its area; and the Egyptian Cushion Scale, Icerya 

 aegyptiacum, which was discovered and destroyed with its host plants on 

 importation. 



