INSECTS IN RELATION TO MAN 397 



Introduction and Spread of Injurious Insects. Many of 



our worst insect pests were brought accidentally from Europe, 

 notably the Hessian fly, wheat midge, codling moth (prob- 

 ably), gypsy moth, cabbage butterfly, cabbage aphis, clover 

 leaf beetle, clover root borer, asparagus beetle, imported cur- 

 rant worm and many cutworms ; though few American species 

 have obtained a foothold in Europe, one of the few being the 

 dreaded Phylloxera, which appeared in France in 1863. 



The gypsy moth, liberated in Massachusetts in 1868, cost 

 the state over one million dollars in appropriations (1890- 

 1899) and is not yet under control. The San Jose scale, a 

 native of North China according to Marlatt, was introduced 

 into the San Jose valley, California, about 1870, probably upon 

 the flowering Chinese peach, became seriously destructive there 

 in 1873, was carried across the continent to New Jersey in 

 1886 or 1887 on plum stock, and thence distributed directly to 

 several other states, upon nursery stock. At present the San 

 Jose scale is a permanent menace to horticulture throughout 

 the United States and is being checked or subdued only by the 

 vigorous and continuous work of official entomologists, acting 

 under special legislation. This pernicious insect occurs also 

 in Japan, Hawaii, Australia and Chile, in these places probably 

 as a recent introduction. 



The Mexican cotton boll weevil (Anthonomus grandis) 

 crossed the Rio Grande river and appeared in Brownsville, 

 Texas, about 1892, since when it has spread over eastern Texas 

 and even into western Louisiana. Advancing as it does at 

 the rate of fifty miles a year, the insect would require but fif- 

 teen or eighteen years to cover the entire cotton belt. The 

 beetle hibernates and lays its eggs in the cotton bolls; these 

 are injured both by the larva feeding within and by the beetles, 

 whose feeding-punctures destroy the bolls and cause them to 

 drop. If unchecked, this pest would destroy fully one half the 

 cotton crop, entailing an annual loss of $250,000,000. As it 

 is, the universal adoption of the cultural methods recommended 

 by the Bureau of Entomology promises to reduce the damage 

 to a point at which cotton can still be grown at a fair profit. 



