SUMMARY OF IXSECT COXDITIOXS DURING 1921. 



45 



first discovered by H. B. Weiss and E. L. Dickerson, about the middle 

 of August. 1916. m a nursery near Riverton. An interesting coin- 

 cidence is that this insect was first discovered about a quarter of a 

 mile from the place where the San Jose scale was first discovered in 

 the eastern part of the United States. 



The rate of increase has been remarkable. In 1916 about a dozen 

 beetles were found, while in 1919, in the same locality, one person 

 could collect by hand from 15.000 to 20.000 beetles in a day. and as 

 many as 250 larvae to the square yard. 





V 



X- 



V 



o* / 



>rf TA ?f 



- — . 



/ ^0aJSTLETONy 



o 



-.row/ - - ' ) 



^ V- X-- ' . BURL^NGTOI 



V\ .Otv / - '/r.-L c inr ( . '.. \ ~ \ 



Fig. 25. — Geographical distribution of the Japanese beetle in the United States since its 



discovery in 1916. 



The area infested in New Jersey is mainly a market-garden and 

 fruit-growing section, with Philadelphia as its chief market, while in 

 Pennsylvania it is largely a residential section with much less land 

 given up to farming. A considerable number of greenhouses and 

 nurseries fall within this infested area, some handling only cut 

 flowers, while others have a varied line of plants, bulbs, and outdoor- 

 grown stock. 



The area infested in 1916 covered approximately 0.9 square mile 

 south of Riverton, N. J. ; in 1917 this area had increased to 2.7 square 

 miles; in 1918, to 6.8 square miles; in 1919 it had reached the Dela- 



