SUMMARY OF I2?"SECT CONDITIONS DUEING 1921. 



45 



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

 of August, 1916, in 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 larvse to the square yard. 



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 191T this area had increased to 2.7 square 

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



