384 BIOLOGICAL CONTROL 



required, and in this way it has been widely disseminated wherever 

 it did not previously occur. It has now become to be relied upon 

 in preference to any other natural enemies, since it often attains 

 90 per cent, or more parasitism of the fruit moth larvae. Its chief 

 value is as an accessory, since artificial control usually has to be 

 maintained also in the chief centres of infestation. The promise 

 shown by Macrocentrus has led to its introduction into other 

 countries where the fruit moth is prevalent, notably into Italy and 

 Japan. 



The Japanese beetle was introduced in shipments of Japanese 

 iris in 1911, and in the course of ten years it has invaded about 

 14,000 square miles of territory, including the entire state of New 

 Jersey and portions of Connecticut, New York, Pennsylvania and 

 Delaware (L. B. Smith, 1928). At the present time, however, it 

 covers a still wider area and has reached the Middle West, while 

 its entry into Canada is being closely watched. The heaviest 

 infestations still occur in New Jersey and adjacent territory. Its 

 chief depredations are caused by the adult beetle attacking the 

 fruit and foliage of apples and peaches, but it also affects a great 

 variety of other fruits, together with vegetable crops, shade trees, 

 etc., while the larvae, it may be added, are destructive to lawns 

 and pastures. In 1920 work on the insect enemies was commenced 

 in Japan, where parasites are important agents in controlling the 

 insect. The fact that at least five species of parasites participate 

 in reducing the abundance of the beetle in Japan led the United 

 States Bureau of Entomology to undertake the problem of building 

 up an ecological association of parasites similar to what obtains 

 in that country (King, 1928). In 1922 investigations were 

 extended to Korea, where the study of parasites of closely allied 

 beetles was commenced, and later the work embraced also 

 parasites of allied beetles found in China and India. Since this 

 expansion has taken place, parasites have been transmitted to 

 America from each of the countries mentioned. From among 

 about a dozen or more possible species, those established in the 

 United States up to 1927 included three Tachinids and two solitary 

 wasps of the genus Tiphia. Of the Tachinids, Centeter cinerea 

 parasitises the adult beetles, while Prosena siherita and Dexia 



