558 THE MONTHLY BULLETIN. 



FISKE AND THE GYPSY MOTH, 



By Harry S. Smith^ Superintendent State Insectary, Sacramento, Cal. 



The Federal Bureau of Entomology has recently issued a circular, 

 Mo. 164, entitled "The Gypsy Moth" as a Forest Insect, AVith Sug- 

 gestions as to Its Control." This article hy W. F. Fiske, the foremost 

 authority on natural control of insects, will cause all lovers of trees, 

 especially those in New England, to breathe a bit easier. The gypsy 

 moth is no longer the dreaded pest of 1896 to 1900. While it is still 

 a vital factor in American forestry, wholesale devastation, not only 

 of all forest trees, but of fruit and shade trees and even gardens and 

 fields, is a condition which no longer prevails. The situation with 

 regard to this insect has become greatly improved within recent years. 



This improvement of conditions is said to be due to four main causes : 

 (1) The perfection and standardization of the methods of artificial 

 repression; (2) the death of a large proportion of the more susceptible 

 trQ.es or their removal from the infested woodlands; (3) the importa- 

 tion of parasitic and predatory insect enemies; and (4) the develop- 

 ment of the ' " wilt ' ' disease. 



California parasite enthusiasts have watched with considerable in- 

 terest the attempt to introduce the natural enemies of the gypsy 

 moth into New England. They will then be much interested in what 

 Mr. Fiske has to say with regard to the progress of this work. He 

 writes as follows : 



"There are about thirty species of insect enemies of the gypsy 

 moth which appear to be of importance in checking its increase in 

 Europe and Japan. All of the promising species have been imported 

 and colonized under more or less satisfactory conditions in America. 

 Not all have successfully accommodated themselves to their new 

 environment. About one third of the total appear to have done so and 

 to be steadily increasing in efficiency in accordance with their powers 

 of multiplication and dispersion. 



"It was hoped that more of them would acclimatize themselves; it 

 was feared that the number might be less. On the whole, the results 

 are decidedly satisfying, and the State of Massachusetts and the 

 United States Department of Agriculture have no cause to regret 

 having undertaken the unexpectedly formidable task of parasite im- 

 portation. Within a territory centering a little to the northward of 

 Boston, it may be conservatively stated that fully fifty per cent of the 

 eggs, caterpillars, or pupse of the gypsy moth, in the aggregate, were 

 destroyed by imported parasites in 1912." 



Owing to the great expense attached to the use of artificial means 

 of control, such as spraying, these methods are available only on shade 

 trees and in parks. In the infested New England forests the bacterial 

 or "wilt" disease and the insect enemies constitute the factors upon 

 which the authorities mainly rely for repression. Of these Mr. Fiske 

 states that — "More than to the parasites, more than to the perfection 

 of the methods of artificial suppression, the amelioration in conditions 

 is due to the 'wilt' disease." This malady is of bacterial origin and 

 is apparently similar to the fiacherie of the silkworm. It first appeared 

 in New England in 1903 or 1904. By 1911 it reached its climax and 



