BUKEAU OF ENTOMOLOGY. 307 



numbers al(>»ii^ the entire shore of the hike in Xew York, Pennsyl- 

 vania, and Ohio. In Michigan it was also found in a few townships 

 along" the lake just south of Detroit. 



How the corn borer became established in this important territory 

 is not definitely known, but there is circumstantial evidence that the 

 moths may have been blown by the wind across Lake Erie from the 

 intensely infested area immediately south of London and St. Thomas, 

 in Ontario, Canada. The records of the Weather Bureau show that 

 tlie prevailing winds blew rather constantly from that region during 

 the flight season of the moths in 1921. In order to study the insect 

 in this new area, a field laboratory has been established at Sandusky, 

 Ohio, for the purpose of learning all the important facts which 

 may in any way be used to combat the pest in this region. Stations 

 as centers of scouting and certification of crops have been established 

 at Cleveland and Toledo. Ohio. 



While injury to crops l)y the corn borer in the newly infested 

 territory in Ohio and Michigan is not likely to become very evident 

 for some time, perhaps not for several years, nevertheless the close 

 proximity of this iiew infestation to the principal corn belt of the 

 country makes it practically certain that the pest will reach that 

 region by flight or otherwise within the next few years. 



The work of introducing the natural enemies of the corn borer 

 from Europe has made rapid strides during the year. Experts 

 located at Hyeres, southern France, have been almost constantly 

 collecting and shipping insect parasites of the corn borer to America, 

 where these have been assorted and reared, to be subsequently lib- 

 erated in large numbers in the heavily infested regions of New 

 England. More than 500,000 specimens of a single species of para- 

 site have been liberated in this manner during the summer of 1922, 

 and thousands of individuals of several other kinds have also been 

 liberated in this region. The present plans of the bureau include 

 the continuation of this work in order to insure, where possible, the 

 establishment of all available beneficial insect enemies of the pest 

 before it becomes widely distributed throughout the United States. 

 With this in view, what promise to be successful steps have been 

 taken to establish one species of these parasites on native corn borers 

 in the South Atlantic and Gulf States, so that this enemy may be 

 present and ready to attack the pest in case the European corn 

 borer should spread to those regions. 



Many other lines of investigation are being followed out to find 

 if possible sound means of control. Some of these are modifications 

 of farm practice, such as plowing under or burying infested stubble, 

 Aveeds, etc.. the feeding of infested forage to live stock, the effect 

 of placing it in silo, and its preparation by machinery for ensilage. 

 The use of chemicals as weed killers, to control the insect in weed 

 areas, is being investigated with some success. The variation in the 

 time of planting corn and the selection of varieties and the use of 

 trap crops are being studied, and insecticides are being investigated 

 as Avell. Every possible line of research which may lead up to means 

 of control is being followed up. 



A reduction of $75,000 which was made in the appropriation for 

 the fiscal year ending June 30, 1923. will render difficult the proper 

 carr3dng on of all the important work which ought to be done, espe- 

 cially in view of the comprehensive scouting and other operations 



