INSECT PEST SURVEY BULLETIN 
Vol. 20 Supplement to No. 9 December 10, 1940 
COLONISATION OE EUROPEAN CORN BORER PARASITES IN 19)40^ 
By C. A. Clark and W, G, Bradley, associate entomo.loglsts , 
Division of Cereal and Eorage Insect Invest i gations 
Bureau of Entomology and Plant Quarantine 
United States Department of .Agriculture 
The 1940 colonization program for corn Lorer parasites empha, sized the 
recolonization of the egg-larval parasite Chelonus nnnulipes Wesrn. in the 
Hudson River Valley in New York State and the distribution of the larval pa.ra~ 
site Macrocentrus gifuensis Ashxn. in Massachusetts, Rhode Island, Connecticut, 
eastern New York, and New Jersey. 
One hundred fourteen colonies, totaling 112,711 individuals of C_. annul ip 
were liberated during 1940. The size of colonies ranged from 739 to 2 , 24-7 
adul t s , including both sexes, but most ■ colonies consisted of approximately 
1,000 parasites. Of the liberations made, 110 colonies or 109,213 adults were 
released in the Hudson River Valley in Albany, Columbia, Dutchess, Greene, 
Orange, Rensselaer, and Ulster Counties, N* Y. , where work with this pamsite 
was concentrated this season. It was planned to release "a line of colonies 0: 
this parasite extending approximately BO miles on either side of the Hudson 
River, with the individual colonies spaced at 2-mile intervals. . It was be- 
lieved that this procedure would provide an optimum opportunity for the estab- 
lishment, dispersion, and rapid attainment of maximum effectiveness of the 
parasite. In general,' this plan was carried out but lack of host material, 
■unsuitable topography, and other factors made some modification of the prograx 
necessary in actual practice. Availability of the parasite in larger numbers 
than anticipated made it possible to make a second series of releases on both 
sides of end several miles back from the Hudson River. The territory from No’ 
burg to Cohoes (north of Albany) on the west side of the river and from Beaco? 
to Troy on the east side, and extending up to 10 miles from the river, was 
colonized with C_. ennulipes during 1940. 
Three colonies, totaling 1,251 adults, of C. annulipes were released in 
Atlantic Township, Monmouth County, N. J. One colony of 2,247 adults of this 
parasite was released in Berlin Township, Erie County, Ohio, as a further tes* 
of this parasite in the western part of the area infested by the European cor) 
borer. 
The releases of £. ennulipes during the 1940 season were perfectly timed 
to synchronize with host development in the releo.se territory. It is known’ 
that the adults of this species live for at leo.st 10 days or irmre under normal 
i/Eor previous releases of European corn borer parasites in the United State 
see Insect Pest Survey Bui., Sup. to No. $, vs. 18 and 19, 1938 and 1939* 
-533- LIBRARY 
STATE PLANT BOARD 
