Rearing Macrocentrus ancyIivoru< 



Breeding material from wliicli the parasites were secured for liberation in Massachusetts 

 peach orchards. 



More than 150,000 strawberry leaves infested by parasitized larvae of the strawberry leaf 

 roller, an alternate host of Macrocentrus, were collected in New Jersey and shipped to the lab- 

 oratory at Amherst. The parasites emerged from these leaf roller larvae. It was necessary to 

 keep this material at moderate temperature and high humidity until parasite emergence was com- 

 pleted, in order to prevent premature death of the leaf roller larvae and to insure maximum em- 

 ergence of Macrocentrus. 



Upon emergence the parasites, attracted by the light, clustered upon the screen at the only 

 undarkened window in the breeding room. They were drawn off the screen by the suction of 

 electric motors into cardboard cartons and were stored in a cooling room to keep them inactive 

 and in dormant condition until taken into the peach orchards and released. 



