THE EUROPEAN CORN BORER AND ITS CONTROL. 59 



Summarizing the records of parasites bred from the European corn 

 borer it will be noted that there are four species of Diptera and two species 

 of HjTnenoptera represented. The number of different species attacking 

 P. nuhilalis suggests the possibility that parasites may in the future have 

 some influence in controlling the pest, but at the present time they cannot 

 be relied upon to accompUsh much. 



PREDATORS. 

 Birds. 



Several species of birds, including woodpeckers, blackbirds and crows, 

 have been observed to feed upon the larvae and pupse of the European 

 corn borer. Blackbirds have been observed to pick them out of infested 

 corn tassel-stalks, frequently breaking over the tassel-stalk to reach the 

 insect within. On one occasion a flock of crows settled down in an infested 

 patch of field corn and devoured nearly all of the P. nuhilalis larvae which 

 were feeding on the ears. Incidentally they also devoured some of the 

 corn. 



Insects. 



Larvae of the corn ear worm Chloridea ohsoleta Fab. frequently kill 

 and feed upon P. nubilalis larvae which are feeding on the same ear of 

 corn. 



A small beetle, Ips fasciatus, is frequently found in P. nubilalis tunnels 

 but has not been observed to prey upon the larva of the pest. 



CONTROL. 

 Destroying Plants containing Overwintering Larv^. 



Bearing in mind the life history and habits of the European com borer, 

 it is e\'ident that any measures for controlling the insect must be pre- 

 ventive rather than remedial. The most obvious method of preventing 

 damage by the insect, or at least greatly reducing its numbers, is by the 

 destruction of plants containing the overwintering larvae. This may 

 be accomplished any time during the period from the middle of October 

 until the middle of the following May. 



Burning Infested Plants. 

 Burning infested plants is undoubtedly the most practical and effective 

 measure that can be adopted for the destruction of the overwintering 

 larvae. At first thought this seems to be an easy method of handling the 

 problem, but when the great variety of food plants is considered, and also 

 the extent of the infested area (320 square miles), it becomes one of great 

 proportions. In order to destroy the larvae in any given area by this 

 method, all parts of the different food plants within that area must be 

 burned, including the roots or stubble of the plants. 



