NEW YORK STATE MUSEUM 2'J 



under favorable conditions, though it should be noted that the 

 greatest damage is limited to the early planted corn. There is a 

 possibility, if not probability, of approximately equally great injury 

 in at least a portion of the single brooded areas in New York State 

 and on that account it is believed that corn growers might well 

 adopt such modifications in agricultural practice as are likely to give 

 protection against this insect without involving an unreasonable 

 expense. 



Description, life history, etc. The signs of infestation, the 

 characteristics of the insect and its life history have been outlined 

 so fully in the Thirty-fourth Report of the State Entomologist for 

 1918 and the recently issued Cornell Extension Bulletin 31, that it 

 appears unnecessary to repeat the information at this time. 



Natural enemies. Although several natural enemies have been 

 noted, the probabilities of successfully controlling the European 

 corn borer by such agencies are not particularly promising for the 

 near future. It will certainly require a few years to introduce and 

 establish effective natural enemies, even if they can be found in 

 other countries. 



The minute ^%^ parasite, Trichogramma minutum 

 Riley, so destructive to the borer in Massachusetts areas in 1919, 

 is a common egg parasite of some forty-five dififerent hosts belong- 

 ing to four orders of insects, among which may be mentioned the 

 currant worm, the monarch butterfly, the fall webworm, the brown- 

 tail moth, the cotton moth, the corn ear worm, the fall army worm, 

 the grapeberry moth, the sugar cane borer or the larger corn stalk 

 borer, the oblique banded leaf borer and the locust leaf miner. 

 These are all common insects, most of them becoming exceedingly 

 abundant at frequent intervals; and this alone would indicate that 

 while Trichogramma is sometimes abundant and beneficial, it is 

 very rarely sufficiently numerous to control for more than a short 

 period one or more of these insects and that, generally speaking, 

 it is an unreliable parasite with habits which would hardly justify 

 the expectation of moderately satisfactory control. 



Control measures. It is obvious that national and state agencies 

 can not indefinitely continue to clean up the constantly increasing 

 infested areas and it therefore follows that repressive measures 

 which appear practicable to the farmer must be devised or serious 

 losses may follow. The most promising of these are given below. 

 In this connection it seems advisable to emphasize the fact that 

 special attention should be given to early planted corn, because this 



