AN INVESTIGATION OF THE SCARRING OF FRUIT CAUSED 



BY APPLE REDBUGS ' 



Harry H. Knight 



During the season of 19 14 the writer began an extensive series of 

 observations on the production and development of scars caused by 

 the various insects attacking the apple. The ultimate aim of this work 

 was to make it possible to recognize the scars on apples at picking time 

 and the insects causing them, so that the orchardist might deal more 

 intelligently with these obscure 'foes. The writer was able to carry on 

 this work under most favorable circtunstances in cooperation with the 

 Genesee County Fruit Growers' Association, spending all his time during 

 four growing seasons in orchards thruout Genesee County. Gratifying 

 results were obtained in the studies made on the sucking bugs Lygidea 

 mendax and Heterocor- 

 dyltts maliniis. The 

 present paper deals 

 chiefly with the inju- 

 ries produced by L. 

 mendax, since it was 

 found that H. malinus 

 is practically negligi- 

 ble in the production 

 of scars on the fruit. 



METHODS OF STUDY 



In conducting the 

 observations , large 

 shipping tags (fig. 22) 

 were used to keep ^^^- ^^- northern spy apple, showing the work of 



' LYGIDEA MENDAX AtiD THE METHOD OF TAGGING 



track of the injured 



apples. On these tags were written all data' regarding the time of injury, 

 and subsequently additional notes on the development of the scars. Large 

 numbers of fruits were tagged for each species of insect found at work in 

 the various orchards, and at short intervals thruout the growing period 

 specimens were picked and photographed so that a record might be kept 

 of each kind of injury in its various stages of development. It was found 

 that different varieties of apples when injured by redbugs would develop 



' Prepared for presentation in partial fulfillment of the requirements for the degree of doctor of philos- 

 ophy. The work was done under the direction of P.i essor Glenn W. Herrick. 



297 



