Introduction 



EXPLANATION OF KEY FOR DETERMINING INSECT 

 INJURY TO SUGAR BEETS 



The method of using the Key (pages 5 to 8) is illustrated below 

 by imagining a case of injury and following it through the Key until 

 we come to the point where we get a clue to the insect causing the damage. 



Example: In going through the field while the thinners are at work, 

 we notice a beet here and there which is wilted and cut off just below 

 the surface of the ground. Take your Key and begin at "A." This 

 says that the leaves of the plant are wilted while those of the surround- 

 ing plants remain normal. This is true of the plants we found, so we read 

 what comes under "1." As our beet is cut off below the surface of the 

 ground "1" fits our case, so we continue to "a" and read: "Plants small. 

 Damage occurring before or shortly after blocking and thinning". As the 

 thinners are at work in our field this again fits our case, so we pass on 

 to the single star (*). Here we read: "Plants cut off at or just below 

 the surface of the ground," etc. This is our case exactly, and at the end 

 we read: "Look for Cutworms." Thus the Key indicates that cut- 

 worms are at work on our beets and refers us to pages 38 to 48 of the 

 Bulletin, where this insect is discussed. 



- Let us suppose that when we read the paragraph under the single star 

 (*) we found that this did not describe our beet. We would then pass 

 on to the double star (**), and if the beet we have has been injured by 

 any of the insects discussed in this Bulletin this paragraph should describe 

 the way it is injured. 



If the injury was not indicated by a wilting of the leaves we pass 

 from the capital "A" to capital " B", on page 6, and if this does not fit 

 our case we pass on through the capital letters until we do find the de- 

 scription. When we find it we pass through the other steps which are 

 indicated by figures, small letters, etc., until we come to the place where 

 the insect causing the injury is named. 



While this Key may not fit all cases exactly, yet it should enable 

 one to determine quite closely what insect is causing the injury noticed. 

 Then if the discussion of this insect and the nature of its injury are read 

 and the insect, if one is secured, is compared with the pictures in the 

 Colored Plates, there should be little difficulty encountered in identifying 

 the culprit. 



In case of doubt competent advice can always be obtained by con- 

 sulting the authorities of the agricultural colleges, county agents or the 

 sugar company's fieldmen. 



