244 HORTICULTURE FOR SCHOOLS 



facts set down in this chapter are brief summaries, dealing 

 with a few insect groups, but there are thousands on thou- 

 sands of different species, many of which are an economic 

 menace to the horticulturist and all of which furnish fruitful 

 material for study. 



EXERCISES 



EXERCISE I. Study of the codlin-moth. 



Materials. "Wormy" apples or pears; knife; a few collecting 

 bottles or small vials partially filled with 3 to 5 per cent solution of 

 formalin. 



Procedure. Remove the codlin-moth larva from the apples or pears 

 by cutting them first into halves. Make careful drawings of the 

 burrows of the larva in the fruit. Draw a larva. Describe the appear- 

 ance, including the size, color, and shape. Notice the entrance hole 

 through the side or end of the fruit, and the mass of frass around 

 the core. Read as many references on the codlin-moth as possible. 

 Include in your notes facts relating to its distribution, a list of 

 the kinds of fruits attacked by it, and an account of the best methods 

 of control. 



EXERCISE II. Study of apple-tree borer. 



Materials. Sharp knife; trees infested with borers; vials filled with 

 3 to 5 per cent solution of formalin. 



Procedure. (1) Examine trees infested with the borers. Notice the 

 excrement or castings at the base of the trees infested with borers and 

 the discoloration of the bark above the burrows. (2) With the knife 

 cut out some of the borers and preserve them in the vials containing 

 formalin. Make drawings of the borer and describe it briefly. Read 

 as many references as possible on the borer. Include in your notes 

 the life history, habits, and control measures for the borer. 



EXERCISE III. Study of red-humped caterpillar, tomato-worm, or 

 other larvae. 



Materials. Small bottles containing 3 to 5 per cent formalin solution; 

 infested plants or trees. 



Procedure. Study the type and extent of the injury done by the 

 larva. Note its mouth-parts. Preserve some of the larvae. Write a 

 complete account of the nature of the work of the insect, its life history, 

 distribution, food plants, and control measures. 



