ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 



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in diameter. The female overwinters as a partly grown insect 

 and reaches maturity in early spring. After mating, she gives 

 birth to living young: small, flat, yellow creatures, which crawl 

 out from under the mother shell. When a crawler finds a suitable 

 place, it settles down, inserts its threadlike beak into the bark 

 tissue, loses its legs and antennae, and starts making a shell for 

 its own protection. As the scale grows, its shell is enlarged and, 

 following a series of molts, the scale reaches maturity. The 

 fragile male scale develops wings and escapes from its protective 

 shell to mate with a female, which does not leave its shell. The 

 San Jose scale may produce several generations in a summer. 

 Control Measure 5 (end of circular) on dormant plants. 



Fig. 13. — Hawthorn leaf miner: larva and damage to hawthorn leaf. 

 The upper epidermis along one margin of the leaf is folded back to dis- 

 close the white larva (arrow) and its excrement. Along the opposite mar- 

 gin of the leaf is a dark blister, a sign of damage by the leaf miner. 



