UNITED STATES DEPARTMENT OF AGRICULTURE, 

 BUREAU OF ENTOMOLOGY , 

 WASHINGTON, B. C. 



January 15, 1924. 

 Forest Entomology Brief 55' 



DEFOLIATION OP DECIDUOUS TREES. 



Leaf eating "by caterpillars, similar insect larvae, and adult 

 "beetles is the most evident, frequently observed, and often complained 

 of form of insect attack on shade and ornamental trees. A single de- 

 foliation of trees which naturally lose their leaves in the autumn is 

 not a very serious injury, particularly when it occurs in late summer. 

 Trees so defoliated usually leaf out the next year and show little or 

 no ill effect from the attack. "Then the leaf eating occurs early in 

 the year, completely strips the trees, and is continued year after 

 year, the results will be more serious. The trees may be stunted or 

 deformed or may die, either from exhaustion or as a result of other 

 insect injuries. 



Leaf-eating injury to shade and ornamental trees and shrubs may 

 be prevented to a great extent by thoroughly spraying the trees, 

 about the time the young caterpillars or other insects first appear, 

 with a lead arsenate solution, prepared according to the directions 

 in Forest Entomology Brief kO. 



Some accessory methods are- also available for successful use 

 under certain conditions or for some species of defoliators, such as 

 clipping off infested foliage with a long tree pruner and burning; 

 burning webs and caterpillar masses with an ignited kerosene- soaked 

 rag on a pole (care being used not to scorch or bum the bark); 

 crushing clustering caterpillars; banding trees with a sticky tree- 

 banding material; burning or otherwise destroying egg messes and 

 cocoons. Advice concerning the use of these methods can of course 

 only be given when the insect attacking the tree is positively known 

 as the result of an examination of .specimens submitted, or, in rare 

 instances, when descriptions given are sufficiently accurate for 

 recognition. Any of the accessory methods suggested above when 

 underlined are considered advisable in combating the species involved. 



WILLIAM MIDDLST01J, 



Specialist in Shad e-Tree Insects. 



Approved: 



P. C. Craighead, 



Entomologist in Charge of Forest Insect Investigations. 



E-243 



