$6 NEW YORK STATE MUSEUM 



that there had been no spraying since 1900, at which time an effort 

 was made to destroy forest tent caterpillars with a contact insecti- 

 cide. The work of this apple enemy is easily recognized by its 

 trumpet-shaped mine which commences as a glistening spot where 

 the tgg was laid, continues for a short distance as a narrow line, 

 gradually expanding and then suddenly widens into an irregular 

 expanded portion. The mine is on the upper side of the leaf and 

 when old, turns brown and is scarcely seen from the under surface. 

 It is inhabited by a greenish, footless, active caterpillar. The upper 

 and lower walls of the mine are densely lined with silvery white 

 silk forming a winter retreat for the larva, which latter trans- 

 forms in the spring to the pupa at one end of the mine and in 

 a short time forces its way partly out through the upper surface of 

 the mine and then the moth emerges. 



This species appears on the foliage so late in the season that 

 comparatively little injury is caused and, as a rule, remedial meas- 

 ures are unnecessary. One method of controlling this insect in 

 case of necessity is to burn the fallen leaves which, as stated above, 

 contain larvae or pupae, and thus reduce the number of insects 

 another season. Spraying the foliage in summer with 10 to 15 

 per cent kerosene emulsion has also proved of value in destroying 

 the larvae in their mines. 



Palmer worm (Ypsolophus ligulellus Hub.). The 

 small, pale green or yellowish green, active, striped caterpillars of 

 this species aroused much interest in 1900 because of their ex- 

 treme abundance in orchards in Genesee county. This insect ordi- 

 narily escapes attention and, prior to the above mentioned out- 

 break, had scarcely been noticed subsequent to 1853. Palmer worm 

 larvae were rather generally present the latter part of June 1912 in 

 orchards in and about Byron and were found in small numbers 

 upon apple trees at Nassau. Apples with freshly eaten irregular 

 holes were noted near caterpillars, and one was found in a posi- 

 tion which suggested that it had just been feeding upon the fruit. 



The full-grown caterpillar is about half an inch long and is then 

 usually of a pale green or yellowish green color with a dusky, sub- 

 dorsal line. The head may be either yellowish or blackish. Though 

 there is considerable variation in color the larva is not difficult to 

 recognize, since it is very active and drops much in the same 

 manner as does the canker worm when disturbed. Leaves partly 

 skeletonized by this insect soon turn brown, curl and present an 

 unsightly, ragged appearance. It is interesting to note that the 



