220 Bulletin 308 



history and food plants 



The plum leaf -miner is a new fruit pest and is doubtless a native Ameri- 

 can insect. Injury caused by this insect was first reported to Professor 

 Slingerland in the fall of 1907 by C. M. Hooker & Sons of Rochester, 

 N. Y., who stated that the leaf -miner had been present in their orchard 

 for a number of years and had been gradually increasing in numbers. 

 Mr. J. H. Stewart of Pittsford, N. Y., states that his father's extensive 

 prune orchard, situated about five miles from the Hooker orchard, has been 

 partially defoliated for the past three or four years, apparently by this 

 insect. 



That it may occasionally attack apple is quite probable. While examin- 

 ing some old apple trees in a neglected orchard about a quarter of a mile 

 from the Hooker orchard on July 7, 191 1, the writer found that mines 

 very closely resembling those of the plum leaf -miner were abundant 

 in the leaves of the water sprouts growing at the base of several trees. 

 Infested leaves were brought to the Insectary, but the larvse left the 

 mines while in transit and constructed cocoons indistinguishable from those 

 of the plum leaf-miner. The identity of this apple leaf-miner cannot be 

 settled definitely until the moths are reared next spring. 



In the Hooker orchard the plum leaf -miner has shown a decided prefer- 

 ence for certain varieties. German and Italian prunes are most severely 

 infested; French and Shropshire Damsons are less subject to attack, al- 

 though some years ago the former variety was badly infested; Diamond, 

 Bradshaw, Lombard, and Rheinclaude are nearly immune. 



LIFE HISTORY 



The moth. — The adult of the plum leaf -miner is a small bronzy black 

 moth having an expanse of one seventh to one fifth inch (Figs. 32 and 33). 

 The fore wings are crossed by a shining white band on the outer third, and 

 the head bears a conspicuous orange tuft. These moths emerge from 

 cocoons at or near the surface of the ground during the daytime in the 

 latter part of May and in early June. During the day they remain quietly 

 on the bark of the trunk and larger branches, none being found on 

 the leaves. Several hundred moths are often found on a single tree; when 

 disturbed they suddenly take flight and most of them settle on the op- 

 posite side of the tree. They gradually decrease in numbers, and about 

 the middle of June they disappear. The technical description of the 

 moth as given by W. D. Kearfott (Jour. N. Y. Ent. Soc. XVI, p. 187, 

 1908) is as follows: 



" Nepticula slingerlandella new species. 



" Expanse 3.5 to 5 mm. 



