THE PLUM LEAF-MINER 



Nepticida slingerlandella Kearfott 



Order, Lcpidoptcra Family, Tineidae 



C. R. Crosby 



This bulletin treats of a new insect enemy of the plum and prune. The 

 late Professor M. V. SHngerland first took up the study of the plum leaf- 

 miner in October, 1907, and continued the work with the assistance of 

 the writer during the following year. In February, 1909, Professor SHnger- 

 land made plans for publishing the results of this work in bulletin form, 

 but illness prevented the preparation of the manuscript; his untimely 

 death occurred a few weeks later. During the past two years the writer 

 has made further observations on the habits and life history of this moth, 

 and has, in cooperation with C. M. Hooker & Sons of Rochester, N. Y., 

 conducted experiments in the control of its ravages. In preparing the 

 following account, full use has been made of Professor SHngerland 's care- 

 ful and extensive notes and most of the illustrations are taken from his 

 photographs. The drawings were made by Miss Anna C. Stryke. 



In an address given before the Eastern Meeting of the New York State 

 Fruit Growers' Association at Poughkeepsie, February 10, 1909, Pro- 

 fessor SHngerland gave a brief account of the plum leaf -miner, which was 

 published in the Proceedings of that Association for 1909, p. 122. 



NATURE OF THE INJURY 



The plum leaf-miner in its injurious stage is a smooth, greenish white 

 larva, one sixth inch or less in length, found during late June and early July 

 feeding between the outer layers of the leaf. Hatching from an egg 

 attached to the under surface of the leaf, the larva penetrates the tissue 

 and first eats a narrow linear mine an inch or less in length, then widens 

 the mine so as to produce an irregular, more or less ovate blotch about 

 one half inch long. The part of the leaf so injured turns brownish and 

 dies. From three to twelve mines are often found in a single leaf. The 

 trees become partially defoliated and the fruit may fall prematurely. 

 When continued for a series of years this injury tends to weaken the vitality 

 of the tree and to injure the size and quality of the crop. Fig. 25 shows 

 a French Damson plum tree badly defoliated in the top. This photo- 

 graph was taken September 24, when uninfested trees were still in full 



foliage. 



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