ORNIX GEMINATKLLA, THE UNSPOTTED TENTIFORM 

 LEAF MINER OF APPLE 



By L. Haseman,^ 

 Entomologist, Missouri Agricultural Experiment Station 



INTRODUCTION 



The small, unspotted tentiform leaf miner (Ornix geminatella Pack.) has 

 been extremely abundant in Missouri in recent years and has attracted 

 the attention of fruit growers throughout the State. It has confined 

 itself largely to bearing apple {Malus sylvesiris) orchards, though con- 

 siderable injury has been done to apple foliage in nurseries. Fortu- 

 nately, it is most abundant in the late summer and early fall, so that its 

 work is of less importance to the trees. As with many insect pests, it 

 seems to run in cycles. It was most abundant during the summers of 

 191 1 and 1 91 2, reaching a climax in 191 2. Since 191 2 it has attracted 

 little attention. 



It confines its work to the leaves and spends most of its larval life 

 inside the leaf as a true miner. The caterpillar therefore is small, though 

 the characteristic elevated, or tentiform, dead patches which it produces 

 on the leaves are quite noticeable. In some cases as many as 15 mines 

 have been found on a single large apple leaf (PI. XXXIII, fig. 14, 15). 

 The pest was so abundant and so widely distributed throughout the 

 State that a careful study of its life history, habits, and control v/as under- 

 taken. 



HISTORY OF THE PEST 



The moth was first described and figured by Packard (7, p. 353)^ in 

 1 869 as Liihocolletes geminatella. The description and figures are incom- 

 plete and not entirely accurate, owdng perhaps to incomplete observa- 

 tions. Since its first discovery it has been collected by various workers 

 and was redescribed by Chambers (2) as L. prunivorella. Other closely 

 related micros have been mistaken for it, and some careful observers have 

 given very inaccurate descriptions of its v/ork and habits. 



DISTRIBUTION OF THE LEAF MINER 



Packard reported it as being abundant in New England on pear and 

 apple; Lowe (6) reported it as being very abundant on apple in New 



' The writer wishes to acknowledge his indebtedness to the late Miss Mary E. Murtfeldt, of Kirkwood, 

 Mo., to Miss Annette F. Braun, of Cincinnati, Ohio, and to Mr. August Busch, of the Smithsonian Insti- 

 tution, Washington, D. C.,ior assisting with the naming of the leaf miner; and to Dr. L. O. Howard. Chief 

 of the Bureau of Entomology, and to Mr. A. A. Girault, of the same Bureau, for the determination of the 

 parasites. He is also especially indebted to Prof. C. R. Crosby, of Cornell University, for helpful sugges- 

 tions and for assistance in naming the leaf miner and the parasites. 



' Reference is made by number to "Literature cited. " p. 295. 



Journal of Agricultural Research, Vol VI, No. 8 



Dept. of Agriculture, Washington, D. C. May 22, 1916 



dt Mo.— I 



(289) 



