June, '13] HASEMAN: UXSPOTTED TEXTIFORM LEAF MINER 313 



UNSPOTTED TENTIFORM LEAF MINER OF THE APPLE 



(Ornix geminatella Pack.) 

 By Leonard Haseman, Department of Entomology, University of Missouri 



The unspotted tentiform leaf miner of the apple has been exceed- 

 ingly abundant for the past two or three years throughout the apple 

 sections of Missouri. It has been gradually increasing in numbers 

 for three or four years and probably reached a climax the past summer 

 in this vicinity. In the orchard here on the horticultural grounds 

 it has been so abundant that during the months of September and 

 October it was almost impossible to find a single full grown apple 

 leaf which did not have from one to twenty mines. Fortunately 

 this type of leaf miner becomes most numerous from the middle to 

 the latter part of the summer and therefore is not as destructive 

 as it would be should its heavy work come earlier in the season. 



The unspotted tentiform leaf miner has been known to science 

 for many years, having been first imperfectly described by Packard 

 in his ''Guide to the Study of Insects" in 1869. Since that time a 

 number of other names have seemingly been applied to the same 

 species where it has been bred from the foliage of trees other than 

 apple. 



Life Cycle — For the past two years the writer has been studying 

 this pest in its relation to horticulture in Missouri. In this study a 

 number of interesting points have been determined with reference 

 to its life cycle and habits. The pest in this vicinity invariably 

 passes the winter in the pupal stage protected by a rather firm cocoon 

 which is made someAvhere along the edge of a leaf late in the fall. 

 After the first heavy frosts come the leaves containing the cocoons 

 and pupse fall to the ground where they remain throughout the winter. 



The past spring the first moths began to emerge in the insectary 

 on April 17 and on May 3 they were fairly abundant in the orchard. 

 From early May until late November either the adults or the cater- 

 pillars in the mines were found abundant here in the orchards. The 

 life cycle is completed in from four to five weeks and five fairly distinct 

 broods were made out in this latitude the past summer. The first 

 brood completed its cycle earl}^ in June and about the same date 

 each month following until October succeeding broods were to be 

 found. The broods overlap considerably so that the pest does not 

 have sharply defined generations but the periods at which the first 

 appearance of the heavy attack of succeeding generations is noted 

 may be rather sharply made out. 



