U. S. D. A., B. E. Bui. 116, Part V. D. F. I. I., Issued March 12. 1913. 



PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



THE FRUIT-TREE LEAF-ROLLER. 



(Ar chips argyrospila Walk.) 



By John B. Gill, 

 Entomological Assistant. 



INTRODUCTION. 



Until quite recently the fruit-tree leaf-roller (Archips argyrospila 

 Walk.) has been looked upon as an insect of only minor importance 

 to cultivated crops. During the past few years, however, it has 

 become unusually abundant and has caused considerable loss to fruit 

 growers in certain sections, notably in Colorado and New Mexico and 

 in New York State. The most serious outbreaks have appeared in 

 Colorado in Fremont, Pueblo, and Montezuma Counties, and in New 

 Mexico in San Juan and Kio Arriba Counties. The investigations, 

 detailed in this paper, have been confined for the most part to the 

 infestations at Canon City, Colo., and Espanola, N. Mex. In the 

 former place the damage has been large, as the insect has appeared hi 

 serious numbers in about 1,500 acres of bearing orchards in what is 

 locally known as the Lincoln Park section, and it is also spreading 

 rapidly into adjacent fruit districts. If not checked the amount of 

 loss that will be occasioned by its attacks in the future will probably 

 be much greater than in the past. At Espanola, N. Mex., a com- 

 paratively small fruit belt, the infestation has not been so serious. 

 The damage incurred by the leaf-roller has varied from 25 to 90 per 

 cent of the entire fruit crop, depending on the measures of control 

 adopted, the abundance of the "worms," and the kind or variety of 

 fruit attacked. In unsprayed orchards the writer has seen the entire 

 fruit crop ruined by the larvae, and the trees completely defoliated 

 so that not a green leaf could be noticed. When trees are so defoli- 

 ated it is hardly possible for them to produce fruit buds for the fol- 

 lowing season. 



In speaking of the appearance of the fruit-tree leaf-roller in New 

 York Prof. G. W. Herrick says : 



In the spring of 1911 the larvae of this insect appeared in enormous numbers in the 

 orchard of Mr. W. 0. Page at Bethany Center, N. Y., and to a considerable extent in 

 neighboring orchards. Moreover, the apple leaf-roller was not confined by any means 

 to a small and limited area, but the larvae were found in many orchards of New York 

 in varying numbers. 



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