THE FRUIT-TREE LEAF-ROLLER. 



(Archills argyrospila Walker.) 



Ordei — Lepidoptera. Family — Tortricidae. 



By Geo. P. Weldon, Chief Deputy State Commissioner of Horticulture, Sacramento, Cal. 



Introduction. 



This pest is frequently reported as injuring the foliage and fruit of 

 various trees in different parts of the country, often becoming so 

 abundant that acres of orchards are defoliated and the crop ruined. 

 In New York State, Colorado, and New Mexico orchardists have known 

 of its ravages for many years. It is not a pest that commonly remains 

 bad in one place for a number of seasons, but when at its height there 

 are few that can do more injury in a short time. For years it may 

 occur in a locality and its presence will not be known by the orchard- 

 ists ; suddenly it begins to increase in numbers until it becomes a pest 

 of the greatest importance and control measures are necessary to check 

 it. Usually after from two to five years of its destructive work par- 

 asites have multiplied to such an extent that it is practically eradicated 

 by them, and for a number of years there may be little or no damage 

 from it. When conditions happen to be just right again, there will 

 be an increase in numbers and thus there are cycles of good and 

 bad years. 



Occurrence in California. 



On June 24th in company with State Horticultural Commissioner, 

 Dr. A. J. Cook, and County Horticultural Commissioner from San 

 Diego County, Mr. H. A. Weinland, the writer visited several orchards 

 in the vicinity of Julian. In one of these the leaf -roller had ruined 

 much of the fruit, the damage being more noticeable because of a light 

 crop. The foliage was also damaged to a considerable extent. We 

 were told that last season the insect had made its appearance in orchards 

 of this same locality but in lesser numbers. At the time of our visit 

 many moths, a few larvge and pup^ and an abundance of freshly laid, 

 eggs were seen. Not much has yet been determined in regard to the 

 distribution of this pest in the State. A few egg-masses have been seen 

 on trees in a number of places, and an unauthenticated report of 

 severe injury has come from a locality which we have not yet had a 

 chance to visit in order to determine whether or not the pest which 

 did the reported damage was the leaf -roller. 



Occurrence in Other States. 



In 1891 Prof. C. P. Gillette, of the Colorado Experiment Station, 

 published a bulletin, No. 19, in which he told about a serious outbreak 

 of the pest in northern Colorado. For about four years his records 

 show that it was bad, then larva parasites appeared which soon over- 

 came it, and since then it has not been a pest of any consequence in 

 that particular locality. In Bulletin No. 311 of the Cornell Experiment 

 Station, Prof. Glenn W. Herrick describes the pest and its ravages in 

 New York and other Eastern States. Mr. John B. Gill, of the Bureau 

 of Entomology, made studies of this insect in Colorado and New Mexico 



