December, '14] WEISS: AGRILUS ON ROSES 439 



that it was a European species. Dr. Chittenden mentions however, 

 that as far as he knows no one has ever studied the foreign species of 

 this genus in comparison with the native ones. Inasmuch as a con- 

 siderable amount of the injury occurred on standard roses which had 

 been imported from Holland in the spring of 1913, it was at first 

 thought to be an imported species. However, Mr. H. M. Quanyes,, of 

 the Phytopathological Institute of Holland, to whom I sent photo- 

 graphs of the gall and a description of the injury, replied that no such 

 insect work occurs in Holland on roses. 



Nature of Injury: The work of the larva is characteristic of an 

 Agrilus species and consists of a spiral band of channels in the sap- 

 wood, these channels being very close together for a distance of 

 from three quarters of an inch to two and one half inches. After 

 making these galleries, the larva, goes up the stem in a zigzag fashion, 

 sometimes just under the bark and other times irregularly through 

 the pith and sapwood for a distance of from three to six inches where 

 it constructs an overwintering larval chamber which serves for pupa- 

 tion in the spring, the adults emerging the early part of June. The 

 swelling or gall on the stem occurs over the spiral band of channels 

 and varies in size from being almost imperceptible to twice the dia- 

 meter of the stem, depending, of course, on the size of the larva and 

 its activity in making a spiral band. 



On Rosa rugosa, these swellings were sometimes marked by longi- 

 tudinal shallow splittings of the bark varying in length from one 

 eighth of an inch to one inch. On stems not as woody as those of 

 rugosa, the splittings were deeper and more open. As a rule, on Rosa 

 rugosa only one gall was observed to a stem and it occurred anywhere 

 from the ground up. In a few cases three or four were counted on a 

 rugosa stem and five on a Carolina. 



The leaves of the infested roses first turn yellowish, finally withering 

 completely and turning brown. The stem being weakened at the 

 swelling breaks off easil5^ At one nursery in New Jersey, $200 worth 

 of standard roses were destroyed because of this insect and at another 

 it required the services of two men for over two days to cut and burn 

 infested stock. 



Varieties Infested : Standard roses as a rule are grafted on rugosa 

 stock and Rosa rugosa seem to be particularly subject to attack. In 

 addition the insect w^as found infesting Rosa Carolina, Rosa blanda, 

 Rosa multijlora Japonica, Rosa rubrafolia, Rosa nitida, Rosa setigera 

 and wild roses. 



Distribution: In New Jersey, infestations were found at Ruther- 

 ford, Millburn, Springfield and Englewood. Mr. F. Windle, of West 

 Chester, Pa., has noted injury to Rosa rugosa in that vicinity. Mr. H. 



