﻿STBAWBERRY ROOTWOBM OK GREENHOUSE ROSES 



Va., on July 25 revealed the seriousness of the injury and the reason 

 for the appeal for assistance. The stock in eight large houses suf- 

 fered infestation, five, of the open-range type, being extremely heavily 

 infested. The damage was caused mainly by the adults, which were 

 present in unusually large numbers. As a result of their voracious 

 feeding practically all of the foliage was badly perforated and 

 ragged (fig. 1). In addition, a large proportion of the young shoots 

 had the wood badly scarred and girdled, giving it a very unsightly 

 appearance. It was found that the adults had a marked preference 

 for this new wood, of which there was an abundance at this par- 

 ticular season, owing to 

 the fact that the roses were 

 being forced vigorously. 

 Further examination 

 showed that the larvae had 

 also been feeding on the 

 roots (fig. 2) earlier in the 

 season. As a result of 

 these injuries a gradual 

 killing of the affected parts 

 ensued, producing a stunt- 

 ed growth of the plants. 

 In attempting to establish 

 the possible origin of the 

 infestation in Alexandria, 

 records by A. D. Borden 

 showed that this insect had 

 been attacking roses in the 

 same houses three years 

 previously. Recent evi- 

 dence disclosed that the 

 soil in which the roses 

 were growing had been in 

 the benches since then; 

 hence it seems that their 

 occurence dated back to 

 that time. 



Judging from the report 

 made by H. F. Deitz, the 

 Indiana infestation obvi- 

 ously was not so severe as 

 the one at Alexandria. It 

 was learned from the florist, however, that serious injury had occurred 

 during May, the injuries being confined to Killarney rose plants 

 growing in a solid bed in one of the five open-range houses infested. 

 The condition there was similar to that existing at Alexandria, since 

 the plants had been forced for about three weeks and had put forth 

 an abundance of young, tender shoots. In the same locality Dietz 

 noted this insect feeding on the foliage of out-of-door roses "grow- 

 ing next to a large strawberry bed, the leaves of which were badly 

 riddled b^ the beetles." 



Early in November, 1919, specimens of the strawberry rootworm 

 were collected in the rose houses of the United States Botanical 

 Garden at Washington, D. C, where they were doing serious injury. 



Fig. 2. — Roots of rose plant devoid of rootlets and 

 severely injured by larvae of the strawberry 

 rootworm 



