I',ln4. 



The Weekly Florists' Review* 



1045 



located where water power makes cheap 

 electricity would this not be practica- 

 ble? J. E- K. 



A SERIOUS ROSE PEST. 



In recent years several of the large 

 rose growers in the vicinity of Chicago 

 have Ijeen troubled with minute larva; 

 which destroyed the buds and delicd all 

 efforts at eradication. An appeal to the 

 Illinois State Laboratory of Natural His- 

 tory at the State University resulted in 

 an investigation by F. M. Webster, il. A., 

 who classified the rose midge and lias 

 now published an illustrated bulletin on 

 it. He describes the midge and lar\ic 

 at length, so that growers who have met 

 the pest will Jind it easily recognizable, 

 but he does not name a practical rem- 

 edy. The larvie are ''very tenacious of 

 life." he says, and the growers will bear 

 bim out in his statement. Hydrocyanic 

 acid gas will kill them if exposed, but 

 not tliose working in the' buds. 



The co]nplete bulletin Avill be sent to 

 those who address the State Laboratory 

 at L'rbana, III. The less technical parts 

 follow: 



About the year ISO", in the vicinity of 

 Chicago, III., certain varieties of roses 

 grown imder glass, notably the Meteor, 

 were attacked by great numbers of min- 

 ute cecidomyian larvte which destroyed 

 the terminal leaf and blossom buds. In 

 the greenhouses of one extensive rose 

 grower, the injury was so severe as to 

 render the production of the Meteor un- 

 profitable, and he stopped growing it for 

 a time, until the pest seemed to have dis- 

 appeared. Strangely enough, another 

 i;rower, whose houses were separatcfl 

 from those of the first only by a narrow 

 alley, did not at that time suffer at all 

 from the ravages of the insect, but con- 

 tiimed to grow the Meteor in his rose 

 houses without difficulty until sometime 

 after, when he, too, began to experience 

 severe losses on account of its depreda- 

 tions. The species v\as not definitely de- 

 termined at that time, and it is impos- 

 sible in the light of later investigations 

 to say with certainty whether or not 

 more than one was engaged in these at- 

 tacks. Since then, however, a number 

 of extensive rose growers about Chicago 

 have been obliged to abandon the grow- 

 ing of this particular variety of rose on 

 account of its extreme liability to attack 

 from these larva\ 



In 1900, Mr. D. W. Coquillett pub- 

 lished a paper reporting similar injuries 

 to roses grown luider glass in Xew Jer- 

 sey in 18R6 and 1889: New York in 

 1890: Washington, D. C in 1891, 1894 

 and 1890; Boston in 1894. and Chicago, 

 as has been stated, in 1897. Apparently 

 the same species was sent to the United 

 States Department of Agriculture from 

 Cleveland. Ohio, in 1903. 



On Jlay 10. 1903, a firm located in 

 the vicinity of Chicago, engaged in grow- 

 ing roses extensively under glass, advised 

 the Illinois State Entomologist of serious 

 trouble among their ^leteors, evidently 

 due to a minute whi'" ■■ -'rm which at 

 tacked the buds and destroyed them. 

 Early in June. Mr. C. A. Hart, being in 

 that vicinity, visited the premises by Dr. 

 Forbes' direction, and brought some of 

 the affected buds to the office. The larva; 

 found in them were very small, white, 

 except those seemingly full grown which 

 were tinged with orange. 



The matter was now placed in mv 

 hands for investigation, and on June 11, 

 acting under instructions, I visited the 



Design for Funeral of M. A. Hanna. 



(By Wesunan ,V Getz. Cleveland.) 



lo.'^e houses containing the injured plants. 

 Larvae were found in the young rose- 

 buds of both leaf and blossom, but more 

 abundantly in the latter, and also eggs, 

 which, from their position in these buds, 

 indicated that they were those of the 

 same species as the larvae. Several very 

 minute female midge-like flies were also 

 taken, seemingly in the act of oviposit- 

 ing in the blossom buds. 



I have never seen the larvae nttackimr 

 the native wild roses, even about Chi- 

 cago, though, in the near vicinity of in- 

 fested rose houses. I have found them 

 in buds of the variety known as The 

 Bride, growing in the open air. The 

 manner of hibernation is not well under- 

 stood, but in the rose houses there is no 

 injury done by tlie larvae from late Oc- 

 tober imtil late' the following May. A 

 thorough inspection of large rose houses 

 about Chicago. November IS to 20. did 

 not reveal a single larva or adult, even 

 wdiere serious damage had been wrought 

 a few months before', and an inspection 

 made on January 29, 1904, also failed to 

 reveal their presence.. 



In the rose houses, the larvse attack 

 the ifeteor. Wootton. Bride, iladame 

 Chatenav, La France, Ivoiy and Colden 



Oate. but are far more fatal to the first 

 than to any other variety. The insect 

 Hist appears in such rose houses as are 

 old and more or less open on account 

 of cracks and crevices, or else in such 

 as are new and tight, requiring much 

 ventilation. In the case previously re- 

 ferred to, where only an alley separated 

 infested from iininfested ])remises. the 

 iininfested houses were given the least 

 |)ossible ventilation consistent with the 

 growth of the roses, while those infested 

 were more generally ventilated. Later 

 on. these conditions were reversed, and 

 the situation as to in.sects changed also, 

 the premises that had before escaped be- 

 insj- now overrun. 



An experienced foreman in the em- 

 ]iloy of a firm of extensive rose grower? 

 whose premises were infested with this 

 midge, informed me that the inject first 

 attracted his attention by attacking 

 those buds that were highest up and 

 nearest to the' glass, and that the larvfe 

 were only to be found in such buds as 

 were in close proximity to the glass, 

 those situated lower down not being at 

 all affected, thus indicating that one ros? 

 house may become infested from another 

 li\' adults, and not necessarily from thE> 



