April, '10] DAVIS : ILLINOIS INSECTS 183 



The southern fern cutworm (Callopistria floridensis Guen.) is an 

 insect which has only recently made its appearance as a destructive 

 pest of greenhouse ferns, especially the Boston ferns. It was first 

 reported from Onarga, 111., in 1907, and since then it has required 

 strict vigilance on the part of the Onarga florist and two other florists 

 in Chicago to keep it from destroying their entire stock. Although 

 only known to occur in these three greenhouses, in Illinois, it is a 

 pest of much importance where found. This species was described in 

 1852 by Guenee from a single male collected in Florida, and, so far as 

 we have been able to learn, it was not reported again until this year 

 in the Yearbook of the U. S. Department of Agriculture for 1908, 

 where the Bureau of Entomology reports it as a destructive insect 

 on ferns in Washington, D. C, greenhouses. Our experiments show 

 the use of pyrethrum spray late in the afternoon or in the evening, 

 together with the trap lantern, to be the best means of combating 

 them. 



The onion thrips {Thrips tabaci Lind.) is the most generally de- 

 structive pest known to the Illinois florist, roses and carnations being 

 seriously damaged. They are abundant every year, and especially 

 so during the early and late summer months. Nicotine extracts are 

 the most generally used and have given the best satisfaction. Clean 

 cultivation in and around the green houses is of much value. Our 

 experiments show the thrips to be most active on the outside of the 

 buds early in the morning, consequently spraying or fumigating at 

 that time of day is desirable. 



The greenhouse thrips (Heliothnps hceniorrhoidalis Bouche) is 

 only occasionally injurious. The past year it has been found damag- 

 ing the Norfolk pine, smilax, and calla lily. 



Annually for the past ten or twelve years the rose-midge (Neoce- 

 rata rhodophaga Coq.) has been the cause of thousands of dollars loss 

 to several Chicago rose growers. This insect is not so prevalent now 

 as in former years, because most of the florists who were at one time 

 troubled with it have either discontinued growing roses or have 

 changed the crops grown in previously-infested ranges. In other 

 words, those florists who are now troubled with this pest have been 

 growing roses continuously in those houses originally infested or in 

 nearby houses. Where this species occurs it is the most destructive 

 greenhouse pest known. Hydrocyanic acid gas was thoroughly tried, 

 but it was ineffective against the maggots at a strength which would 

 not kill the plants. 



The cabbage plutella (Pliitella muculipennis Curt.) has made its 



