DESTRUCTION OF FLY LARV^ IIST HORSE MANURE. 17 



alkaloidal content; the two samples contained 0.25 and 0.41 per cent, 

 respectively, and no differences in larvicidal action were evident. 



The powdered hellebore used in the other experiments at New 

 Orleans contained 11.49 per cent of ash, 1.04 per cent of total nitro- 

 gen, and about 0.2 per cent of total alkaloids. The ground hellebore 

 used contained 29.39 per cent of ash, 1.08 per cent total nitrogen, and 

 0.2 per cent total alkaloids. It is therefore likely that commercial 

 powdered hellebore of reasonable purity will be effective as a larvicide 

 if applied as directed (p. 19). 



General discussion of hellebore. — There are three plants which are 

 popularly called hellebore, namely, Veratrwn album, Veratrum viride, 

 and Helleborus niger. The term " hellebore" is correctly applied only 

 to Helleborus niger, which grows in Europe and is not at the present 

 time a commercial product in this country. The white and the green 

 are the two commercial varieties, the white being largely imported, 

 and the green the American plant. For insecticidal work these two 

 varieties are considered equally valuable. The American hellebore 

 {Veratrum viride), called "swamp hellebore," u Indian poke," and 

 "itch-weed," is a common plant in wet ground and grows over a con- 

 siderable area of the United States. The properties of this plant are 

 said to be similar to those of white hellebore. A number of alkaloids 

 are claimed to have been separated from these two plants, but there 

 is some uncertainty as to their identity and activity. Powdered 

 hellebore, both the white and the green, is extensively used as an insec- 

 ticide against the currant worm and to kill various insects around the 

 roots of plants. Both varieties of hellebore are used in medicine to 

 some extent. 



OTHER PLANT MATERIAL. 



Oxeye daisy. — Tests were made with the ground flowers of the 

 oxeye daisy {Chrysanthemum leucanthemum) , using 1 pound to 10 gal- 

 lons of 1 per cent sulphuric acid. The material was extracted for 12 

 hours, and the extract was used undiluted and diluted 1 to 5. The 

 larvicidal results were practically negative in both cases, but as the 

 manure used in this experiment was lightly infested with larvae and 

 the results hardly warrant any definite conclusions. Bacteriological 

 and chemical examinations were made of the manure treated with 

 the undiluted extract. The bacterial count of the manure was some- 

 what lower than the controls, while the only noticeable change in 

 chemical composition was a decrease in the alkalinity due to the acid 

 in the extract added. The oxeye daisy contains a volatile oil but no 

 alkaloid has been found. 



Pyrethrum. — Pyre thrum (Crysanthemum cinerariaefolium) powder 

 was tried and two results from open-pile tests at New Orleans show 

 that solutions containing 0.5 pound per 10 gallons of water had no 

 larvicidal action (Table V, series 52, C and D). Pyrethrum contains 

 a volatile oil, and an alkaloid has been detected by one or two 

 investigators. 



