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The Wisconsin Agricultural Experiment Station (323) in 1938 
reported that the "best spray for protecting cattle against flies 
contained 5 percent of pyrethrum extract in a highly refined mineral 
-seal oil of viscosity 40 to 50. Among the materials that proved 
ineffective as a fly spraj^ insecticide in these tests were rotenone 
and other. derris extractives, sulfur compounds, and a number of 
synthetic insecticides. Several antioxidants, tested to learn whether 
they would prolong the effectiveness of insecticides, failed to improve 
cat tie- fly sprays. 
' According to the manufacturers, Dodge and Olcott Company, New York, 
N. Y, r in advertising literature published in 1939,. Rotopyressenol No. 20 
is a combination which "embodies in scientifically correct proportions 
the quick knock-d&wn' value of pyrethrum and the high moribund kill and 
leg paralysis of dihydrorotenone, both enhanced by the activative 
penetration of Essenol." D. and 0. Essenol is said to be en insectici- 
dally active combination of essential oils, and it is stated that the 
effective killing power of pyrethrum and rotenone sprays is substan- 
tially increased by its addition. • » 
Whitmire ( 318 ) in 1939 defined moribund flies as "those that can 
move some part of their bodies, but cannot fly or valk to an extent to 
•enable them to get off the observation paper." He described an apparatus 
and method for determining moribund kill. Rotenone and certain deriv- 
atives of it (e.g., dihydrorotenone) in fly sprays do not kill flies 
immediately but act slowly, producing moribund flies. 
In 1940 the Experimental and Research Station, Cheshunt, Herts, 
England ( 81 ) , reported that applications of -oyrethrum powder to mushroom ' 
beds had given results [against Diptera] as good as those obtained by 
atomization of pyrethrum and derris extracts with apparatus employed 
in the treatment of warehouses. 
An anonymous writer (8) in 1941 renorted that the name "Indalone" 
had been registered by U. S. Industrial Chemicals, Inc., Ne^ York, N» Y. , 
as the trade-mark of the solvent alnhe, alpha-dime thyl-al-oha'-carbobutoxy 
-gamma-dihydropyrone. Indalone, formerly marketed under the name "dihydro 
-pyrone," was developed for use in liquid contact insecticides as a 
solvent for derris-root extractives.' When used in this way it has the 
property of increasing the insecticide 1. effectiveness of the ingredients 
dissolved in it andof holding derris extractives in solution in the 
commonly used base oils. Indalone is a powerful insectifuge and repels 
the common winged insects, to Hiich it appears to have an obnoxious taste. 
Because of this high repellency, it is especially suitable for cattle 
sprays and mosquito lotions. 
