- 9 - 
treatments protected the plants. Pure dcrris powder applied to caTD"bagc 
plants destroyed 4 percent of tha plants in two tests. Dcrris (3 pounds to 
100 Imperial gallons) poured abcrut plants previously infested v/ith 25 
fully grovm cabbage maggots of the first brood prevented none of the larvae 
from pupating. Onion maggot larvae, Hy 1 emya ant i qua Meig. , immersed for 5 
seconds in derris solution (3 pounds derris to 100 imperial gallons) and 
then allowed to remain unmolested 1 week upon the food plant were affected 
as follows: 
Age of larvae Percentage dead or Age of larvae Percentage dead 
missing in 1 week or missing in 1 week 
1 day 100 10 days 35 
4 days 100 15 days 25 
7 days lOO Full grown 
1922 
Treherne (95) in 1922 suggested the separation of the essential oils or 
extracts of plants in order to prepare liquid sprays or medicated powders 
which would act negatively chemotropically in insect pests, as has been done 
with tobacco, pyrethrum, hellebore, derris, and certain other substances. 
The Federated Malay States Department of Agriculture (29) in 1922 re- 
ported that for dealing with the pest Nymphula depunctalis Guen. in the padi 
nurseries spraying v;as being carried out with a decoction of tuba root. 
Bishopp, LaaJke, and Wells (7) in 1922 stated that a single application 
of derris in soapy water applied with a brush to the backs of infested animals 
had been found to kill almost 100 percent of Kypodorma larvae. 
Wells, Bishopp, and Lnakc (109) in 1922 reported the results of tests 
of powdered derris root against certain external parasites of animals. When 
chickens infested with 7 species of lice (Mallophaga) were rather thoroughly 
dusted with derris the lice were very quickly destroyed, practically all of 
them being dead the day following treatment. Subsequent examinations extend- 
ing over a period of 6 weeks shovied no live lice present, thus indicating 
that the eggs were killed or the yo-ung lice destroyed upon hatching. All lice 
were killed 3 days after dipping fowls in a bath of l/4 ounce of powdeyed 
derris in 1 gallon of v/ater. 
Derris proved effective against the common biting louse of cattle, 
Bovicola bovis L. Derris powder, 1 ounce per animal, applied with a dust gun 
killed all lice and their eggs, A mixture of derris with an equal quantity of 
flour applied at the rate of 1 ounce or 1.5 oxinces per animal also killed 
all lice and their eggs. A mixture of equal parts of derris and sodium 
fluoride dusted on calves at the rate of l-3/l5 ounces per animal killed all 
lice. A mixture of equal parts of derris and tobacco dust, the latter con- 
taining about 0.1 percent nicotine, killed all adult lice, but some of the 
eggs escaped destruction. Mixtures of derris, 1 part, and tobacco dust, 
10 parts; and of derris, 1 part, and flour, 3, 5, 10, or 20 parts, killed 
most but not all of the lice. 
