Hoy (1955), working in New Zealand, made both laboratory and 
field tests of the effects of DDT on Lumbricus rubellus and Allolobophora 
caliginosa. In the laboratory tests, soil of low organic content was 
mixed with 10% DDT dust (para para' isomer) at rates of 21, 40, and 
80 1b/A. At the end of 8 weeks, earthworm populations were significantly 
lower in the jars treated at 80 1b/A but not in the jars treated at 
lower rates. 
In the field tests, DDT was applied at 2, 30, and 60 1b/A, and 
population counts were made at the end of 23 and 83 weeks. Worms were 
not completely eliminated; there were some significant differences, how- 
ever, but these possibly could have been the result of normal variation 
of earthworm population distribution. 
Hopkins and Kirk (1957) exposed Eisenia foetida to DDT (10% 
dust) at 15 1b/A for 2 months without any marked worm mortality. Tests 
were made in Marlboro sandy loam (South Carolina). They reported that 
tests with DDT up to 256 1b/A gave erratic results. 
Barker (1958) sampled soil and earthworms from beneath elm 
trees that had been sprayed with DDT for Dutch elm disease control. The 
soil samples contained up to 18 ppm DDT and/or DDE. Whole body analyses 
of earthworms (Lumbricus terrestris, L. rubellus, Helodrilus spp., and 
Octolasium lacteum) contained from 53-204 ppm (wet weight). The earth- 
worms appeared not to be affected; however, deaths of robins were believed 
due to consumption of toxicant-bearing earthworms. 
Martin and Wiggans (1959) tested the effects of DDT solutions 
on Eisenia foetida (sp.?). The worms were submerged for 2 hours in solu- 
tion of 0.1, 1, 10, 100, and 1000 ppm and then kept an additional 24 
hours in peat moss dampened with the solution. Survival counts were 
then made. There was no earthworm mortality at 10 ppm or lower. Mortality 
was 20% at the 100 ppm level and 60% at the 1000 ppm level. No attempt 
was made to correlate these results with field conditions or rates of 
field application. 
Edwards and Dennis (1960) reported. no effects on earthworms 
from soil treatments with 200 1b/A of 5% DDT dust (effective toxicant 
apparently 10 1b/A). The DDT was mixed to a 6-inch depth on plots 6 
feet square and all plots were kept fallow with herbicides (CMPP and 
Dalapon). Samples were taken at the end of 2 + 3 months. The earthworm 
species, soil types, and other details were not given. 
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