Malathion 
Malathion at 7.5 1b/A did not affect Eisenia foetida in pot 
experiments lasting 2 months. Using rates of 16, 32, and 64 1b/A, a 
96-hour LD59 of 37.9 1b/6-in A was established. 
Hyche (1956) tested 1% and 24% emulsion sprays of malathion 
on earthworm beds in his search for a chemical to control mites. Both 
of these rates of application (242 and 605 1b/A respectively) signifi- 
cantly reduced the worms. The spray was applied at a rate of 1 gal/12-15 
sq ft. He did not report a level that was nontoxic to the earthworms. 
Martin and Wiggans (1959) found malathion in solution nontoxic 
to Eisenia foetida (sp.?) at the 0.1 ppm level but toxic at the 1 ppm 
level. The worms were immersed in the solutions for 2 hours and then 
checked 24 hours later after remaining in a peat moss medium dampened 
with the solution. Mortality of the worms was 60% at 1 ppm and 100% at 
10, 100, and 1000 ppm. 
Parathion 
Goffart (1949) found solutions of parathion more toxic to 
earthworms than dust-soil mixtures in laboratory tests. Mortality was 
10% in 2 days in one part parathion dust per 1000 parts soil (1000 ppm); 
it was 90% in 3 days in a 0.001% solution (10 ppm), with exposure to 
immersion lasting only 10 minutes. 
Schread (1952) used parathion (plus chlordane) to control 
Pheretima hupeiensis on golf greens. Between May 13 and June 24, 
94.5 1b/A of parathion was applied to a heavily infested golf green. 
Last counts indicated a 97% mortality by June 28. The treatment included 
17 1b/A of chlordane in June. On July 14, the top inch of soil contained 
30 ppm parathion. In June, 3 years later, worms still were absent from 
this green. 
Hyche (1956) conducted a series of experiments to find methods 
for controlling mites in earthworm beds without killing the earthworms. 
His tests with parathion showed that such differential control was possible 
with certain concentrations of the chemical. Treatments at 7-9 1b/A 
(Using 1 pint 25% emulsifiable concentrate or 2 lb 15% wettable powder 
per 100 gal water) were effective against mites without killing the worms. 
Higher rates (approximately 242 1b/A in the form of 1% emulsion) killed 
both earthworms and mites. Tests of a mixture of methyl parathion (24.5%) 
and parathion (6.2%) in emulsion gave results similar to those for parathion 
alone. 
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