EFFECTS OF CHEMICALS ON EARTHWORMS: 
A REVIEW OF THE LITERATURE. 
Stuart P, Davey 
Branch of Wildlife Research 
Bureau of Sport Fisheries and Wildlife 
Most tests of the effects of chemicals upon earthworms have 
been made with the purpose of learning how to control the earthworms 
in areas such as golf greens, where the worms are not wanted. Other 
tests have been made to learn possible effects of fertilizers on earth- 
worms in crop fields, where the worms are wanted for the good they may 
do in soil aeration and mixing. More recently, some tests also have 
been made to determine the effects on earthworms of pesticides applied 
for other purposes. 
The principal results of these studies, as learned from a 
review of the literature, are summarized here. For convenience of 
organization and reference, the review is arranged according to chemi- 
cal, rather than according to the purpose of the particular study. 
Chemicals are grouped as botanicals, inorganic chemicals, and organic 
chemicals. 
The difficulty of making dependable experimental studies of 
soil fauna and pesticides was discussed by Satchell (1955), who pointed 
out thwe.the apparent absence of effects sometimes may have been the 
result of poor experimental design in the face of highly variable 
population distributions. The problem also was discussed by Kuenen 
(1957), who noted that mortality of experimental animals was not 
normally distributed and that therefore there was not complete independ- 
ence of action between toxicant and mortality. A thorough review of 
the soil insecticides used from 1914 to 1940 was made by Gough (1945). 
This, of course, involved none of the modern chemicals, but nevertheless 
is of considerable value, The present review is intended to be 
descriptive rather than analytical, but so far as possible the facts 
that will affect a judgment are included. The species of earthworms 
tested are listed if this information was included in the original 
paper. Treatment rates are expressed as actual amount of chemical per 
unit area, not as the amount of formulated mixture. 
BOTANICALS 
Mowrah Meal 
Mowrah meal, a product of the Indian tree bean of the genus 
Lllipe, has been used as an earthworm expellent. Bingley (1949) reported 
its effectiveness, but noted that the cost was high. He gave no further 
details. 
The author is now with the U.S. Bureau of Commercial Fisheries at St. Paul 
Island, Alaska. 
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