Ecological Side Effects Of Pesticide
And Fertilizer Use On Turfgrass
Understanding
these effects
can aid the development
of new products
and turf management
programs
that get the job done
with minimum
disruption
to natural processes.
Daniel A. Potter
Department
of Entomology
University of Kentucky
Recent growth of the turfgrass indus-
try has resulted in an increasing number
of golf courses,
lawns and other
turf
areas being maintained with repeated
applications of pesticides and fertilizers.
Pesticides are indispensable
tools of the
modern turf manager, but their use can
sometimes have undesirable side effects
on beneficial organisms and on impor-
tant processes such as thatch decompo-
sition and natural
regulation
of pest
populations.
Research
is under way to
clarify how chemical applications affect
these processes.
Numerous
kinds of predators
and
parasites are abundant
in turfgrass.
In
Kentucky, more
than 30 species
of
spiders,
42 species of ground beetles
(Carabidae) and 40 species of rove bee-
tles (Staphylinidae) were represented
in
pitfall trap samples from urban turf areas
(Cockfield
and Potter
1985).
These
creatures
appear
to be important
in
maintaining
pests
at non-damaging
levels. For example,
in one field experi-
ment (Cockfield and Potter 1984) it was
found that predators
consumed
up to
75 percent of a cohort of sod webworm
eggs within 48 hours. Natural enemies
that help to limit percent populations of
turfgrass pests include parasitic wasps,
nematodes,
spiders,
ants and beetles.
When
insecticides
are applied
for
control of pests,
they also affect benefi-
cial species. For example,
one surface
application
of insecticide may reduce
predator populations by 60 percent for
up to six weeks (Cockfield and Potter
1983). There is evidence
that pest out-
breaks on treated lawns are sometimes
related to interference with natural con-
trol agents
(Streu and Gingrich 1972,
Reinert 1978, Potter 1982). Research
Continued
Golf Course Management
/ October 1987
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