Silent Spring by Rachel Carson

and having complete control over their material. Sometimes compressor pumps and material
can be mounted on truck chas s is , but there is no blanket s praying. Treatment is directed only to
trees and any exceptionally tall s hrubs that mus t be eliminated. T he integrity of the
environme nt is thereby pres erve d, the enormous value of the wildlife habitat remains intact,
and the beauty of s hrub and fern and wildflowe r has not been sacrificed. Here and the re the
method of vegetation management by s elective s praying has been adopte d. For the mos t part,
entre nched cus tom dies hard and blanket s praying continues to thrive, to exact its heavy
annual cos ts from the taxpaye r, and to inflict its damage on the ecological web of life. It thrives,
s urely, only becaus e the facts are not known. W hen taxpayers unders tand tha t the bill for
s praying the town roads s hould come due only once a generation ins tead of once a year, they
will s urely ris e up and demand a change of method.
Among the many advantages of selective spraying is the fact that it minimizes the amount of
chemical applied to the lands cape. There is no broadcasting of material but, rather,
concentrated application to the bas e of the trees. The potential harm to wildlife is therefore
kept t o a mi ni mu m. The mos t widely us ed herbicides are 2,4-D, 2,4,5-T, and related
compounds. Whether or not these are actually toxic is a matter of controversy. People spraying
their lawns with 2,4-D and becoming wet with spray have occasionally developed severe
neuritis and even paralys is. Although s uch incidents are appare ntly uncommon, me dical
authorities advis e caution in us e of s uch compounds. Other hazards , more obs cure, may als o
attend the ris e of 2,4-D. It has been s hown expe rime ntally to dis turb the bas ic phys iological
process of respiration in the cell, and to imitate X-rays in damaging the chromos omes. Some
very recent work indicates that re producti on of birds may be advers ely affected by thes e and
certain other herbicides at levels far below those that cause death. Apart from any directly toxic
effects , curious indirect res ults follow the us e of certain herbicides. It has been found that
animals, both wild herbivores and livestock, are sometimes strangely attracted to a plant that
has been s prayed, even though it is not one of their natural foods. If a highly pois onous
herbicide s uch as ars enic has been us ed, this intens e desire to reach the wilting vegetation
inevitably has disastrous results. Fatal results may follow, also, from less toxic herbicides if the
plant its elf happens to be pois onous or perhaps to pos s es s thorns or burs. Pois onous range
weeds, for example, have s uddenly become attractive to lives tock after s praying, and the
animals have died from indulging this unnatural appetite. The literature of veterinary medicine
abounds in similar examples: swine eating sprayed cockleburs with cons equent severe illness,
lambs eating s prayed this tles , bees pois oned by pas turing on mus tard s prayed after it came
into bloom. Wild cherry, the leaves of which are highly poisonous, has exerted a fatal attraction
for cattle once its foliage has been s prayed with 2,4-D. Apparently the wilting that follows
spraying (or cutting) makes the plant attractive. Ragwort has provide d othe r examples.
Livestock ordinarily avoid this plant unless forced to turn to it in late winter and early s pring by
lack of other forage. However, the animals eagerly feed on it after its foliage has been sprayed
with 2,4-D. The explanation of this peculiar behavior sometimes appears to lie in the changes
which the chemical brings about in the metabolism of the plant itself. There is temporarily a
marke d increas e in s ugar content, making the plant more attractive to many animals.
Another curious effect of 2,4-D has important effects for livestock, wildlife, and apparently for
men as well. Experiments carried out about a decade ago s howed that after treatme nt with this
chemical there is a sharp increase in the nitrate conte nt of corn and of s ugar beets. The s ame