Malathion spraying
The Event An insecticide is widely used on crops
and released over populated areas
Date July, 1981
Though used since the 1950’s and considered safe, mala-
thion’s application by aerial spraying over a large popu-
lated area of California to kill Mediterranean fruit flies cre-
ated public furor.
A neurotoxin, malathion is an organophosphate in-
secticide. Because mammalian liver enzymes neu-
tralize malathion and because it degrades quickly in
the environment, it is considered to be the least
harmful organophosphate. Used in both ground
and aerial spraying, it controls crop pests such as the
Mediterranean fruit fly (Medfly), aphid, and cotton
boll weevil, as well as home garden pests. Before the
1980’s, malathion was widely used, notably on citrus
crops in Florida.
Medflies infest more that two hundred different
crops and have the potential to cause great eco-
nomic damage. In June, 1980, a male Medfly was
found in a trap in California. By July, a commis-
sion had quarantined large areas in Los Angeles
and Santa Clara counties. When
the release of sterile male Medflies
failed to curb the infestation,
the U.S. Department of Agricul-
ture proposed spraying with mala-
thion. Fearing adverse effects on
public health, some county offi-
cials voted to ban the spraying.
This action spurred the Califor-
nia State Department of Health
Services to survey literature on
the effects of malathion on hu-
man health. When the depart-
ment found little evidence of
harm to humans, ground spray-
ing commenced.
However, in June, 1981, Medfly
larvae, which eat the fruit, were
discovered. Sensitive to the de-
mands of environmentalists, Gov-
ernor Jerry Brown opposed the
recommendation for aerial spray-
ing of both agricultural and in-
habited areas. When the federal
government threatened to quar-
antine California produce, a threat to the $14 billion
industry and to U.S. food prices in general, the gov-
ernor changed his mind. Officials argued that the
economic benefits far outweighed any possible risks
to humans. They pointed out that because mala-
thion was mixed with sugar and molasses in the ae-
rial spray, it was difficult to inhale, and the director
of the California Conservation Corps publicly drank
a small quantity of very dilute malathion to demon-
strate its safety. Aerial spraying of 1,400 square miles
began in mid-July. During the spraying, residents fol-
lowed simple rules, such as remaining indoors dur-
ing the actual spraying, closing windows, removing
toys and household articles from yards, and covering
cars with sheeting. Few went to Red Cross shelters
established as refuges. In the summer of 1982, the
Medflies were discovered in the fruit-growing re-
gions and malathion spraying commenced immedi-
ately.Impact In September, 1982, officials announced
that the Medfly had been eradicated. Spraying with
malathion continued off and on in California and
Florida for the rest of the decade. Studies of children
born to women pregnant during the spraying foundThe Eighties in America Malathion spraying 615
The Mediterranean fruit fly, or Medfly, is a worldwide agricultural pest. In 1981, Cali-
fornia governor Jerry Brown ordered the spraying of malathion insecticide to combat
Medfly infestation.(USDA/Scott Bauer)