6 ILGINOTS ,AUDUBONA BUG at 
there obtain its adapted enemies, 
transship them to the invaded 
area, and colonize them in hope 
that they will become established, 
thrive, and subjugate their vic- 
tims. 
When the technique has been 
completely successful, it has pro- 
vided permanent control of the 
target species. In other words, the 
pests have been returned, more or 
less, to their earlier state of nat- 
ural balance. 
But there have been relatively 
few cases of complete success in 
classical biological control. It 1s 
estimated that only about one out 
of ten colonized species becomes 
established, and but a fraction of 
these ever attain any degree of 
significance. 
There are several reasons for 
this, but in considerable measure 
it is due to inefhciency and indif- 
ference on the part of those at- 
tempting establishment of the 1m- 
ported species. [This means that 
the degree of success in classical 
biological control might well be 
substantially increased and _ pro- 
duce enormous benefit. 
Economic Benefits 
It has been estimated that in 
California alone, between 1923 
(when the University of Califor- 
nia undertook biological control 
investigations) and 1959, the 
economic benefits to the state’s 
agricultural industry from natural 
enemy introductions amounted to 
approximately $115 million, at 
a cost of about $4.3 million. 
When the spotted alfalfa aphid 
reached peak destructiveness in 
California in the 1950s, hundreds 
of thousands of acres of alfalfa 
received multiple treatment of or- 
gano-phosphate insecticides, most- 
ly the highly dangerous parathion. 
Furthermore, the aphid became 
resistant to the chemicals and this, 
along with the elimination of nat- 
ural enemies by the insecticides, 
led to an insect nightmare in 
altalear 
But then introduced parasites, 
the better manipulation of native 
predators, and development of a 
highly selective control chemical 
greatly reduced the aphid prob- 
lem, so that between 1955 and 
1958 its costs to the alfalfa indus- 
try dropped approximately $13 
million per year to about $1.7 
million. A drastically reduced level 
of economic loss prevailed for sey- 
eral years thereafter until aphid 
resistant alfalfa varieties essen- 
tially eliminated the problem. 
Any analysis of the economic 
gains from classical biological con- 
trol is necessarily conservative be- 
cause it does not include ecologi- 
cal benefits. In other words, when 
a pest insect is brought under sub- 
stantial to complete biological 
control, the environment no long- 
er suffers massive inputs of the 
highly toxic and environmentally 
disruptive organophosphate — in- 
secticides. 
Thus it is quite apparent that 
the economic benefits from classi- 
cal biological control, gained at 
little expense have been enormous. 
Naturally Occurring 
Biological Control 
Literally everywhere on earth 
where chemical control of insects 
has been practiced during the past 
quarter century, there has been a 
resurgence of target pests and 
secondary pest eruptions in its 
wake. At times these have created 
economic disaster, as with cotton 
in South and Central America, 
