96 
Psyche 
[June-September 
An auxiliary control used in heavily infested zones was the applica- 
tion of a formulation at the rate of five pounds of dieldrin per acre 
to the soil under infested trees. This was aimed at pupating larvae 
and adults leaving the pupal stage. 
The program progressed steadily. Infestations were found in a 
total of 28 counties, most of them south of the 1929 zone. While the 
1929 infestation had affected mainly the major commercial citrus 
groves of central Florida, the 1956 invasion was centered more in 
the ornamental and dooryard plantings of residential areas in the 
southern part of the state. This required the use of more of the 
safer twin- and four-engined planes in the low altitude bait-application 
flights. 
One year after the first discovery of 1956, nine-tenths of the total 
acreage had been treated, and only about 1 2,000 acres of new infesta- 
tions remained to be discovered. One by one, during late 1956 and 
early 1957, counties were released from the aerial spraying routine 
after no more flies could be found in them, and in November, 1957, 
the last known infestation was eliminated from an island off the coast 
in Manatee County. The cost of the eradication program, paid jointly 
by the state and Federal governments, was about $1 1 million, but only 
small quantities of fruit had had to be stripped from the trees and 
destroyed. 
Eight hundred thousand acres were sprayed one or more times — 
some of them up to a dozen times — for a total of six and one-half 
million spray-acres. Twelve million pounds of malathion and a million 
gallons of sauce base went into the bait spray, and 1,667,217 pounds of 
dieldrin were used in the bait treatment, A maximum of 800 person- 
nel was involved in the 1956 struggle, as compared to the 6,000 of 
the 1929 campaign — labor costs of course having; risen steeply since 
the earlier campaign. At the peak of the campaign, some 54,000 
detection traps were in use all over Florida, and additional trapping 
was done in other southern states and Cuba in areas where preferred 
host fruits grow. About 12,000 fly 1 specimens were caught, and none 
of these came from states outside Florida. The Florida Legislature 
has voted funds for continued lure trapping, using combined lures 
for several fruit fly species in addition to the medfly. In June, 1958, 
32,000 traps were still in use throughout Florida. 
Harmful Effects of the Campaign 
It seems reasonably clear that the two medfly campaigns were com- 
pleted with little serious loss of wildlife or damage to non-infested 
crops, domestic animals and human property. The 1956 program 
