July 25, 1997. Copyright, 1997, Graphic News. All rights reserved

Sex war declared on fruit flies

FloridaÕs agriculture officials are planning to release 300 
million sterile male fruit flies in a last-ditch attempt to 
eradicate a nine-week infestation of medfly which threatens the 
stateÕs $6 billion agricultural industry.

The current infestation began when a state inspector found a 
solitary Mediterranean fruit fly on May 28 in the back garden of 
a suburban house near Tampa, on Florida's Gulf coast.
The fly, known  to scientists as Ceratitis capitata, is one of 
the most destructive pests of over 200 species of fruits, nuts, 
and vegetables, especially citrus, mangoes, avocados and tomatoes 
Ð all of which grow throughout central and southern Florida. 

A single female can lay up to 800 eggs beneath the soft skin of 
the fruit or vegetable. The eggs hatch into larvae, drop to the 
ground and become cocoons. After eight days, they emerge as adult 
flies, ready to repeat the cycle.

The first U.S. medfly infestation occurred in grapefruit groves 
near Orlando in 1929; it spread to 20 counties throughout the 
state and took nearly two years and several million dollars to 
bring under control. Other outbreaks in 1956 and 1962 in Miami 
and the counties to the north were equally difficult to contain 
and even more costly.

An infestation can spread so quickly that the federal government 
now spends $15m each year just to hang fly traps in areas known 
to be attractive to medflies. It was in such a trap that the 
first culprit appeared.

Since early June the Agriculture Department have expanded a 
quarantine zone through central Florida to prevent the spread of 
the fly. Initially, specially modified DC-3 aircraft and 
helicopters, last seen in Vietnam, bombarded infested areas with 
the pesticide Malathion but this effort brought controversy. 

Citizens for Responsible Application of Malathion (CRAM) 
complained that the Agriculture Department Ð which had been 
banned from spraying the pesticide within 200 metres of lakes and 
rivers Ð was polluting their waterways.

CRAM, joined by Hillsborough County Commissioner Joe Chillura, 
wants the spraying replaced with alternative eradication methods.

ÔThe public cannot understand how Malathion is not harmful when 
it is capable of damaging the paint on your car from just one 
overfly,Õ Chillura said in a statement last week.

In response, the medfly-fighters will stop attacking the insects 
with Malathion and will attack them with sex instead. They plan 
to release up to 300 million sterile male fruit flies into the 
quarantine zone each week. The sterile flies Ð raised in 
laboratories in Guatemala and rendered sterile with gamma rays Ð 
are expected to mate with females which will be unable to 
reproduce. Within a few weeks, it is hoped that they will mate 
themselves out of  existence.

/ENDS

Sources: Reuter, The Economist