Biology Reference
In-Depth Information
13.7.4 Eradicating Medflies in California?
The Mediterranean fruit fly (Medlfy),
Ceratitis capitata
, is an immensely destruc-
tive pest of agriculture. It is a native of sub-Saharan Africa, but invaded the
Mediterranean basin, portions of Central and South America, Hawaii, and
Australia during the past 100-200 years.
Ceratitis capitata
is able to feed on
>
200 host plants and can survive in a variety of climates (USDA-APHIS 2002).
Females deposit up to 1000 eggs in fruits (including peaches, pears, plums,
apples, apricots, avocados, citrus, cherries, figs, grapes, guavas, kumquats,
loquats, nectarines) or vegetables (peppers, tomatoes), and the resulting mag-
gots eat the fruits or vegetables, leaving them mushy and infested with mold.
Medflies can develop from egg to adult in 21 days, so populations can increase
exponentially in favorable climates.
Ceratitis capitata
is a quarantined pest, meaning that when it is detected
in the United States efforts are made to eradicate it (USDA-APHIS 2002).
Eradication efforts are justified because this pest significantly increases crop-
production costs; pesticide applications to suppress Medfly can disrupt biological
control of other crop pests; and fruits grown in Medfly-infested regions cannot
be exported to Medfly-free areas, thereby affecting national and international
trade. Furthermore, establishment of Medfly would create serious pest problems
in backyard gardens and orchards.
Eradication efforts involve surveys, regulation, and control. Surveys con-
ducted by the USDA-APHIS and the States involve placing Medfly traps in high-
risk areas, especially near international airports and seaports. If an infestation
is found, additional traps are placed to determine the extent of the infestation;
unfortunately, the traps are not 100% efficient and very low populations can be
missed. Control methods include application of aerial and ground bait sprays,
release of large numbers of sterile flies (sterile insect release method [SIRM]),
and application of pesticides to the soil under infested trees to kill larvae as they
enter the soil to pupate and the adults as they later leave the soil. Movement
of host plants out of the infested area is prohibited and, in some cases, infested
fruits may be picked and destroyed.
13.7.4.1 The Controversy
Since 1975, California has grappled with a controversial problem. The periodic
and repeated appearance of Medflies in traps, especially in the Los Angeles
basin, has raised questions as to whether California can export agricultural
products as a “Medfly-free state” and whether the eradication efforts have
been successful (
Carey 1991, Abate 1993, Carey 1996a,b, Myers et al. 2000
). This
