Pest Problems Abroad May Affect Compliance With
U.S. Safeguards
Michael
Livingston
![Photo: Medfly on fruit](https://webarchive.library.unt.edu/eot2008/20080920193340im_/http://www.ers.usda.gov/AmberWaves/June08/Findings/Photos/findings_re1.jpg)
Ninety-five percent of Mediterranean fruit
fly (medfly) outbreaks in the continental United
States since 1929 have occurred in Florida and California.
USDA, along with California’s and Florida’s
departments of agriculture, use preventive release
programs to reduce the severity and frequency of
outbreaks. Millions of sterile male fruit flies
are released weekly where outbreaks have occurred.
If a wild, fertile female medfly is nearby, she
is likely to mate with a sterile male medfly, produce
eggs that do not hatch, and be unable to mate again.
Medflies are known to exist in
65 countries that export fresh produce to the United
States. Because female medflies lay their eggs inside
the produce, USDA regulates fresh produce importation
to reduce the rate of new invasions. Among the approved
and commonly applied ways to eliminate medfly larvae
is cold treatment: refrigeration at a mandatory
average temperature for a specific time period.
Live medflies were confirmed in
separate shipments of clementines from Spain in
2001, prompting USDA to amend regulations governing
their importation and the cold treatment of fresh
produce from all known medfly regions. Subsequent
analysis by USDA’s Animal and Plant Health
Inspection Service suggested that the specified
duration of treatment may not have achieved satisfactory
control; therefore, USDA extended the required length
of the treatment time.
Using a simulation model, ERS examined
treatment schedules that maximize U.S. produce consumers’
and producers’ net benefits from efforts to
control fruit fly outbreaks. In the model, a representative
foreign producer exports a fraction of production
to the United States and the remainder to the rest
of the world, and implements medfly controls to
maximize profit. If medflies survive pesticide sprays
and cold treatment abroad, as well as the domestic
preventive release program, an outbreak causes domestic
yield losses and production cost increases in the
U.S.
The results of the analysis show
that the economically optimal number of days to
treat imports increases with the severity of medfly
outbreaks abroad. The optimal treatment schedules
are very similar to current treatment schedules.
The treatment period that maximizes foreign producer
profit also varies with the severity of outbreaks.
When local infestations are at or below average,
the results suggest that economic incentives abroad
are consistent with U.S. policy. However, when local
infestations are above average, foreign producers
have an economic incentive to treat their produce
below the U.S. optimal level. This occurs because
yield losses and control costs increase with the
severity of outbreaks to the point where profit
is maximized at a treatment level lower than the
U.S. optimal level. The disparity between U.S. goals
and foreign producers’ incentives shows the
importance of monitoring compliance with cold treatment
regulations and provides justification for USDA’s
practice of doing so.
Optimal
cold treatment schedules for medfly infestations
may differ from
treatments designed to maximize foreign producers’
profits
|
Medfly
outbreak
severity abroad
|
Optimal treatment
for United States
|
Optimal treatment
for representative
foreign producer |
|
Days
|
|
Days |
|
Below
average |
8 |
32.5 |
9 |
32.5 |
Average |
11 |
32.5 |
11 |
|
Above average |
12 |
33.0 |
11 |
32.5 |
Source: Livingston, M. J.
“The Mediterranean Fruit Fly and the
United States: Is the Probit 9 Level of Quarantine
Security Efficient?” Canadian Journal
of Agricultural Economics, 55 (2007):515–526.
|
This
finding is drawn from . . . |
“The
Mediterranean Fruit Fly and the United States:
Is the Probit 9 Level of Quarantine Security
Efficient?” by Michael Livingston, in
Canadian Journal of Agricultural Economics,
55(2007):515-526.
|
|