2020

Animal & Plant Health Inspection Service

Cooperative Fruit Fly Emergency Response Triggers & Guidelines

Emergency Response Triggersi

Delimitation Duration of 

Delimitationii

(# generations 

for single fly 

detections)

Eradicationiii Quarantineiv

Mated female of any genus and species of 

fruit fly presumed or known to be mated 

to a wild malev; a larva or pupa

1 mated female 

or immature

stage

F3 1 mated female 

or immature

stage

1 mated female or 

immature stage

Ceratitis capitata (Medfly) and other 

species within the genus Ceratitis

1 fly F3 2 flies within a 

3 mile (4.8 km)

radius during 1

life cycle

2 flies within a 3-mile

(4.8 km) radius during 

1 life cycle

Bactrocera dorsalis (Oriental FF)

Other Bactrocera species responding to 

methyl eugenol (ME): B. zonata (Peach FF), 

B. correcta (Guava FF), etc.

1 fly F2 2 flies within a 

3 mile (4.8 km)

radius during 1 

life cycle

If ALL finds are >4.5 

miles (7.2 km) from 

commercial host 

production area: 8 flies 

(either sex) within a 3-

mile (4.8 km) radius 

during 1 life cycle. 

If any find is <4.5 miles 

(7.2 km) from 

commercial host 

production area: 6 

flies within a 3-mile 

(4.8 km) radius during 

1 life cycle.

Other Bactrocera species that do not 

respond to methyl eugenol: B. latifrons, 

(Solanum FF), B. albistrigata (whitestriped FF), etc.

Zeugodacus cucurbitae (melon fly)

1 fly F3 2 flies within a 

3 mile (4.8 km)

radius during 1 

life cycle

2 flies within a 3-mile

(4.8 km) radius during 

1 life cycle

Anastrepha ludens (Mexfly) 1 fly F2 2 flies within a

3 mile (4.8 km)

radius during 1

life cycle

5 flies within a 3-mile

(4.8 km) radius during 

1 life cycle

Other Anastrepha species: A. serpentina 

(Sapote FF), A. obliqua (West Indian FF), 

A. fraterculus (South American FF), etc.

1 fly F3 2 flies within a 

3 mile (4.8 km)

radius during 1 

life cycle

2-5 flies within a 3-

mile (4.8 km) radius 

during 1 life cycle; if 

an Anastrepha 

species is not a 

regulated pest in the 

detection area, it 

may not require 

quarantine 

United States Department of Agriculture
2020

Emergency Response Triggersi

Delimitation Duration of 

Delimitationii

(# generations 

for single fly 

detections)

Eradicationiii Quarantineiv

Rhagoletis cerasi (European cherry FF) 1 fly F1 2 flies within a 

3-mile (4.8 km) 

radius during 

life cycle

2 flies within a 3-mile 

(4.8 km) radius 

during life cycle. 

Given the short 

cherry season in 

some regions, 

preemptive ECFF 

quarantines can be 

established if a 

spread model and 

delimitation trapping 

indicate that ECFF is 

likely to reach 

quarantine triggers in 

the following growing 

season. 

All other adult exotic fruit flies detected 

in the United States

1 fly F3 2 flies within a 

3 mile (4.8 km)

radius during 1 

life cycle

2 flies within a 3-mile

(4.8 km) radius during 

1 life cycle

All fruit fly triggers are subject to reassessment by the Fruit Fly Exclusion and Detection Cross Functional Working Group. 

(Revised December 4, 2020)

i

 In several regions of the United States, USDA APHIS PPQ and state cooperators engage in year-round or seasonal detection trapping 

for exotic fruit flies. Detection trapping densities should be replaced with delimitation trapping when emergency responses are 

triggered according to the criteria in this table. Consult regional fruit fly action plans for species- and region-specific operational 

requirements.

ii

 If no additional flies are found during the requisite number of generations, then the individual fly collected is presumed to have been 

transient and not to have reproduced. The more attractive the lure that is available for the fruit fly, the fewer generations are 

necessary for delimitation.

iii Eradication is initiated prior to reaching a federal quarantine.

iv Triggers for establishment of a new quarantine and expansion of an existing quarantine are the same. In other words, non-trigger 

detections adjacent to a quarantine would not trigger expansion of the quarantine.

v If a mated wild female is captured within an existing Sterile Insect Technique Preventative Release Program (SIT PRP) then an

evaluation takes place by program management or Cross Functional Working Group (CFWG) to assess the likelihood of a fertile to 

fertile mating. The assessment will consider the overall effectiveness of the PRP that has been ongoing in the area and pattern of 

sterile captures (fly/trap/day or FTD) in the area.