Tephritid fruit flies are serious economic pests worldwide. As larvae, they feed and develop within the
pulp of host fruits, making infestation difficult to detect by visual inspection. At U.S. ports of entry, incoming
produce shipments are checked for infestation by manually cutting open a small sample of fruit and
searching for tephritid larvae. Consequently, there is a need for more sensitive, high-throughput screening
methods. This study evaluated gas chromatography (GC) as a potential technology for improved
detection of hidden infestation. Grapefruits (Citrus×paradisi Macfad.) infested with immature stages of
the Caribbean fruit fly Anastrepha suspensa (Loew) (Diptera: Tephritidae) were examined to determine
if infested fruit emitted a chemical profile distinct from that of non-infested fruit. Peaks identified by
GC analysis were grouped into three classes. Chemicals detected in similar quantities in all samples, or
slightly elevated in infested samples, were regarded as non-diagnostic background volatiles. Chemicals
highly elevated after oviposition, during the last instar exit stage, and in experimentally-pierced fruit
were interpreted to be indicators of citrus peel injury, and included d-limonene and -ocimene. Chemicals
elevated exclusively in the larval infestation stages were considered indicators of feeding damage
and potentially diagnostic of infestation, and included hexyl butanoate and an unidentified compound.
The peaks associated with injury and feeding were also detectable with a portable ultra-fast GC analyzer
that required less than 80 s per sample. Further studies will investigate the potential application
of these results for development of a rapid, non-destructive screening method for detection of tephritid
infestation.