Introduction. Losses in West African commercial
mango orchards due to fruit fly infestations have exceeded 50% by
the middle of the crop season since 2005, resulting in considerable
income loss for the growers. Materials and methods.
In 2009, weekly monitoring of adult fruit fly species of economic
significance was carried out in eight West African countries at
12 sites across five agro-ecological zones: (i) Humid Forest, (ii)
Guinean savanna, (iii) Southern Sudan, (iv) Northern Sudan, and (v)
Sahelian. Trapping was performed using methyl eugenol and terpinyl
acetate in 288 Tephri-traps, targeting Bactrocera invadens and
Ceratitis cosyra. Results. The data
showed that B. invadens was present throughout
the year in the Forest zone, abundant for 7 months, with a peak
in May at the end of the mango season, C. cosyra being
totally absent. In the Guinean savanna zone, B. invadens was
abundant for 6-7 months, with a peak at the beginning of June coinciding
with the season, with a few C. cosyra. In the Southern
Sudan zone, B. invadens was abundant for 6 months, with
a peak in mid-June during the season, C. cosyra peaking
in April. In the Northern Sudan zone, B. invadens was
abundant for 5 months, with a peak at the end of June at the end
of the season, C. cosyra peaking in May. In the
Sahelian zone, B. invadens was abundant for 4 months,
peaking in August during the season, C. cosyra peaking
just before. These preliminary results showed that the exotic species,
B. invadens, was present at high levels [mean peak
of 378 flies per trap per day (FTD)] in all agro-ecological zones, while
the native species, C. cosyra, preferred the drier
zones of West Africa, with lower population levels (mean peak of 77 FTD).
Conclusion. Detection trapping of male flies with parapheromones
is a useful indicator of field population levels and could be used
to deploy control measures (IPM package) in a timely manner when
the Economic Injury Level is reached. Control strategies for these
quarantine mango fruit fly species are discussed with respect to
agro-ecological zones and the phenological stages of the mango tree.