Introduction. In the water-saving
and income-generating agroforestry cropping systems developed and
promoted by the ICRISAT in the Sudano-Sahelian zone of West Africa, particularly
in Niger, fruits of domesticated Ziziphus mauritiana (“apples
of the Sahel”) are severely damaged by fruit flies (Carpomya incompleta),
and chemical pesticide application poses economic, environmental
and human health problems. In the Bio-reclamation of Degraded Lands (BDL)
system, apple of the Sahel is the main high-value crop, while in
the Dryland Eco-Farm (DEF), it is grown alongside watermelon. Sclerocarya
birrea (marula plum) is presently being investigated as
a dryland tree species for fruit and oil production, either in orchards
or such systems as BDL. Materials and methods. To complete
preliminary results of earlier studies published elsewhere, we collected
and incubated in 2010 ripe fruits of marula plum and watermelon
in Sadoré, Niger, where the above-mentioned agroforestry systems
are developed, and we recorded emerging fruit flies. We also conducted
a spot-spraying experiment (using GF-120) in an apple of the Sahel orchard
in Niamey in 2010; we recorded undamaged and damaged fruits and incubated
the latter. In the same orchard, we set up in 2011 a fruit fly trapping
survey targeting the invasive species Bactrocera invadens (Chempac®
traps using methyl eugenol as the attractant). Results and discussion.
The results showed that only Ceratitis cosyra emerged
from marula plums, and only Dacus spp. from watermelon.
The GF-120 spot-spraying experiment showed that C. incompleta was not
attracted / intoxicated, contrary to Ceratitis spp.
and Dacus spp.; the sprayed trees yielded significantly more
marketable fruits than unsprayed ones; only C. incompleta emerged
from damaged fruit. Detection trapping revealed for the first time
the presence of B. invadens in the Sahelian zone of
Niger, including at the time of apple of the Sahel fruit production.
Conclusion. This, alongside results of earlier studies,
suggests a repellent effect of GF-120 on the monophagous C. incompleta species
(Trypetinae), while it is attractive to oligophagous/polyphagous
Dacinae fruit flies; some of them (e.g., Dacus spp.)
damage watermelon, which is part of the DEF system, and produce
fruit at the same time as the jujube tree. The prospects for harnessing
these two opposite regulation pathways are discussed.