Pest Management in Miombo Fruit Trees - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 387

pests and a large number of occasional pests of local importance. Armillaria ,
Colletotrichum gloeosporioides and termites may be considered as priority
pests since they affect a wide range of fruit trees. Considering the direct
damage they cause and their quarantine status, fruit-feeding insects, especially
Ceratitis spp. and C. leucotreta , also seem to be key pests that merit significant
research and development efforts in most of the miombo fruit tree species.
Until recently, the conservation and tending of miombo fruit trees in the
natural forest has been traditionally encouraged. Thus, IPM measures to
combat pests have been argued to be uneconomical and impractical in the
natural forest (Parker, 1978). In the natural forest the pests are components
with roles in the forest succession and they make up a substantial part of the
biodiversity, and pest damage may not be obvious because of the balancing
effect of this biodiversity. However, problems are likely to increase as fruit trees
are grown extensively in a new environment under managed conditions. IPM
may become necessary when nurseries and orchards of improved fruit tree
varieties become established for the commercial utilization of fruits. It is clear
from the foregoing discussion that IPM cannot be developed for individual
pests or tree species. It is also clear that IPM should be an integral component
of good agricultural practices. Such practices should be farmer-driven and user-
friendly. Many factors influence the priority given by farmers to tree health
problems and hence the locally expressed demand for pest management
research and development. Among the major factors is the lack of knowledge
of tree ill-health and poor diagnosis, which also results from lack of diagnostic
tools. Hence, pest attack may be confused with nutrient deficiencies or the
unspecified problems most often referred to as 'poor site condition'.
Farmers' perceptions of the definition of tree pests depend on the
economic value that they attach to a tree, the part of the plant attacked and the
amount of damage caused. For instance, the edible caterpillars Cirina forda ,
Gynanisa maja , Gonimbrasia zambesina , Gonimbrasia belina and Micragone
cana may seriously defoliate miombo fruit trees. In Zambia the caterpillars are
considered as pests by foresters because of the defoliation and the damage
done by people collecting them. However, farmers tolerate them because they
consider them an essential source of protein food (Mughogo and Munthali,
1995; Mbata et al ., 2002). Local communities are knowledgeable about edible
caterpillars and often make an effort to conserve them (Mbata et al ., 2002).
Trees such as Uapaca kirkiana are hosts for the bug Encosternum delegoruri
and various caterpillars that are eaten by communities in Malawi and
Zimbabwe (Makuku, 1993; Meke, 1998; Mbata et al ., 2002). Miombo fruit
trees can also host wild silkworms, such as Argema mimosae and Gonometa
species. Adoption of policies and practices that encourage the integration of
nutritionally important edible insects with the cultivation of wild fruit-bearing
trees will significantly benefit poor communities living in marginal agricultural
areas and will also increase the adoption of these trees.