Pest Management in Miombo Fruit Trees - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 378

20 . 3.3 Flower- and fruit-damaging pests
Bacterial and fungal diseases
There is a dearth of information on bacteria affecting the reproductive parts of
miombo fruit trees. The only example is the bacterial spot caused by
Pseudocercospora purpurea , which affects Sclerocarya birrea fruits. Small
green spots appear on the fruit, which enlarges, breaks open, turns black and
gives off a gummy liquid (Hall et al ., 2002). The fungi that affect flowers of
miombo fruit trees are also little known. The well-known anthracnose fungus
Colletotrichum gloeosporioides affects the fruit of mango, avocado and papaya
(Ploetz et al ., 1994), Ziziphus spp., Parinari curatellifolia and probably S.
birrea . The fungus may disfigure the skin of 80% of P. curatellifolia fruits and
may cause pitted, irregular-shaped or distorted fruits. Scab, corking and raised
fissured areas result from infection of Uapaca kirkiana fruits (Parker, 1978).
Thus, the quality of wild fruits may be seriously reduced by this important and
widespread fungus. Other fruit-damaging fungi included rusts ( Puccinia sp.) on
fruits of Strychnos spinosa and S. madagascariensis , and Fusarium sp. affecting
fruits of Vangueria infausta in Mozambique.
Mites and insects
A variety of mites and insects, such as beetles, flies and caterpillars, are
involved in the destruction of blossoms, and, together with blight of the flower
stalk, are responsible for flower fall and fruit failure. For instance, mites damage
the flower buds of Sclerocarya birrea , causing flower malformation (Hall et al .,
2002). In southern Mozambique, the pyralid caterpillar Spatulipalpia monstrosa
and the nitidulid beetles Carpophilus spp. attack flowers and fruits of Annona
senegalensis and Vangueria infausta (R.R. Bandeira, unpublished results). In
Zambia and Zaire the main problem of Parinari curatellifolia is infestation of
immature fruits by larvae of the weevil Balaninus sp., which can cause up to
50% seed destruction and fruit fall (Parker, 1978). These could considerably
reduce the prospects of tree regeneration. Feeding by the thrips Heliothrips
haemorrhoidalis and Selenothrips rubrocinctus (Thysanoptera: Thripidae)
causes light brown blemishes on the skin of S. birrea fruits.
Carpophilus spp. bore into maturing fruits to feed on the sweet pulp of
most miombo fruit trees. C. hemipterus and C. fumatus attack Uapaca kirkiana ,
Sclerocarya birrea and Parinari curatellifolia fruits in Zambia (Parker, 1978; G.
Sileshi, unpublished results). In Malawi, C. fumatus attacks Ficus sycomorus
and other wild and cultivated fruits, while C. hemipterus attacks Adansonia
digitata , S. birrea and Morus alba (Lee, 1971).
The larvae of fruit flies and moths attack mainly mature or ripe fruits. Moth
larvae such as Deudorix sp., Cryptophlebia and fruit flies ( Ceratitis spp.) invade
the mature fruit pulp of Parinari curatellifolia (Parker, 1978). Sclerocarya birrea
is the primary natural host of the marula fruit fly Ceratitis cosyra , which can
infest its fruits heavily. The same fruit fly species is the major pest of mango in
Africa (Lux et al ., 1998, 2003). In addition, in Kenya, Tanzania and several
other countries, S. birrea is now heavily attacked by an additional fruit fly