Contents - LAC Biosafety

Rwanda and Burundi) with 30 000 ha, India with 20 000 ha and Indonesia with
15 000 ha (CABI, 2005). It is also grown widely in subtropical parts of China.
For tannin production, it is usually grown in monoculture and managed on
8–10 years rotation.
Overview of pests
10.1 Acacia species (Fabaceae: Mimosoideae) 189
In Australia, where the species is native, a large number of insects are
associated with A. mearnsii. The leaf-eating chrysomelid beetle Acacicola orphana
(Erichson), commonly known as fire-blight beetle, is a serious pest in southern
Australia and Tasmania. Damage caused by this insect gives the plantation a
brown, scorched appearance (Elliott et al., 1998). The risk of A. orphana damage is
one of the major reasons why larger areas have not been planted with A. mearnsii
in southeastern Australia (Floyd et al., 1998). Other pests include a scarabaeid
beetle, Xylotrupes gideon, known as elephant beetle, which feeds on the bark
of branches of young trees, and larva of a cossid moth, Endoxyla liturata, which
bores into the wood and several species of sap sucking bugs (Elliott et al., 1998;
Floyd et al., 1998).
Over 200 species of insects have been recorded on exotic plantations of
A. mearnsii, some causing economic damage. Whitegrubs, termites, grasshoppers
and cutworms cause problems in the nursery. The bagworm Chaliopsis (Kotochalia)
junodi (Lepidoptera: Psychidae) is the most serious pest in South Africa. It causes
defoliation which affects the growth of the tree. Atkinson and Laborde (1996)
estimate that it infests 12 000–20 000 ha of wattle plantations annually in South
Africa; data for 42 years from 1953 to 1994 showed an average infestation of 25%
of the planted area. Chemical insecticides have been used for its control and 800
to 4000 ha have been sprayed annually. Trees up to two years old are also
attacked by a myrid bug Lygidolon laevigatum, which causes leaf lesion, leaf drop
and forking. It is estimated to affect about 2000 ha annually in South Africa
and insecticides have been used for its control (Atkinson and Laborde, 1996). This
insect is also rated as a serious pest in young plantations in Zimbabwe. In Kenya,
the lymantriids Argyrostagma niobe and Dasychira georgiana were reported to
defoliate A. mearnsii (Bullock and Smith, 1968). In southern Brazil, the beetles
Oncideres spp. (Coleoptera, Cerambycidae) cause heavy damage by girdling twigs
and branches (CABI, 2005). Also in Brazil, the geometrid Thyrinteina arnobia
sometimes causes complete defoliation of trees (Tarrago and Costa, 1990).
In China, more than 70 species of insects were recorded on A. mearnsii, which
included root-feeding termites, leaf-feeding caterpillars like Clania spp.
(Psychidae), Orgyia postica (Lymantriidae), Semiothisa spp. (Geometridae), Spirama
retorta (Noctuidae) and the sap-sucking scale insect Icerya purchasi (also recorded
in India). However, many pests are kept effectively under check by parasitoids