Hypsipyla Shoot Borers of Meliaceae in Sri Lanka - Australian ...

Table 2. Native and exotic tree species of Meliaceae subfamily Swieteniodeae planted in Ghana (Forest Products Research
Institute, Ghana, Annual Reports 1969–1979).
Tree species Origin Present area planted
(ha)
excessive shade, while the Taungya system restricted
the farmers’ choice of crops and gave the farmers no
stake in the trees, as a result of which tending
operations were not well executed. Other reasons for
plantation failures include fire, poor seed sources,
poor species-site matching, inappropriate choice of
species, and pests and diseases.
The main plantation species that have been grown
with some success are exotics such as Tectona
grandis L., C. odorata and Gmelina arborea Roxb.
(Table 3). Overall establishment success of all
species was generally poor, however they were
particularly so for native Meliaceae, of which only 9
per cent survived.
Table 3. Principal tree species in plantations and survival
rate in Ghana (Forestry Department, Planning Branch 1992).
Tree species Area planted
(ha)
Survival
(%)
Tectona grandis L. 25 800 34
Cedrela odorata L. 7 900 39
Gmelina arborea Roxb. 6 500 58
Mansonia ultissima A. Chev. 3 000 22
Native Meliaceae 2 400 9
Triplochiton scleroxylon K. Schum 100 20
Terminalia ivorensis A. Chev. 150 27
Eucalyptus spp. 2 000 n/a
Although the poor establishment of all species in
Ghana was largely due to fire, the particularly high
failure-rate of plantations of native Meliaceae has
been attributed to shoot borer attack (Ofosu-Asiedu,
et al. 1991). Shoot borer also resulted in slow growth
and poor form (Britwum 1976). Similarly, planting
of the exotic Swietenia spp. has been discontinued
due to poor fire tolerance and serious shoot borer
attack: the trials invariably failed through die-back
resulting from shoot borer attack and fire (Ofosu-
Asiedu, et al. 1991).
Roberts (1966) lists native and exotic Meliaceae
that are susceptible to H. robusta in West Africa.
The only member of the sub-family Swieteniodeae
60
Present planting rate
(ha/Year)
of which there is no record of attack by the shoot
borer in Ghana is the exotic C. odorata, which is one
of the most successful plantation species (Table 3).
In Ghana, C. odorata is a fast growing tree and at
Pra-Anum, which is in the moist semi-deciduous
forest zone with an annual rainfall of 1200–1800
mm, sample plots in a 20-year old plantation had an
average height of 39.9 m (Nkansa-Kyere 1974). No
pests or diseases of importance have ever been
reported on C. odorata although the plant is susceptible
to attack by ambrosia beetle Doliopygus condradti
Strohm. (Platypodidae), especially during
long, dry periods (Wagner et al. 1991).
Recently, the Forestry Department has recognised
the increasing interest of individual farmers and
community associations in plantation establishment
and is promoting woodlot establishment on private
land and farms through the Collaborative Forest
Management Unit. In addition, several private companies
have embarked on large-scale, commercial
planting of exotic species outside the Forest Reserve.
However, efforts by foresters to plant indigenous
Meliaceae and Swietenia species in the various
countries of West Africa have been frustrated by H.
robusta damage and there are currently no plans by
the Forestry Department to plant these species in
plantations (Table 2). Only one company, the Swiss
Lumber Company in the southwest region, has
recently invested in planting indigenous Meliaceae.
Hypsipyla Research in Ghana
Optimal rotation
length (yrs)
K. ivorensis A. Chev. Native 2400 Planting ceased in forest reserves Not known
E. utile (Dawe & Sprague) Sprague Native 2400 Planting ceased in forest reserves Not known
E. cylindricum (Sprague) Native 2400 Planting ceased in forest reserves Not known
E. angolense (Welw.) DC Native 2400 Planting ceased in forest reserves Not known
Cedrela odorata L. Introduced 7900 50 About 40 yrs
Swietenia humilis Zucc. Introduced 0 Planting ceased n/a
S. macrophylla King Introduced 0 Planting ceased n/a
The research into H. robusta in Ghana is summarised
in Table 4. The Forestry Research Institute of Ghana
(FORIG) have successfully reared H. robusta on an
artificial diet and described the stages of the life
cycle (Atuahene and Souto 1983). The medium used
was the McMorran Grisdale Diet (MGD) generously
supplied by Prof. G.I. Gara of the College of Forest
Resources, University of Washington, USA. The
results revealed differences in the life cycle of H.
robusta from those reported in Nigeria (Roberts
1966) and Ivory Coast (Couillard and Guiol 1980).