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

S. macrophylla and Swietenia mahagoni Jacq.
have been grown in small areas in mixed species
plantings and have both been severely attacked by H.
robusta with S. mahagoni being more severely
attacked. S. macrophylla is not always severely
attacked but the circumstances leading to attack are
not well understood. Trees can also be severely
damaged by bark feeding squirrels. In nurseries,
weak seedlings may also be attacked by scolytid
borers and the collar borer, Pagiophloeus longiclavis
Marshall (Coleoptera: Curculionidae).
The native species of Toona, T. sinensis (A. Juss.)
M. Roem and T. sureni, have been established in
open plantings in urban areas or in mixed plantings
with each other. T. sinensis has grown quite well,
while T. sureni has suffered severe attack by
H. robusta.
Growth and Productivity of Swietenioideae
Species
Some growth data have been collected but no
economic analysis of plantation operations has been
performed.
The growth rate of S. macrophylla has been
described in brief accounts of trial plantations at
FRIM, Kepong (Barnard and Beveridge 1957;
Streets 1962; Ng and Tang 1974; Appanah and
Weinland 1993) while Hashim et al. (1989) compared
the growth rate at FRIM with that from other
parts of Peninsula Malaysia. In general, the early
growth is very variable and this is believed to be due
to soil factors. At 9 years, the mean annual increment
in diameter of selected dominant trees was 1.5 cm. A
24-year-old tree growing on a moist site in well
drained, sandy soil at FRIM had a height of 23.5 m,
clear bole height of 8.2 m and a diameter of 66 cm.
In Malacca, a 33-year-old tree under open conditions
on poor lateritic soil had a height of 25 m and a
diameter of 54 cm. S. macrophylla trees in Malaysia
rarely have straight clear boles longer than 9.2 m.
Brief data on growth rates for K. ivorensis are
given in Ng and Tang (1974), Darus et al. (1990),
Hashim (1990) and Appanah and Weinland (1993).
The mean annual increment in height was 1.0 m and
in diameter was 1.9 cm for a 26-year-old tree in
Kedah (Darus et al. 1974).
Noraini et al. (1994a, b) and Noraini and Hanim
(1996) made some studies on the establishment and
initial growth rates of some of the native Swietenioideae
(Toona spp. and C. tabularis) while Ng and
Tang (1974) reported a 33-year-old tree of
C. tabularis with a clear bole of 15.5 m and a
diameter of 58 cm.
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Hypsipyla robusta Research and Future
Directions
A summary of the extent of current and historical
research into H. robusta in Malaysia is presented in
Table 4. Overall, there has been very little previous
research conducted on H. robusta in Malaysia except
for reports on its attack and some attempts at
chemical or silvicultural control. Current research is
still at an early stage and mainly comprises preliminary
observations on the biology of the species.
Experimental trials on the management of H.
robusta have been delayed pending the establishment
of new plantings. Past reports on the attack of
H. robusta, as well as the current observations on the
extent of attack at different sites and on different
plant species, have provided an insight into the
biology and possible present occurrence of the pest.
These observations have helped to determine the
direction of future research and also to assess the
planting potential of some species of Swietenioideae.
Table 4. Summary of current and past research effort on
various aspects of Hypsipyla robusta biology and control.
Area of study Current
research
– none; * minor; ** major.
Historical
research
Biology
Taxonomy – –
Life history ** –
Ecology in natural stands – –
Ecology in plantations ** –
Population dynamics ** –
Natural enemies ** –
Other
Control
– –
Biological control ** –
Chemical control * *
Silvicultural control ** *
Host resistance * *
Pheromones ** –
Genetic engineering – –
Other – –
Swietenia mahagoni was introduced into Malaysia
in 1876 and S. macrophylla in 1886 and again in
1892 (Burkhill 1936). Both species were attacked by
H. robusta although the attack was more severe on
S. mahagoni, which is no longer being planted
except for comparative experimental trials.
Some good specimens of S. macrophylla established
in these early plantings have survived as
ornamentals in the larger towns and also as a small
group of plantings in Bukit Bruang Forest Reserve in