A review of dipterocarps - Center for International Forestry Research

Pests and Diseases of Dipterocarpaceae 118
Philippines, Singapore, Thailand). It is a pest of
Parashorea robusta, P. malaanonan, P. stellata,
Shorea siamensis, S. assamica, S. obtusa, S. robusta,
Anisoptera glabra and Hopea odorata. This insect is a
principal pest in the Matang Forest Reserve of Sarawak,
Malaysia, and causes severe damage in central and
northern India on Shorea robusta. Outbreaks of this
insect have been recorded periodically since 1897 in
Chota Nagpur, India. The grub feeds on and destroys the
bast layer eventually killing the tree, and it tunnels down
into the heartwood spoiling it for commercial purposes.
This cerambycid has the habit of destroying the trees in
patches (Stebbing 1914). It produces characteristic
symptoms: i) dying-off from the crown downwards by
sudden withering of the foliage in autumn or spring; and
ii) profuse exudation of resin at points where the first
stage larvae bore through the bark.
The biology of H. spinicornis, the damage caused by
the insect and its control have been studied by Stebbing
(1914), Beeson and Chatterjee (1925), Atkinson (1926),
Beeson 1941, Bhasin and Roonwal 1954, Roonwal 1952,
1976, 1977, 1978, Mathur and Balwant Singh (1959,
1960a, b, 1961a, b), Mathur (1962), Chatterjee and Thapa
(1964, 1970), Sen-Sarma et al. (1974), Singh et al.
(1979), Mercer (1982), Singh and Mishra (1986),
Bhandari and Pratap-Singh (1988) and Baksha (1990).
The borers prefer large, mature trees, where there is more
chance of completing the life cycle. But during
epidemics this borer is capable of infesting every tree
above 0.3 m girth and and is not confined to mature or
over-mature trees. It then affects thousands of hectares
of Shorea robusta (Sen-Sarma and Thakur 1986). The
emergence of the adult beetle is closely synchronised
with rainfall (June/July). The beetles lay eggs in the bark
and sapwood and a heavily infested tree may contain as
many as 900 living larvae. Full grown larvae tunnel into
the heartwood and riddle it with galleries, making it unfit
for marketing as timber (Sen-Sarma and Thakur 1986).
Stebbing (1914) and Mathur (1962) described a method
of trapping the insect called the ‘tree-trap’ system. During
outbreaks, one tree per hectare is felled, and the log
beaten to expose the inner bark. The adults, attracted by
the inner bark, are collected by hand and destroyed. This
method has been used since then and is successful in
monitoring and controlling the beetle populations
(Chatterjee and Thapa 1970, Roonwal 1978, Bhandari
and Pratap-Singh 1988). A beetle can locate a freshly
felled tree of S. robusta at a maximum distance of 2 km
(Pratap-Singh and Misra 1981).
Many of the secondary borers attack freshly felled trees,
but can occasionally attack moribund trees and hasten
their death. They also attack young growth in sickly
condition due to some abiotic factors (frost or drought)
or biotic factors (e.g. infestation by defoliators) or kill
the trees (e.g. Massicus venustus) by mass-attack
(Beeson 1941). Most borers are not a threat for the tree
itself but make it useless for construction purposes and
reduce the market value of the timber.
Suckers, belonging to Cicalidae and Coccidae were
reported damaging roots (Hutacharern et al. 1988) and
leaves (Mathur and Balwant Singh 1961a). Lacifer lacca
(Coccidae), the insect involved in the production of lac,
is a sap sucker of Shorea talura, Shorea spp. and
Dipterocarpus tuberculatus (Mathur and Balwant Singh
1959, 1961a, b).
Termite attacks have been reported on living
dipterocarp trees (Wyatt-Smith 1958, Nuhamara 1977,
Sen-Sarma and Thakur 1980, Smits et al. 1991). Smits
et al. described termite attack on living Shorea
polyandra in Kalimantan: the trees shed their leaves,
while the crown became lighter and the death of the tree
was manifested by the exudation of many clumps of black
resin from the stem base.
Forest Products
Damage on logs and timbers are mainly caused by
termites and beetles. Since it is a field of economic
importance, many studies have been conducted on the
identification of the pests, their biology and control
methods.
Termites attacking logs and wood were studied in
Malaysia, Indonesia, India, China (Mathur and Balwant
Singh 1960a, b, 1961a, b, Becker 1961, Sen-Sarma 1963,
Abe 1978, Sen-Sarma and Gupta 1978, Hrdy 1970, Said
et al. 1982, Ping and Xu 1984, Dai et al. 1985,
Quiniones and Zamora 1987, Hutacharern et al. 1988),
but also in European and even Saudi Arabian laboratories
(Alliot 1947, Badawi et al. 1984, 1985). Tests on the
resistance of wood to termite attacks were widely
conducted (Alliot 1947, Becker 1961, Sen-Sarma 1963,
Schmidt 1968, Sen-Sarma and Gupta 1978, Hrdy 1970,
Dai et al, 1985, Badawi et al. 1984, 1985). Pentacme
suavis, Shorea guiso, S. robusta, S. obtusa, S.
stenoptera, Vatica astrotricha, Hopea hainanensis,
Dipterocarpus sp. proved to be resistant to termite
attack. In other studies wood from Dipterocarpus spp.