A review of dipterocarps - Center for International Forestry Research

Pests and Diseases of Dipterocarpaceae 119
was particularly susceptible to termite attack (Alliot
1947) and that of Vateria indica was preferred by
Microcerotermes cameroni (Hrdy 1970). Heavy
hardwoods, Neobalanocarpus heimii and Vatica sp.,
were the least susceptible species to termite attack.
Wood of Neobalanocarpus heimii, Shorea ovalis and
Shorea spp. contain repellants against Cryptotermes
cynocephalus (Said et al. 1982).
Ambrosia beetles (pin-hole borers) infest logs and
wood timber (Browne 1950, Bhatia 1950, Anon. 1957,
Anuwongse 1972, Fougerousse 1974, Garcia 1977,
Hutacharern et al. 1988). Browne reported the
susceptibility of Shorea leprosula logs to attack by
ambrosia beetles, more particularly Xyleborus
pseudopilifer which usually attacks only dipterocarps,
and X. declivigranulatus which is polyphagous. Shot and
pin-hole borers attacked barked-logs of Parashorea
malaanonan more severely than unbarked ones, as well
as logs left in the shade (Anon. 1957).
Insecticide trials against termites (Mathur et al. 1965,
Said et al. 1982, Schmidt 1968) found BHC, aldrex and
chlordane were effective. Preservatives, such as copperchrome-arsenic,
increased wood resistance to attack of
Coptotermes curvignathus.
Studies of treatment against insect damage on logs
and wood have been mainly conducted in India.
Insecticides such as BHC, fenpropathrim, fenvalerate,
permethrine, telodrine, diedrex, gammexane and to a
lesser extent chlordane were effective against beetles
such as Lyctus brunneus (Lyctidae), Cerambycidae,
Bostrichidae, Platypodidae and Scolytidae (Browne
1951, Menon 1954, 1958, Francia 1958, Thapa 1970,
Ito and Hirose 1980, Chatterjee and Thapa 1971,
Nunomura et al. 1980, Daljeet-Singh 1983). Thapa
(1970) showed that BHC offered a satisfactory
protection when sprayed on logs of Parashorea
tomentella against cerambycids and more particularly
Dialeges pauper and Hoplocerambyx spinicornis.
A minimum of 3 months immersion of Shorea
robusta poles in water gives protection against bostrichid
attack, most probably due to the leaching of sugars during
soaking (Anon. 1946). Fresh water and marine borers
have damaged boats and poles (Shillinglaw and Moore
1947, Anon. 1947, Edmonson 1949, Premrasmi and
Sono 1964, Mata and Siriban 1976, Chong 1979,
Santhakumaran and Alikunhi 1983, Chen 1985). Most
records concern marine borers, though nymphs of
species of mayfly (Ephemeroptera) burrow into and
damage boats and submerged wooden structures in fresh
water in Thailand (Premrasmi and Sono 1964).
The durability and resistance of dipterocarp timbers
and poles against marine borers, mainly in the genera
Martesia, Teredo, Nausitora, Dicyathifer,
Bactronophorus, Baukia, Nototeredo and Limnoria,
were studied by Shillinglaw and Moore (1947) and Mata
and Siriban (1976). Anisoptera polyandra in New
Guinea (Shillinglaw and Moore 1947),
Neobalanocarpus heimii and Shorea maxwelliana
(Chong 1979) had good natural resistance to shipworms
and other marine borers. A. polyandra is therefore
recommended for piling in new marine structures.
Shorea laevifolia has been reported as being resistant
to Martesia and Teredo species (Anon. 1947). In China,
Chen (1985) demonstrated that the resistance to marine
borers of hardwood is higher than that of softwood, and
heartwood is superior to sapwood. Edmonson (1949)
reported Martesia sp. destroyed rapidly apitong
(Dipterocarpus sp.) and Shorea sp. in the Philippines.
According to Santhakumaran and Alikunhi (1983),
Shorea robusta and Dipterocarpus indicus had a very
heavy attack whereas D. macrocarpus had a medium
attack and D. turbinatus and Hopea parviflora had a
moderate attack in 7-8 months by Martesia and Teredo
species. Some treatments with creosote proved to be
effective (Chong 1979, Mata and Siriban 1976).
Diseases
Seeds
Bacteria, viruses and especially fungi cause loss of seed
viability. Infection takes place on the tree, during the
flowering and/or development of the fruit, on the ground
at the fruit fall, and during the period from harvesting to
sowing in the nursery. During these stages, seed
contamination can occur with organisms causing diseases
in the nursery or serving as primary inocula for decay
organisms specific to seedlings (Mohanan and Sharma
1991). Seeds collected from the forest floor are more
liable to be infected by decay organisms. Fungal infection
also occurs during seed storage, where large quantities
of seeds in containers and high moisture are propitious
conditions for fungal development.
Over 100 species of seed fungi have been identified
in Malaysia (Hong 1976, 1981a, Lee and Manap 1983,
Elouard and Philip 1994), in Thailand (Pongpanich
1988), in Indonesia (Elouard 1991), and in India (Mittal