INBAR_Technical_Report_No13_04..PDF133
This is a polyphagous species and a common pest of
packing cases, plywood chests and other wood-based
industrial products. It is a minor pest of dry bamboos.
The adult beetle is black, 6-15 mm long, cylindrical
and with a rough hooded prothorax, usually with
curved hooks at the distal ends of elytra. Female adult
lays eggs singly on rough surfaces of dry bamboos.
The larvae, after hatching, bore into the soft portion
and gradually make a wide tunnel. The tunnels are
tightly packed with fine wood dust and the host
bamboo is soon reduced to powder. The life cycle of
the beetle is annual.
Dinoderus pilifrons Lesne, Cryphalus satonis Mat. and Heterobostrychus hamatipennis Lesne.
Powder-post Beetles (Coleoptera: Lyctidae)
are quiet common, they cause much less damage to
bamboos than bostrychid beetles.
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BIOLOGY
The beetle is flat, light brown to almost black in colour,
and about 2-7 mm long. After hatching, larvae start
feeding on wood tissues converting it to a very fine
powder, which remains closely packed in the tunnel.
Moisture content of less than 10% is unsuitable for
development of the larvae. After about one month of
pupal period, beetles emerge by cutting approximately
circular holes. The life-cycle varies from one to three
years, depending on the availability of food and
moisture within the wood.
recommended (Sandhu 1974).
? Lyctus brunneus Stephens
Southeast Asian countries.
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BIOLOGY
This is a major boring pest on timber of various
broadleaf tree species and woody products, but cause only minor damage to bamboo. The adult beetle is 2.2-7 mm long and varies from light brown to reddish-brown in colour. The protergum of the adult is rectangular, with a clearly longitudinal, Y-shaped suture on it. Both adults and larvae bore coaxially to the culm fibre. There is one generation per year. Adults emerge throughout the spring and summer months. Larvae occur from May to the following March and pupate in tunnels when fully grown (Chen Liang 1983).
? Other Powder-post Beetles
The Chinese powder-post beetle, Lyctus sinensis Lesne, is widespread in tropical and subtropical areas, especially in Southeast Asian countries. It attacks timber of many trees, including bamboos. The adult beetle is 3-6 mm long, 0.8-1.2 mm wide and dark brown in colour. The protergum of the adult is oblong and the longitudinal suture on it is not prominent. This beetle has an annual life cycle and overwinters as larvae in tunnels. Both adults and larvae bore in dried culms and finished products, and the damaging process can last for over eight years. Tillus notatus Klug,Tarsostenus univitatus Rossi and Chelifer sp. prey on the larvae and pupae of the borer (Zhan Zhongcai 1983).
Minthea rugicollis Walker is widespread in tropical and subtropical regions. The adult is 2.3-2.8 mm long and covered with greyish-white hair. The protergum is concave in the centre. There are three generations per year. Both adults and larvae feed on dried wood materials throughout the year, but are relatively less
active in the winter season.
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are also effective for these lyctid borers.
Long-horned Beetles (Coleoptera: Cerambycidae)
DISTRIBUTION
Newly felled culms, which are less than 2 cm in
diameter, of Phyllostachys and Pleioblastus species.
BIOLOGY
Adult beetles are 13-18 mm long, 4-4.5 mm wide and
varies from grey to dark brown in colour. There is one
generation per year, overwintering as adults in the
tunnels bored. Adults come out in April and feed on
young twigs, newly-sprouted leaves and culm tissue.
Female adults make splits on culms selected for egg-
laying and deposit eggs into culm cavities. Eggs are
laid individually, with only one egg per culm in most
cases. Larvae, occurring from May to October, feed on
the inner surface of the culm, making shallow tunnels,
and repeated feeding causes the damaged culm to thin
down and become susceptible to collapse in wind
(Zhang Xiankai and Zuo YX 1988).
? Tiger longicorn - Chlorophorus annularis Fabricius
DISTRIBUTION
Thailand and Vietnam.
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HOSTS
Primarily on felled Phyllostachys spp., Bambusa spp. and Dendrocalamus spp. culms, but also on apple, Chinese sweet gum, teak and cotton tree trunks.
BIOLOGY
The adult beetle is 9.5-17 mm long, 2.4-2.5 mm wide
and ochre yellow in colour, with dark brown or black
curved markings on the elytra and pronotom.
Normally, there is one generation per year. However,
larval development rate is affected by the dryness of
the culm, and may continue even after the culm has
been made into products. Adults occur from April to
September and eggs are laid on cut ends or in cracks.
Larvae overwinter in tunnels in the culm.
? Ceresium sinicum White
This is an important wood borer, the larvae of which
attack felled logs of various trees, including bamboos.
The adult beetle is 10-15 mm long, 2-3.5 mm wide
Fig. 59: Adult of Chlorophorus annularis
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and brown or light brown in colour. The protergum is
irregularly marked, but has a smooth, longitudinal
ridge (carina) at its centre. There is one generation per
year. Adults emerge in May, and eggs are deposited
onto culm tissue through wounds and cracks. Larvae
bore in the culm wall, forming vertical tunnels, and
overwinter in the tunnel when fully grown.
Paracerchysius ceresii,Zombrus bicolor and Scleroderma sp. parasitize larvae and pupae of the beetle (Zhan
Zhongcai 1986).
? Other Long-horned Beetles
The teak trunk borer, Stromatium barbatum Fab., is primarily a pest of packing cases, seasoned timbers,
furniture, plywood, and wood work in building. It
also attacks bamboos. The beetle deposits eggs in small
holes on rough surfaces of the host wood. The larval
tunnels are cylindrical and tightly packed with fine
wood dust, which is normally ejected out at intervals.
Fig. 60: Adult of Stromatium barbatum
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scraping of wood with mandibles.
Other common long-horned beetles attacking post-
harvest bamboo include Chlorophorus figuratue Scop, Glenea notata Gahan, Niphona hookeri Gahan, Diboma posticata Gahan, Merionoeda nigriceps White, Purpuricenus sanguinolentus Oliver and Ropica signata Pic.
Termites
and Daman). The attack is usually serious, and the
Fig. 61: Adult of Diboma posticata and the damage caused
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140
excavations, to be ruined within a short period. All
types of bamboo constructions, including split
bamboos used as rafters or matted walls in houses,
are seriously attacked. The attack by this species
resembles a typical bostrychid attack with small holes
appearing on the outer portion (Chaudhry 1955; Sen-
Sarma and Mathur 1957; Sen-Sarma et al. 1975;
Thakur 1988a).
attacking wood and bamboo structures, bamboo poles
and matted or split bamboos in Bangladesh, India and
Myanmar. This species builds narrow, covered earthen
runways or broad sheaths of mud plaster on the
surface of felled or cut bamboos on the ground (Beeson
1941; Bhasin et al. 1958).
Coptotermes heimi Wasm. (Isoptera: Rhinotermitidae) is a highly polyphagous species with as many as 35
species of host plants, in addition to bamboos. It is
found associated with bamboo in India and Pakistan.
The pest eats away the inner soft portion along the
fibre, leaving the outer surface intact. In seriously
infested bamboos, the inner portion looks like a
honeycomb.
clumps, making numerous honeycomb cavities
(Beeson 1941; Roonwal 1970).
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pests in the Asian region. The damage they cause and
the threat they pose to bamboo-based industries have
been identified in some countries as more large-scale,
intensively managed plantations are being established.
Various control measures against outbreaks of insect
pests have been developed, but most of these involve
the application of chemical insecticides. Besides
polluting the environment, the use of large amounts
of chemical insecticides also removes the natural
enemies of pests, thereby weakening natural control
systems and shortening the interval of outbreaks.
Therefore, the long-term plan and related strategies
that address insect pest problems on bamboo should
be based on integrated management measures.
Integrated pest management (IPM) is the
comprehensive approach that considers all available
measures as a whole to solve pest problems. Although
an IPM program for bamboo is not readily available
yet, investigations are being undertaken and the
approaches will include silvicultural, biological, direct
and chemical controls.
all possible cultural measures to ensure that the plants
are exposed to the least possible pest-stress. When
managed properly, silvicultural control can be an
effective way to minimize insect damage and hence, is
considered primary to IPM.
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is achieved mainly through proper tending, regulating
culm density and age structure, and regenerating the
stands. These measures aim to kill pest insects directly,
create unfavourable environment conditions for the
pests and improve the insect-resistant ability of the
plants.
water supply conditions at the site and enhance the
vigour of bamboo plants. If undertaken in winter
months, it is effective in suppressing the population
of those species already living, overwintering or
diapausing in the soil, either by directly killing or by
exposing them to unfavourable weather conditions and
natural enemies.
Direct Control This approach to pest control targets the reduction of
pest population through mechanical or physical means.
Aiming to prevent numerical build-up of insects or
reduce the damage caused by them, direct control
measures in bamboo stands often employ removing,
trapping and setting physical barriers to pests. These
measures are designed according to common or specific
behaviour of target insects and can be very effective
though labour-intensive. Direct control approach needs
a detailed understanding of the biology and life history
of the target insect pests.
Adults of a number of insect pest species attacking
bamboos, especially those in the lepidopteran species,
are active at nights, displaying strong phototaxis.
Light-trapping at nights during adult stage can
significantly reduce larval density. Mass-trapping in
this manner has proven practical and successful in
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China. Devices required for this are simple, and a
choice of types is available to suit the insect species
involved, size of stands and user preferences. Black
fluorescent light lamp is the one employed most
commonly. The lamp can be set at an open place
nearby or in the stand. It is kept about 1-1.5 m above
the ground, and a container with an aqueous
insecticide solution is placed below the lamp, or an
electric fence is set beside or around the lamp to kill
the attracted insects. Best results are obtained in dark,
hot and windless nights.
Some insects that feed on bamboo are attracted to a
particular food or odour. Such behavioural responses,
referred to as chemotaxis, can also be used in
controlling the pests. Toxic baits or traps can be very
effective in suppressing the population of such insects.
Both adults and nymphs of bamboo locusts, for
example, prefer salty food and uric odour, and mass
trapping can be achieved using pots containing a
mixed solution of bittern and insecticides. Similarly,
large number of adults of all bamboo shoot fly species
can be captured and killed by traps baited with sweet
and sour materials, or using fresh bamboo shoot
pieces treated with insecticides. In case of bamboo leaf-
rollers, adult moths need to feed on flower juice and
show a strong preference to oak and chestnut trees.
As a long-term measure, some of these trees can be
planted to serve as traps, and satisfactory control can
be achieved by spraying the trees with insecticides
when the moths gather on them in swarms to feed.
Setting physical barriers to deter insects from reaching
the point of attack is commonly used to control forest
insect pests. It is particularly effective against insect
species that crawl to reach host plants. As far as
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144
bamboo is concerned, the most successful use of this
method is in the control of the stink bug, Hippotiscus dorsalis, which feeds on culms and branches. The bug has an annual life cycle and overwinters as nymphs
on the ground. The wingless nymphs move onto culms
by crawling in the spring season. Setting sticky or
adhesive barriers around the basal part of culms in
early spring can prevent the overwintering nymphs
from reaching the culm. The bugs accumulated on
culms under the barrier can be killed using methods
such as spraying contact insecticides.
Removal of insects from their habitat and host plants
is the simplest way among direct control measures. It
is very effective in some cases to alleviate pest pressure
on bamboo plants and practical in small-scale stands
or isolated plantings. The damage caused by bamboo
shoot weevils can be significantly reduced by removing
adult weevils from bamboo shoots by hand-picking
before any egg-laying occurs, because adult weevils of
these species will drop to the ground when disturbed.
Eggs of tussock moth are mainly deposited in groups
at the basal part of culms, and can easily be removed
or destroyed to significantly reduce larvae population.
Some other insects, which feed in groups at the basal
portion of culms or on leaves of lower branches, can
also be physically removed.
Biological Control Almost all insect pests are attacked by a number of
other living organisms, which are their natural
enemies. The use of such organisms to suppress
population density of insect pests and the damage they
cause is referred to as biological control, and has become
an important IPM component. The natural enemies of
insect pests are often grouped as parasitoids, predators
and pathogens. Parasitoids are insect species that
Insect Pests of Bamboos in Asia INBAR
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most important species are hymenopteran wasps and
dipterian flies. They feed as larvae on host insects
during egg, larva or pupa stages, and cause the death
of the hosts when they complete their own
development of larval stage. Predatory natural
enemies of insect pests include a variety of mammals,
birds, spiders and other insects. Various species of
bacteria, viruses and fungi are pathogenic to insect
pests. The use of insect pathogens and their products
has become a major tool for biological control.
In natural bamboo stands, the bamboo eco-system
remains mostly intact as biodiversity and natural
enemies of pests play important roles in regulating
insect pest populations. However, when bamboos are
cultivated intensively, such as in large-scale pure
plantations, biodiversity hardly exists. Besides,
complete weeding and use of large amounts of
chemical insecticides destroy the habitat and food
resources of natural enemies and the natural control
reduces sharply. Inundative release of natural enemies
to control insect pests on bamboos has been practised
successfully in some countries, but this method does
not offer long-term control. Conservation of natural
enemies is an important strategy of biological control
aiming to sustain environmental conditions
favourable to natural enemies. Measures such as
retaining the surrounding vegetation and reducing
the use of chemical insecticides form parts of such a
strategy.
chemical control is highly effective, easy to use and
INBAR Insect Pests of Bamboos in Asia
146
low in cost. It is an important approach and the most
widely used in insect pest management. A number of
insecticides are available, varying in structure,
formulation and action. The choice of insecticide is
made according to the insect and host species involved,
available equipment, and application techniques.
Insecticides can be applied to standing bamboo plants
by dusting, spraying, injecting and smoking. Dusting
with insecticide is an economical way for controlling
bamboo leaf feeders. Mist-spraying ? emulsifiable
concentrates or wettable powders diluted in water and
applied using mist blowers ? is the most widely used
technique and is effective against almost all leaf feeders
and some sap suckers on bamboos. Smoking is
recommended for controlling bamboo leaf feeders and
some sap suckers in stands which are high in density
or located in mountainous areas. It is important that
smoking be done in windless weather, usually in the
early morning or later afternoon. Systemic insecticides
can be absorbed and transmitted by plant tissues and
hence, has an important place in pest management in
forests. The application of systemics by injecting into
the culm cavity or applying to the root system has
been particularly recommended and, because it is
relatively safe to natural enemies and environments,
it is being widely used in China for controlling insect
pests ? including leaf feeders, sap suckers, shoot borers
and gall makers ? on monopodial bamboos with large-
sized culms.
broad-spectrum and hence, highly toxic to mammals
and natural enemies. Repeated use of large amounts of
chemical insecticides also induces resistance in insects
and results in environmental hazards. Chemical control
is to be considered only when other management
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Selection of the correct insecticide, application method
and timing play a critical role in minimizing the use
of chemicals and their environmental impacts, while
optimizing beneficial results.
Management of Post-harvest Pests Stored bamboos and finished products are susceptible
to attack by boring insects, mainly shot-hole, powder-
post and long-horned beetles. This is a serious problem
in most bamboo-growing nations. Effective control
measures are reported from many countries, and can
be grouped as pre-harvest and post-harvest
treatments, the latter involving prophylactic
measures.
and timing of harvesting. There are reports that
correlate the damage level in felled culms to application
of fertilizers in bamboo stands, culm age and season
of felling, although not much experimental data are
available to support this. It is generally believed that
attack of borers on bamboos is highest when the
harvesting is done during the full moon phase. Some
studies have shown that the moisture level in culms
increases with the waning of the moon and decreases
with the waxing of the moon. This fortnightly
rhythm in relative moisture content is the only lunar
periodicity known to occur in the metabolism of the
growing bamboo. However, it may be added that no
relation has been found between the moisture content
of freshly cut bamboo and its subsequent
susceptibility to borer attack. Nevertheless, felling of
bamboos based on the moon?s phases is a traditional
method practised to reduce borer incidence.
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The correlation of the starch or total sugar content of
the bamboo and beetle attacks is a point of much debate
(Dhamodharan et al. 1986; Kumar et al. 1994). Some
traditional methods of checking insect incidence by
controlling starch content include felling of bamboo
when the sugar content is low, felling of bamboo at
full maturity, post-harvest transpiration of bamboo
culms, and water soaking of bamboo to leach out
soluble sugars and carbohydrates. Singh (1974)
showed that starch content of bamboo is not related
to the age of the culm, although flowered bamboo
may show a reduction in the starch content. There are
also many factors other than the starch content that
may influence borer attack, and how these factors
interact with the starch content needs to be studied in
detail.
cypermethrin 0.4% in diesel oil or endosulphan 0.75%
in diesel oil against ghoon borer attack (Thapa et al.
1992); treatment with 1% sodium pentachlorophenate
or sodium pentachlorophenate:boric acid:borax
mixture (Kumar et al. 1985), etc. It is also sugge
