A Half-yearly Peer Reviewed Journal of Bangladesh Forest Research Institute
Diseases and disorders of rubber plant ( Hevea brasiliensis Muell.
Arg.) so far recorded from Bangladesh have been reviewed. An
important leaf spot disease caused by Corynespora cassiicolatfBa.rV.
Curt.) Wei in January, 1985 and a root rot by Fusarium sp. in
December, 1985 respectively at Ramu and Khagrachari rubber
nurseries have been described. A severe dieback of grafted rubber
seedlings at Kanchonnagar and Raozan rubber nurseries in 1985 was
found primarily owing to very poor new root regeneration on transfer
to polyethylene bag and secondarily due to the attack by Phomopsis
hevae (Petch) Boedijn. During October, 1985 about 50% mortality
occurred in bud wood nursery stock of alone PB—235 at Haludia
rubber estate because of the phytotoxic effect of Elite Paint 713 (TR-Blue).
Ganoderma pseudoferrum (Wakef.) Overecm and Steinm caused root rot
in 1972 .ubber plantation at Dantmara. Yellowing of rubber seedlings
of clone PBIGG at Khagrachari was due to nutrient deficiency.
The importance of seasoning of timber has been discussed in the
context of Bangladesh conditions. Prevalent seasoning practices have
been described. The potential of wood seasoning in the country and
its expected economic benefits have also been dealt with.
Members of Loranthaceae, popularly
known as misletoes, are semiparasitic angiosperms.
They mostly attack dicotyledons
and gymnosperms and cause more economic
loss than any other angiospermic parasite.
Birds play an important role in the dispersal
of mistletoes. Sunbirds and the flowerpeckers
are the main dispersal agents of the
broad leaved mistletoes (Ali 1931, Weeraratna
1959, Gill and Hawkworth 1961,
Singh 1962, Ghosh ct al. 1984). Davidar
( 1980) reported that frugivorous birds such
as bulbuls and barbets also helped in dispersal
of mistletoes. The ripe one-seeded
berry of mistletoes contains a sweet viscid
pulp surrounding the seed. During feeding,
the birds squeeze the viscid seed out of the
epicarp by their beak, throw the epicarp
and swallow and excrete the seed on to a
branch (Ali 1931). Davidar (1980) also
reported that a flowerpecker Dicaeum concolor
( Dicaeidae ) used a different technique
to disperse the seed. The flesh alone is
eaten, epicarp is dropped and the seed is
rubbed off from its bill on to a branch.
During 1976 keora (Sonneratia ape-tala
Buch.—Ham.) seedlings were planted at
1.2 m x 1.2 m spacing along the coastal
belts of Bangladesh by the Forest Department.
Though large scale mangrove plantations
were initiated during the past ten
years, thinning could not be undertaken
owing to a lack of a thinning schedule.
Currently, thinning is being carried out
experimentally in different plantations. Data
relating to growth and natural mortality
are being collected and will form the basis
of a thinning prescription.
Members of Loranthaaeae are semiparasitic
angiosperms and are popularly
kn.own as mistletoes. They cause more
economic loss than any other angiospermia
parasites. They mostly attack dicotyledors
and gymnosperms which include horticultural
plants as well as forest trees. Control
of mistletoes has been advocated and
practised throughout the world. Gill and
Hawksworth (1961) suggested (i) physical
removal and (ii ) chemical control as direct
control measures. Silvicultural management
system like thinning and use of
isolation strips have been stated to be effective
in reducing the infestation and spread
of dwarf mistletoes (Greenham and Hawksworth
1964 ; Hawksworth et al. 1977).
Certain amount of natural control exists
in some areas where particular insectsand
fungi reduce the infestation (Greenham
and Hawksworth 1964). Gill and Hawksworth
(1961) g?.ve brief notes on insect
attack of dwarf mistletoes. Approach
towards the biological control of mistletoes
by insects has been indicated by Hawksworth
(1971 ) and Smith and Funk ( 1980 ).
Graves and Graves ( 1980) noted that the
larvae of Citheronid regalis ( Citheronoiidae :
Lepidoptera) feed on the leaves of
Safety matches are a consumer item
of everyday use. There are about twenty
safety match factories located mostly in
the southern part of Bangladesh. In 1984-85
the country produced 940 million gross
boxes of safety matches (Anon. 1985).
This quantity is enough to meet the entire
demand of the country. At present there
is no export of this commodity presumably
because of scarcity of suitable timber species
and strong competition in the international
market. The traditional species
used in Bangladesh have different unattractive
tints.
Sundri wood chips were subjected to a mild chemical pre-treatment
by soaking them in 1,2 and 3% solutions of NaOH and NaiSCh,
individually as well as in mixture, for 24 hours at atmospheric conditions.
Hardboards made from pre-treated chips were tested for determining
their strength and water resistance properties. It was observed
that the boards made from the chips pre-treated with NaOH alone
and in mixture with Na2SO3 were stronger than those made by simple
steam softening of the chips prior to refining. Also the strength of
the hoards increased with an increase of the concentration of the pretreatment
solutions. Pre-treatment with NaOH alone produced stronger
boards than with the mixtures. Any such effect on the strength
property of the boards, however, was not obvious in the pre-treatment
with Na2 SO3 solutions. AU the pre-treatment methods adversely
affected the water resisting properties of the boards.
Calamus longisetus Griff. (Palmae) has
been recorded to be distributed in Andaman
Islands, Burma, Thailand, Indonesia and
Malay Peninsula (Beccari and Hooker
1892-93 ; Blatter 1926 ; Dransfield 1979 ;
Basu and Basu 1987). The various floristic
works by. Becaari and Hooker ( 1892—93),
Prain (1903a; 1903b), Brandis (1906),
Heinig ( 1925), Raizada (1941 ), Sinclair
(1955) and Khan et al. (1984), have not
recorded its occurrence in the region now
under Bangladesh.
Kraft pulping of whole jute plant without retting was conducted
in the laboratory scale. Compared with kraft pulping of bamboo,
the unbleached pulp yield with unretted jute plant was lower by about
3.0 percent points at the same point of delignification. The yield
was lower by 17.0 percent points compared to kraft pulping of jute
bast fibre. Jute plant pulp degraded severely on bleaching. However,
the quality of unbleached pulp was almost similar to kraft bamboo
pulp. Whole jute plant can thus replace bamboo in making papers
which do not require bleaching.
Data on the availability of different sizes of fruits, seed production
according to size classes, germination success and viability of
seeds of Sonneratia apetala Buah—Ham. were collected during 1984—
85 from the Chittagong coastal area. The fruit dropping period
extended from late July to early October. Fruit size varied and proportion
of medium sized fruits was h:gh. No significant difference in
germination success was detected when seeds from different fruit size
classes were collected and sown. Viability of seeds declined with
passage of time in the laboratory as well as under field conditions.
No seed germinated in the field when sown after 60 days of fruit
collection.
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