COMMUNICATION I Kesan Pendedahan Racun

Pertanika 12(1), 43-46 (1989)
-
COMMUNICATION I
Kesan Pendedahan Racun Karbaril terhadap
Tumbesaran dan Pembiakan Aphis craccivora Koch
ABSTRAK
Dalam kajian ini kesan beberapa kepekatan racun karbaril terhadap beberapa parameter jadual hayat Aphis
craccivora Koch telah diselidiki. Telah didapati bahawa karbaril pada kepekatan melebihi 0.0106% b.a.
dapat membunuh krsemua nimfa instar awal Pendedahan pada kepekatan ini pula mengakibatkan kelewatan pembiakan selama tiga hari pada tiga peratus daripada populasi dewasa yang telah didedahkan dan
umur hidupnya hanya 10 hari, iaitu suatu kesingkatan hayat yang bererti berbanding dengan 29 hari dalam
kawalan. Nilai-nilai parameter jadual hayat juga menunjukkan bahawa populasi aftd yang berkenaan tidak
akan bertambah dan oleh itu tidak mampu melanjutkan hayatnya ke generasi hadapan. Sebaliknya terdapat
8% yang mencapai kedewasaan bagi populasi yang terdedah kepada kepekatan 0.0052% b.a., 40% bagi
kepekatan 0.0027% b.a. dan 68% bagi kepekatan 0.0013% b.a.
ABSTRACT
The effects of several concentrations of carbaryl on the life-table parameters of Aphis craccivora Koch were
studied. It was revealed that all the early nymphal instars died after being exposed to carbayrl at concentration in excess of 0.0106% a.L Exposures at this concentration however, resulted in a 3-day delay in reproduction in 3% of the tested population and experienced a significantly shorter life span of 10 days when
compared to 29 days in the control. Values for the life-table parameters also indicated that these populations
would not grow and thus would be unable to continue into the next generation. In contrast, 8% of the population exposed to 0.0052% a.i. reached adulthood, 40% for those exposed to 0.0027% a A. and 68% for
those at 0.0013% a.i.
PENGENALAN
Afid atau kutu daun melalui kitaran hidup yang
agak luar biasa dan lazimnya mempunyai kadar
pembiakan yang tinggi. Ianya berkebolehan
melahirkan progeni secara berseks atau tidak
berseks, iaitu partenogenesis. Di dalam iklim
tropika seperti Malaysia ini afid Aphis craccivora
Koch yang merosakkan tanaman kekacang,
kukurbit, dsbnya, membiak dengan cepat
dengan ketiadaan halangan dari faktor cuaca.
Pada suhu serta kelembapan yang tinggi kadar
pembiakan dan kesuburan afid ini adalah tinggi
juga (Radke, et al, 1972).
Selain dari menghisap cairan sap tanaman, afid ini juga berkemungkinan berfungsi
sebagai vektor penyakit virus pada tanaman
kekacang, cili dan kukurbit. Oleh itu kawalan
kimia secara meluas bukan lagi perkara asing.
Pada kes-kes tertentu racun serangga pada
kepekatan submaut telah merencatkan pembiakan serangga dan hamama (Hall, 1979Jones
dan Parrella, 1984). Ada juga kes-kes lain yang
menunjukkan perangsangan racun serangga ini
menyebabkan kenaikan kadar pembiakan yang
lebih tinggi, iaitu suatu keadaan yang digelar
hormoligosis (Luckey, 1968). Di Tamil Nadu,
India, populasi Aphis gossypii telah didapati bertambah sungguhpun semburan racun serangga
telah dilakukan. Keadaan ini telah dikaitkan
dengan letusan semula populasi akibat rangsangan pembiakan yang tebih tinggi pada
kepekatan submaut di lapangan (Sithananthan,
et al., 1973).
Kajian ini telah dijalankan untuk menentukan kesan racun karbaril terhadap keupayaan
pembiakan A. craccivora Koch.
BAHAN DAN KAEDAH
Kultur Afid
Kultur stok telah dimulakan dengan seekor afid
betina yang dipelihara pada pokok kacang
YUSOF BIN IBRAHIM DAN WONG KUAN YEOW
tanah, Arachis hypogaea var. Matjan, dalam insektarium pada suhu 24°C - 32°C dan kelembapan bandingan 46% - 90%. Pokok-pokok
kacang tanah ini telah dipastikan bebas dari
serangan Iain-lain serangga dan penyakit. Kesegaran kultur stok ini dijaga dengan mengawal
saiz populasi dan menyalinkan pokok-pokok
kacang tanah yang segar setiap empat hari.
Rawatan
Untuk rawatan, nimfa-nimfa instar pertama dari
generasi ketiga yang telah dilahirkan dalam
jangka masa 24 jam telah digunakan.
Sebagai substrat rawatan, pokok kacang
tanah yang subur dan berumur 10 hari telah
digunakan. Setangkai daun yang tidak terasing
dari pokoknya telah dicelupkan ke dalam bancuhan rawatan racun karbaril atau air suling
dan dibiarkan kering udara selama setengah
jam. Bancuhan rawatan racun karbaril (Sevin
85WP) yang digunakan ialah pada kepekatan
0.0106%, 0.0053%, 0.0027% dan 0.0013% serta
air suling yang merupakan rawatan kawalan.
Seterusnya, nimfa instar pertama telah dipindahkan secara cermat dengan berus halus (000
Series Finest Sable, Winsor & Newton) kepada
daun yang telah dirawat. Nimfa afid ini kemudiannya membesar di dalam sangkar mikro yang
diperbuat dari dua potongan paip PVC bergaris pusat 5 cm setebal 5 mm sebagai rangka.
Sangkar mikro ini ditutupi dengan kepingan
PVC lutsinar nipis yang berlubang-lubang halus
untuk penyaliran udara. Dalam membentuk satu
sangkar mikro, tetali span dikepitkan di antara
dua rangka PVC tersebut untuk mengelakkan
tangkai daun daripada tercedera. Untuk menjamin kesihatan afid dan mengelak pertumbuhan kulat, sangkar mikro ini sentiasa dibersihkan dari madu serangga dan wap air.
Data dan Penganalisisan
Setiap hari pada waktu yang sama bilangan afid
yang mati dan yang masih hidup, iaitu data
kemandirian, serta nimfa yang dilahirkan telah
dicatat bagi setiap afid secara individu sehingga
ianya mati. Setelah dibilang, nimfa-nimfa telah
dinyahkan daripada sangkarnya. Prosedur
jadual hayat standard telah diikuti dalam membuat penganalisisan data untuk mengira parameter-parameter seperti kadar pembiakan kasar
(GRR), kadar pembiakan bersih (Rf)), kadar
intrinsik pertambahan (r) dan masa purata
generasi (T) (Southwood, 1978). Min daripada
empat replikat yang setiap satunya mengandungi 10 afid bagi setiap rawatan telah dibandingkan dengan cara analisis varian dua hala
dan ujian julat berganda Duncan (DMRT).
KEPUTUSAN
Kadar kemandirian terkhusus umur bagi A. rraccivora setelah dirawat dengan beberapa kepekatan racun karbaril (Rajah 1) telah didapati
menurun bersamaan dengan kenaikan kepekatan rawatan. Masa tumbesaran nimfa ke
dewasa ialah 4 hari. Bagi rawatan yang terpekat
sekali (0.0106%), hanya terdapat tiga peratus
nimfa afid yang mencapai peringkat dewasa
berbanding dengan 98% dalam kawalan. Seterusnya, terdapat lapan peratus mencapai
kedewasaan bagi kepekatan 0.0052%, 40% bagi
kepekatan 0.0027% dan 68% bagi kepekatan
0.0013%. Rawatan pada dua kepekatan tertinggi
juga mengakibatkan umur afid pendek, iaitu 10
dan 12 hari jika dibandingkan dengan 29 hari
dalam kawalan.
Rajah 1. Kemandirian Aphis craccivora Koch yang
dipelihara atas pokok kacang tanah yang
telah dirawat dengan karbaril di dalam
keadaan insektarium.
Secara amnya, corak pembiakan A. cracdiwaadalah agak sama bagi kesemua kepekatan
rawatan (Rajah 2). Kadar pembiakan didapati
lebih tinggi pada peringkat awal dewasa yang
kemudiannya menjadi semakin berkurangan
mulai umur lapan hari. Puncak pembiakan pada
kesemua rawatan ialah pada hari ketujuh ke-
PERTANIKA VOL. 12 NO. 1, 1989
KESAN PENDEDAHAN RACUN KARBARIL TERHADAP TUMBESARAN DAN PEMBIAKAN A CRACCIVORA KOCH
cuali afid yang dirawat dengan 0.0106% b.a.
yang mana puncak pembiakannya hanya dicapai pada hari kesepuluh. Tambahan pula
puncak pembiakannya didapati 41 kali lebih
rendah daripada kawalan. Bagi kepekatan yang
lebih rendah, pendedahan kepada 0.0053%,
0.0027% dan 0.0013% masing-masing menunjukkan puncak pembiakan 29, 2.4 dan 1.3 kali
lebih rendah daripada kawalan. Panjangnya
jangka masa pembiakan juga didapati lebih
pendek bagi afid yang dirawat berbanding
dengan kawalan. Pada kepekatan 0.0106% dan
0.0053%, afid hanya berupaya membiak selama
empat dan lapan hari sahaja berbanding dengan 22 hari pembiakan bagi kawalan. Ini bermakna masa pembiakannya telah dipendekkan
5.5 dan 3.0 kali berbanding dengan kawalan.
Jadual 1 menunjukkan parameter-parameter jadual hayat afid yang telah dirawat dan
dipelihara di atas pokok kacang tanah. Pada
kawalan didapati bahawa kadar pembiakan kasar
(GRR) ialah 47.06 nimfa dan kadar pembiakan
bersih (Ro) ialah 42.13 nimfa. Kedua-dua parameter ini memberikan nilai yang agak tinggi
dan menunjukkan perbezaan yang bererti setidak-tidaknya bagi afid-afid yang telah dirawat
dengan kepekatan karbaril yang melebihi
0.0053%. Begitu juga halnya dengan masa
purata generasi (T) yang telah dipendekkan
dari 11 kepada 5 hari pada kepekatan 0.0053%
dan 2.6 hari sahaja pada kepekatan 0.0106%
yang mana telah mengakibatkan berkurangnya
kadar pertambahan saiz populasi. Ini amat
ketara sekali apabila dilihat dari segi kadar
intrinsik pertambahan (r) yang mencatatkan
pertumbuhan negatif dan juga dari segi kadar
J.2
16
20
Umur ( H a r i )
Rajah 2. Kesuburan Aphis craccivora Koch yang
dipelihara atas pokok kacang tanah yang
telah dirawat dengan karbaril dalam keadaan
insektarium.
finit pertambahan (X) populasi yang mencatatkan nilai kurang dari satu. Parameter masa
ganda dua (DT) tidak menunjukkan perbezaan
yang bererti (P=0.05).
JADUAL 1
Jadual hayat Aphis craccivora Koch yang
dipelihara atas pokok kacang tanah yang telah dirawat dengan karbaril dalam insektarium.
Parameter
Kepekatan
(% b.a.)
0.0106
0.0053
0.0027
0.0013
Kawalan
GRR
2.25a
2.38a
41.46b
43.93 b
47.06b
0.225a
0.450a
15.401 b
27.670c .
42.130d
T
r
31
DT
2.61 a
5.07a
11.06b
11.29b
11.31 b
- 0.053a
- 0.003 ab
0.250bc
0.290c
0.330c
0.25a
0.46a
1.28b
1.34b
1.39b
-17.32 a
3.02a
2.81 a
2.42a
2.12a
Min-min dalam ruang yang sama dan diikuti dengan huruf yang sama adalah tidak mempunyai perbezaan yang bererti
pada paras P < 0.05 setelah diuji dengan ANOVA dua hala dan DMRT.
PERTANIKAVOL. 12 NO. 1, 1989
45
Pertanika 12(1), 47-51 (1989)
COMMUNICATION II
The Rate of Litter Production in Mangrove Forest at Siar Beach,
Lundu, Sarawak
ABSTRAK
Penyelidikan kadar pengeluaran sesampah huian bakau telah dilakukan di Pantai Siar, Lundu, Sarawak.
Huian ini mempunyai sembilan spesies pohon; spesies pohon yang dominan ialah Rhizophora mucronata,
sementara R, apiculata sebagai spesies kodominan. Kadar pengeluaran sesampah ialah 5. 72 t/ha/tahun,
dan dari jumlah ini 4.49 t/ha/tahun (78.5%) adalah serasah daun. Corak kadar pengeluaran sesampah
dan serasah daun berubah antara satu bulan dengan lainnya. Pengeluaran sesampah antara bulan April
hingga Jun dan Disember hingga Februari lebih banyak berbanding dengan bulan-bulan lain.
ABSTRACT
A study of litter production was conducted at Siar Beach, mangrove forest, near Lundu, Sarawak. There are
nine species of trees in this forest of which Rhizophora mucronata is the dominant and R. apiculata is the
co-dominant species. The rate of litter production xoas 5.72 t/ha/year, and of this 4.49 t/ha/year (78.5%)
was leaf litter. 'The production of litter fluctuates being higher during April to June and December to February
compared to other months.
INTRODUCTION
Mangrove trees serve many functions. The
ecological functions of mangrove as a land
builder and coastline stabilizer have been
described by McNae (1974) and de la Cruz
(1979). Heald and Odum (1970) described
mangrove as a spawning and nursery area for
fishes and prawn. These functions, are closely
related to the primary productivity of the
mangrove. Several authors have conducted
studies on the relationship of primary productivity of mangroves and its ecological and economic functions (e.g. Golley et al. 1962; Heald
and Odum 1970; Odum 1971). They found
that most of the organic debris that enriched
the estuary were derived from adjacent mangrove forest. Thus, litter production plays an important role in maintaining the fertility of the
mangrove ecosystem and supply of food material to the faunal life (Srivastava 1980). However, the rate of litter production varies from
place to place, and between species dominating
the site (Mathias 1974). Such differences can
be seen from the work of Heald (1971) in
Florida, Christensen (1978) in Thailand and
Gong et al. (1984) in Matang mangrove forest,
West Malaysia.
The production of litter of the mangrove
forest at Siar Beach, near Lundu was studied in
order to understand more about the productivity of mangrove ecosystems in Sarawak.
Study Area
The study area is located at Siar River Estuary,
between latitudes 109° 52' E to 109° 53' E and
longitudes 1° 44' to 1° 45' N (Wolfenden and
Haile 1963). The estuary is about 12 km N - E
of Lundu (Fig. 1). The river is about 2 m wide
at low tide and 4 m wide at high tide.
The area is dominated by Rhizophora
mucronata and R. apiculata is co-dominant
(Saberi 1984). The other species that can be
found in the area are Bruguiera gymnorrhiza, B.
parviflora, B. cylindrica, Avicennia alba, Lumnitzera
sp., Nypa fruticans, Oncosperma sp. and a fern
Acrosticum sp.
The soils of the area derived from biotite
adamellite rocks. The climate is reasonably wet,
highest precipitation occurring in January, and
lowest in March. The total precipitation is 4260
mm per year. The temperature varies between
SABERI OTHMAN
SOUTH CHINA SEA
Kuching
u
Fig. 1. Star beach of Lundu, Sarawak.
48
PERTANIKA VOL. 12 NO. I, 1989
1 ° 4 1 ' N-
THE RATE OF LITTER PRODUCTION IN MANGROVE FOREST AT SIAR BEACH, LUNDU, SARAWAK
25° - 28°C, the lowest being in January and
higher in May (Fig. 2).
The total small litter and leaf litter production varies between forest and climatic
regions. Generally leaf litter accounts for more
than 50% of the total litter produced. However,
the amounts of this litter may vary depending
on the size of the traps used. For some forests,
particularly mangrove, leaf litter could reach as
high as 80%. A similar high percentage (78.5%)
of leaf litter was detected in the mangrove forest
at Siar Beach (Fig. 3).
50"
40
Fig. 2. The climatic diagram for Kuching, Sarawak.
MATERIALS AND METHODS
Plant litter was collected in a trap made of sailcloth, with a square wooden-frame opening
measuring 50 x 50 cm. The trap was placed lm
above the ground. Fifteen such litter traps were
sited randomly beneath the trees, and their
contents were emptied at the beginning of each
month. The litter was sorted into leaves and a
miscellaneous component. The litter was washed
and oven-dried at 105°C to constant weight.
RESULTS AND DISCUSSION
The suitable size and form of litter-trap for
sampling litter-fall in a tropical rain forest is not
known. A study of previous work shows that a
varied size of litter-traps were used. The smallest was 45 x 45 cm (Woodroffe 1982) and the
largest was 200 x 200 cm (Duke et al. 1981).
The form of the trap also shows variation. Mason
(1970) had used round shaped traps instead of
square, and Kira et al. (1967) used a long belt
of plastic net as the trap. In this study a trap
with a square opening measuring 50 x 50 cm
was used. This size is within the range of the
trap used by previous workers, and easy to
handle while in the forest.
Fig. 3.
1 |
Leaf-litter
p^l
Miscellaneous
The pattern of litter fall for 1983 and 1984 in a stand
of Mangrove forest, Siar Beach, Lundu, Sarawak.
The mean values obtained for the mixed
mangrove forest at Siar Beach are 5.74 and 4.49
t/ha/year for total small litter and leaf litter
respectively. These values are significantly lower
than those obtained for many tropical rain forest
(e.g. Nye 1961; Bullock 1973; Gong et al. 1984).
The leaf litter of this forest is about 40% lower
compared to the values obtained for other
mangrove forests. This could be due to the fact
that the mangrove forest at Siar Beach is not as
dense compared to other forests. Such situations
have been highlighted by Gong et al (1984)
for Matang mangrove forest, and Woodroffe
(1982) for Tuff Crater, mangrove forest, Auckland New Zealand. The density of trees at Siar
Beach is 166/ha (Saberi, 1984), and this value
PERTANIKA VOL. 12 NO. 1, 1989
49
SABERI OTHMAN
is about four times lower compared to other forests such as at Banyu Asin, Sumatera (Soekardjo
and Kartawinata 1979), Sabah, Malaysia (Liew
1977) and in Florida, U.S.A. (Pool et al. 1977).
However, there is no data available for comparison on the relationship between density and
litter production in mangrove forests.
Litter production increased in March and
April and reached its highest rate in May. It
subsequently dropped in June, July and August
and remained constant till November. It then
increased again in December and reached its
second peak in February. A similar pattern in
litter fall has been reported for Pasoh (Lim
1978), Matang mangrove forest (Gong et al.
1984) and R. apiculata in Phuket, Thailand
(Christensen and Wium-Anderson, 1977). The
high production in May coincide with high
temperature and draught. Gill and Tomlinson
(1969 & 1971) in their studies of the red mangrove in South Florida, report peak rates of leaf
fall and growth during summer months when
air temperature and incident light were at their
annual peaks. Similar results have been reported
by Heald (1971). Snedaker and Lugo (1973)
found indications that leaf fall increases during
dry periods. According to Lugo and Snedaker
(1975) the timing of these events has a significant interaction with the hydrologic budget and
primary productivity of the forest community.
The higher production in February cannot be
explained in terms of biological processes.
However, its does coincide with heavy winds of
the South China Monsson and rainfall. Occasional storms have been reported to coincide
with increased litter fall (e.g. Pool et al. 1975;
Goulter and Allaway 1979).
Production of litter is relatively continuous, thus supplying the detritus food chain. The
fraction exported to adjacent sea areas is not
known, but many leaves are carried away by
tides, especially at spring tides, before any
degradation takes place.
SABERI OTHMAN
DepartTnent of Biology,
Faculty of Science and Environmental Studies
Universiti Pertanian Malaysia
43400 UPM Serdang Selangor Darul Ehsan,
Malaysia,
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