Serangga20(1): 43-53
ISSN 1394-5130 © 2015, Centre for Insects Systematic,
Universiti Kebangsaan Malaysia
BUNCH MOTH, TIRATHABA RUFIVENA
(LEPIDOPTERA: PYRALIDAE) INFESTATION CENSUS
FROM OIL PALM PLANTATION ON PEAT SOIL IN
SARAWAK
Zulkefli Masijan, Norman Kamarudin, Ramle Moslim,
Alindra Gerald Sintik, Siti Nurul Hidayah Ahmad and Siti
Ramlah Ahmad Ali
Biological Research Division, Malaysian Palm Oil Board, No. 6, Persiaran
Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor
Corresponding email: zulmas@mpob.gov.my
ABSTRACT
Tirathaba rufivena is the major pest in oil palm plantation
planted in peat soil in Sarawak. High infestation was reported in
Miri, Mukah and Sibu. Censuses on the infestation of T.
rufivena were conducted at three different locations, i.e. in Miri
(young palm), Mukah (mature palm) and Sibu (ablation
samples). Samples for census were taken from infested bunches,
female and male inflorescences. The census was done by
chopping the bunches and the female inflorescences while for
the male inflorescences, the bottom of spikelets were cut to
determine the number of live larvae and pupae. The census
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reveiled that in Sibu, a high infestation of T. rufivena was found
on male inflorescences compared to bunches of female
inflorescences. The mean number of live larvae found in male
inflorescences for the first and second day of census recorded
35.3 ± 15.7 and 14.0 ± 7.3, respectively. The highest number of
live larvae recorded from male inflorescences was 207 and 65,
respectively. Meanwhile, the mean number of live larvae from
infested bunches and female inflorescences on the first day were
9.9 ± 3.5 and 19.4 ± 4.4, respectively. On the second day of
census, the mean number of live larvae recorded on bunches and
female inflorescences were 4.8 ± 1.5 and 12.7 ± 2.8,
respectively. Census on infested area in Miri from three
different stages of female inflorescence and bunches recorded
8.0 ± 1.9 and 4.8 ± 0.6 highest number of live larvae. Post
anthesis female inflorescences recorded the highest mean
number of live larvae compared to pre anthesis and anthesising
female inflorescences. Population study at Mukah on highly
infested area recorded 60 live larvae from young bunches and
50 live larvae from matured female inflorescences. Based on the
samples, bunch moth larvae or pupae were absent in 10% of
infested female inflorescences and 11.7% of infested bunches
(males and females inflorescences).
Keywords: Tirathaba rufivena, bunch moth, oil palm
inflorescences, peat soil.
ABSTRAK
Tirathaba rufivena merupakan perosak yang penting yang
menyerang tanaman kelapa sawit tanah gambut di Sarawak.
Kadar infestasi yang serius dicatat di Miri, Mukah dan Sibu.
Pembancian terhadap penginfestasian oleh T. rufivena
dijalankan di tiga lokasi yang berbeza-beza iaitu, di Miri (palma
Zulkefli Masijan et al
45
muda), Mukah (palma matang) dan Sibu (palma ablasi). Sampel
bunga jantan dan betina diambil daripada tandan yang
berpenyakit. Bancian dijalankan dengan mencantas tandan dan
bunga betina manakala dasar spikelet dikerat dari spesimen
bunga jantan untuk mengenalpasti bilangan larva dan pupa yang
hidup. Infestasi T. rufivena paling tinggi pada bunga jantan
berbanding bunga betina di Sibu. Purata larva yang hidup pada
bunga jantan pada hari pertama dan kedua ialah 35.3 ± 15.7 dan
14.0 ± 7.3. Bilangan larva hidup pada bunga betina yang paling
tinggi direkodkan adalah sebanyak 207 dan 65. Manakala,
purata bilangan larva yang hidup yang menginfestasi tandan dan
bunga betina pada hari pertama ialah 9.9 ± 3.5 dan 19.4 ± 4.4.
Pada hari kedua pula, purata bilangan larva yang hidup pada
tandan dan bunga betina ialah 4.8 ± 1.5 dan 12.7 ± 2.8. Bancian
di kawasan yang mengalami infestasi di Miri dari 3 fasa yang
berbeza mencatat bacaan larva yang hidup pada tandan dan
bunga betina yang tertinggi sebanyak 8.0 ± 1.9 and 4.8 ± 0.6.
Bunga betina selepas fasa antesis mencatat purata bilangan larva
hidup yang paling tinggi berbanding sebelum fasa antesis dan
bunga betina yang sedang antesis. Kajian populasi di kawasan
dengan infestasi paling teruk di Mukah dengan catatan 60 larva
yang hidup daripada pokok yang muda dan 50 larva daripada
pokok betina matang. Berdasarkan sampel, larva dan pupa tiada
pada 10% bunga betina yang terinfestasi dan 11.7 % bunga
jantan dan betina yang terinfestasi.
Kata kunci: Tirathaba rufivena, kupu-kupu, kelapa sawit tanah
gambut.
INTRODUCTION
Tirathaba rufivena (Lepidoptera: Pyralidae) or commonly
known as oil palm bunch moth is occasional pest of oil palm
that seriously attacks the fresh fruit bunches especially in areas
where the pollination is poor (Basri et al, 2003). The infestation
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of oil palm bunch moth is characterized by the presence of long
tubes of silk and frass constructed by the larvae. The larvae feed
on both male and female inflorenscences of oil palm (Wood and
Ng, 1974; Turner and Gillbanks, 2003). The life cycle of the
pest is short, about 30 days (eggs 4 days, larvae 16 days and
pupae 10 days), and therefore it spreads rapidly (Lim, 2012).
The female lays eggs, either singly or in batches of 4 to 20 in
the fibrous sheath surrounding the base of the flower spike
(Khoo et al., 1991).
Infestation of bunch moth causes abortion to young
inflorescences female flowers, fruit bunches and may cause fruit
deformation (Basri et al., 1991). A visual inspection on the
infested bunches and the percentage of the infested palms could
not represent the actual bunch moth population in the infested
area. Therefore, the infested bunches should be harvested and
chopped to count the actual number of live larvae and pupae
(Zulkefli et al., 2012).
High infestation of bunch moth was reported in oil palm
planted on peat soil in Mukah, Sibu and Miri in Sarawak during
the rainy season. The common suggestion for bunch moth
control is by using Bacillus thuriengiensis, cyfluthrin and
diflubenzuron (Basri et al., 1991). Various insecticides have
been used to control the bunch moth but these chemicals are
hazardous to beneficial insects such as pollinating weevil
Elaeidobius kamerunicus, parasitoids and predators.
MATERIALS AND METHODS
Bunch moth populations were studied at three different
locations in Sarawak based on the methods described by
Zulkefli et al. (2012). Because of time constrains, the sampling
periods were not done the same time however, most of them
were conducted at the end of the year during high rainfall while
one sampling conducted during dry period.
Samples of male inflorescences (post anthesis - moist),
female inflorescences (post anthesis) and young bunches with
Siti et al.
47
fresh frass (moist and reddish) were selected from the infested
oil palm plantation. These visual inspections served as the basic
indicator of the infestation stage before the actual counts of
larvae on the specific samples were conducted. Samples of male
inflorescences were only included during the census at Sibu
because on a few observations a high population of early stages
was detected on the post anthesis spikelets. Each male
inflorescence was cut at the bottom of the spikelet to facilitate
the collecting and counting of bunch moth larvae on aluminium
tray. Each larva was sorted to its stage of development.
The female inflorescences and young bunches (<I
month) were collected from the infested area. Samples with less
frass and damage on the fruit surface were eliminated from the
sampling. In the areas where the infestation was low, shiny
fruitlets gave indication that the number of live bunch moth
larvae in the samples would also be low. Later, the samples
were chopped to determine the live bunch moth larvae and
pupae. All the inflorescences or fruitlets were placed on the
aluminium trays to facilitate the collecting and finding of the
live larvae and pupae. Care was taken to check at the bottom of
each fruitlet or flower.
The first sampling was conducted in Miri, Sarawak.
Sampling was conducted on 18 month- old palms planted on
peat soil. This area was chosen because no treatment to control
the bunch moth was done in the area. Three developmental
stages of female inflorescences (pre, at and post anthesis) and
young bunches were selected for the study. The same
procedures as mentioned above were applied to determine the
bunch moth population.
The second sampling was conducted at Mukah,
Sarawak. The sampling was conducted on 5 year-old palms at
five different plots. In each plot, four female inflorescences and
twelve bunches were selected to determine the levels of
infestation. A total of 20 female inflorescences and 60 young
bunches were selected to determine the bunch moth population
in the area.
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The final sampling was conducted in Sibu, Sarawak on
young palms from ablation carried out by the plantation.
Bunches, female and male inflorescences were collected. Two
censuses were conducted during the sampling. The first census
was carried out on the first day of ablation, and the second
census on samples of second day after ablation which were left
by the road side. The same procedures were applied in
determining the infestation number of bunch moth larvae.
RESULTS AND DISCUSSION
Census on three different stages of female inflorescences and
young bunches in Miri, Sarawak recorded the highest mean
number of live bunch moth larvae found on post anthesis female
inflorescences, with mean number of 8.0 ± 1.91 (Table 1). The
mean number of live bunch moth larvae on young bunches
recorded was 4.79 ± 0.55 (Table 1).
Table 1. Mean live bunch moth larvae from infested female
inflorescences and bunches from 18 months old palm in Miri,
Sarawak
Inflorescencestage
Pre - anthesis
Anthesising
Post - anthesis
Bunch
n
17
16
14
70
Live bunch moth
larvae
Mean ± SE
5.20 ± 1.35
7.56 ± 1.97
8.0 ± 1.91
4.79 ± 0.55
Range
0 - 23
0 - 27
1 - 21
0 - 18
Population study at Mukah on highly infested area recorded 60
live larvae as the highest number of live bunch moth larvae
from young bunch and 50 live larvae from female
inflorescences (Table 2). High numbers of live bunch moth
larvae were detected from young bunches in plots 2 and 4.
Zulkefli Masijan et al.
49
Based on 80 samples, 10% of infested female inflorescences
and 11.7% of infested bunches were absent of bunch moth
larvae. Two days of census on ablation bunches and
inflorescences recorded high number of bunch moth larvae on
male inflorescences. A total of 207 live bunch moth larvae were
recorded as the highest number from 23 samples (Tables3 and
4). Census at Sibu, Sarawak showed that the highest infestation
number of T. rufivena found in male inflorescences at both first
and second day of ablated samples with mean densities were
35.3 ± 15.7 (Table 3) and 14.0 ± 7.3 (Table 4).The number of
live larvae found in male inflorescences ranged from 1 – 207
per inflorescence (Table 4) and 0 – 65 per inflorescence (Table
4). The infested bunches and female inflorescences on the first
day recorded the mean density of 9.9± 3.5 and 19.4 ± 4.4,
respectively.
On the second day of ablation, samples of infested
female inflorescences still had a high infestation with bunch
moth larvae recording the mean density of 12.7 ± 2.8 with the
live larvae ranging from 3 – 34 per inflorescence (Table 4).
Meanwhile, lower infestation number was found on bunches
with the mean density of 4.8 ± 1.5 and live larvae ranging from
0 – 15 per bunch (Table 4).
Table 2. Mean live bunch moth larvae from infested female inflorescences and bunches from Mukah,
Sarawak.
Female inflorescence
Young Bunch
Location
Plot 1
Plot 2
Plot 3
Plot 4
Plot 5
n
4
4
4
4
4
Mean ± SE
27.0 ± 8.93
18.75 ± 6.29
6.50 ± 4.63
11.25 ± 6.03
25.25 ± 10.30
Range
11 - 49
0 - 27
0 - 20
2 - 29
1 - 50
n
12
12
12
12
12
Mean ± SE
12.25 ± 2.99
21.25 ± 5.06
6.08 ± 2.09
18.50 ± 5.37
12.50 ± 3.67
Range
0 - 35
2 - 60
0 - 22
0 - 60
0 - 41
Zulkefli Masijan et al.
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Table 3 Mean live bunch moth larvae on day one at Sibu,
Sarawak (ablation).
Source
Female
inflorescence
Male
inflorescence
Bunch
n
Live bunch moth
larvae
Mean ± SE
13
19.4 ± 4.4
Range
0 – 39
12
35.3 ± 15.7
1 – 207
10
9.9 ± 3.5
1 – 30
Table 4 Mean live bunch moth larvae on day two at Sibu,
Sarawak (ablation).
Source
Female
inflorescence
Male
inflorescence
Bunch
n
Live bunch moth
larvae
Mean ± SE
10
12.7 ± 2.8
Range
3 – 34
10
14.0 ± 7.3
0 – 65
12
4.8 ± 1.5
0 – 15
CONCLUSION
Early detection and regular census are important to prevent
severe infestation of T. rufivena. Once the pest has established
infestation, various stages of development of the palm will be
attacked. Visual observation of infested bunches, based on
pitted fruitlets and bunches covered with fresh frass, sometimes
does not reflect the actual number of live larvae of bunch moth.
A high number of early stage bunch moth larvae were detected
on post anthesis male inflorescences. The current practice does
not consider the male inflorescences in the management of
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bunch moth; this may have to change. The common method is
to treat the female inflorescences and the infested bunches only.
Selective treatment is recommended at this stage because the
male flowers also harbours the breeding sites for the pollinating
weevil. Treatment with biological agents (i.e. Bacillus
thuringiensis) is needed to control the population especially at
the early stage.
Good sanitation practices are important in reducing the
bunch moth infestation. The census done at Sibu has shown that
the infestation number of live T. rufivena was still high even
after two days of leaving the infested materials along the road
side. Infested bunches, male and female inflorescences should
be destroyed to reduce the infestation. Reducing their breeding
sites will correspondingly reduce their chances of infesting new
inflorescences that will eventually lead to abortive bunches.
ACKNOWLEDGEMENTS
The authors wish to thank the Director- General of MPOB,
Datuk Dr. Choo Yuen May for her permission to publish this
paper. They also would like to thank the Entomology staff at
MPOB Lahad Datu, MPOB Research Station Sessang and Mr
Siaw Ting Chuan for their assistance in conducting this study.
Finally, to the managers of Tinbarap 9 Estate, Zumida Estate
and Ta Ann Pelita Igan, Sarawak for permission to conduct this
study in their plantations.
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