stem borer of plantation-grown kelampayan in sarawak

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STEM BORER OF PLANTATION-GROWN KELAMPAYAN IN SARAWAK Doreen H.S. Chai 1 *, Marfaisal Marzuki 1 , Het Kaliang 2 and John Sabang 1 SARAWAK FORESTRY Corporation 1 Sarawak Forest Tree Seed Bank, Semengoh, KM 20, Jalan Puncak Borneo, 93250 Kuching, Sarawak, Malaysia 2 Botanical Research Centre, Semengoh, KM 20, Jalan Puncak Borneo, 93250 Kuching, Sarawak, Malaysia *[email protected] Abstract Plantation-grown Kelampayan trees were subjected to serious attacks by stem borer. A study was conducted to evaluate stem borer infestation intensity in Kelampayan plantations in Sarawak. An average of 70% stem borer attacks were found in a few selected local forest plantations. Analyses on the impact of stem borer attack on growth suggested that stem borer attack did not affect the growth performance of Kelampayan trees. Attacks were concentrated at the lower part of the trunk, less than 1 m from the ground level. Intensive silvicultural practice, however, might reduce the susceptibility of stem borer attack. Biological, chemical and silvicultural control and prevention trials are in progress. Keywords: growth performance, intensive silvicultural practice, biological, chemical and silvicultural control. Introduction Establishment of forest plantations is essential to avoid shortage of timber from the natural forests for exportation and to avoid impact of logs as a temporarily solution. In relation to this, Sarawak is targeting in establishing one million hectares of planted forest by the year 2020, which requires an estimate of 30 million seedlings per annum (Anon, 2009). Since 2003, Kelampayan has been introduced as a potential fast growing tree species suitable for forest plantation establishment in Sarawak. To date, 18,851 hectars of Kelampayan were planted, however, Kelampayan plantations declined from 14% in 2007 to 8% among the entire tree species planted. Kelampayan plantations have reported that Kelampayan planted in the field in Sarawak has low survival rate and its growth performance is not as expected. Pest problem in the Kelampayan plantation is widespread especially for stem borers (Marzuki, 2007). Stem borers are economically important, causing degradation of the wood quality and results in the loss of the timber value. Nevertheless, the extent of damage relating to the wood quality, mortality and growth performance has never been determined. The objectives of the present study were to determine the relative importance of the borers by evaluating their infestation intensity in Kelampayan plantations in Sarawak, and to study the control and prevention methods in overcoming stem borer problem in the plantations.

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Page 1: Stem Borer of Plantation-grown Kelampayan in Sarawak

STEM BORER OF PLANTATION-GROWN KELAMPAYAN IN SARAWAK

Doreen H.S. Chai1*, Marfaisal Marzuki1, Het Kaliang2 and John Sabang1

SARAWAK FORESTRY Corporation 1Sarawak Forest Tree Seed Bank, Semengoh, KM 20, Jalan Puncak Borneo, 93250 Kuching, Sarawak, Malaysia

2Botanical Research Centre, Semengoh, KM 20, Jalan Puncak Borneo, 93250 Kuching, Sarawak, Malaysia

*[email protected]

Abstract

Plantation-grown Kelampayan trees were subjected to serious attacks by stem borer. A study

was conducted to evaluate stem borer infestation intensity in Kelampayan plantations in

Sarawak. An average of 70% stem borer attacks were found in a few selected local forest

plantations. Analyses on the impact of stem borer attack on growth suggested that stem borer

attack did not affect the growth performance of Kelampayan trees. Attacks were concentrated at

the lower part of the trunk, less than 1 m from the ground level. Intensive silvicultural practice,

however, might reduce the susceptibility of stem borer attack. Biological, chemical and

silvicultural control and prevention trials are in progress.

Keywords: growth performance, intensive silvicultural practice, biological, chemical and

silvicultural control.

Introduction

Establishment of forest plantations is essential to avoid shortage of timber from the natural

forests for exportation and to avoid impact of logs as a temporarily solution. In relation to this,

Sarawak is targeting in establishing one million hectares of planted forest by the year 2020,

which requires an estimate of 30 million seedlings per annum (Anon, 2009).

Since 2003, Kelampayan has been introduced as a potential fast growing tree species suitable for

forest plantation establishment in Sarawak. To date, 18,851 hectars of Kelampayan were planted,

however, Kelampayan plantations declined from 14% in 2007 to 8% among the entire tree

species planted. Kelampayan plantations have reported that Kelampayan planted in the field in

Sarawak has low survival rate and its growth performance is not as expected. Pest problem in

the Kelampayan plantation is widespread especially for stem borers (Marzuki, 2007). Stem

borers are economically important, causing degradation of the wood quality and results in the

loss of the timber value. Nevertheless, the extent of damage relating to the wood quality,

mortality and growth performance has never been determined.

The objectives of the present study were to determine the relative importance of the borers by

evaluating their infestation intensity in Kelampayan plantations in Sarawak, and to study the

control and prevention methods in overcoming stem borer problem in the plantations.

Page 2: Stem Borer of Plantation-grown Kelampayan in Sarawak

Incidence of Stem Borer Attacks in Kelampayan Plantations and Its Extent of Damage

Inspections were made within the year 2008-2009 at four local forest plantations, selected based

on the plantation scale. Stem borers were common in many plantations, particularly in those

where the young trees had been stressed by weed competition. Our appraisals indicated that

Endoclita sp. was at that time the most widespread of the insect pests present in Kelampayan

plantations (Marzuki, 2007); therefore our studies were largely restricted to this species. Table 1

shows the prevalence of stem borer attacks in Sarawak Kelampayan plantations.

Table 1: Incidence of attacks by the Kelampayan stem borer in Kelampayan plantations in Sarawak

Stand No. of sample plot

Age (year) No. of sample tree Percentage of trees being

attacked (%)

Song 3 (60x25 m) 3-4 63 78

Kanowit I 3 (60x25 m) < 3 96 54

Kanowit II 9 (20x20 m) 1-3 109 63

Kapit I 1 (20x20 m) 2 27 81

In general, high incidences, up to an average of 70% of stem borer attack were detected within

the Kelampayan trees aged 1-4 years. Whereas the pattern of abundance of stem borer was

broadly consistent in most local forest plantations, such consistency was not found in our two

provenance trial plots. The larvae bore at the base of the tree stem, usually less than one meter

from the ground level. The borer attacks were common in those where the trees had been

stressed by grass competition or inappropriate silvicultural practices. From the observation, we

also predict that there is an invariably association between the peak of occurrence and the

difference in seasons, as well as the distribution of the sites.

We also surveyed trees at the age of 1-6 months after planting. From the surveillance, the first

emergent occurred as early as 6 months after planting. However, severe stem borer attacks did

not have a momentous contribution to the high mortality rate of Kelampayan in local forest

plantations.

Cross sections of several Kelampayan trees showing symptoms of attack were made to

determine the extent of wood damage (Figure 1). The tunnels created by the stem borer were

observed to be generally about 15-30 cm deep with diameter of around 1-2 cm. The visual

observation on the cross-section indicates that the wood could still be utilized for reconstituted

wood using technology such as finger jointing (Lai Jiew Kok, pers. comm.).

The sampling data obtained were inadequate to describe the incidence and distribution of the

stem borer attacks in Kelampayan plantations in Sarawak. Nevertheless, certain trends were

reasonably clear, giving the overall notion of the incidence.

Page 3: Stem Borer of Plantation-grown Kelampayan in Sarawak

A B

C D

E F

Figure 1: Symptoms of stem borer attack and the extent of damage. A) Symptom of stem borer with the present of

frass and sap oozing from the entry point. B) Presense of pupal exuvia indicating recent adult emergence. C & D)

Dead Kelampayan tree with its borer attack. E & F) Well-grown Kelampayan tree with multi-attack of stem borer.

Page 4: Stem Borer of Plantation-grown Kelampayan in Sarawak

Analyses of Attacks by Kelampayan Stem Borer

The analyses of attacks were based on Kanowit II Kelampayan stands. Height and diameter at

breast height (DBH) were measured for each sample tree and mean annual increment

(DBH/year) were calculated for each stand. The number of holes bored by stem borers was

recorded for each sample tree. The plot parameters and the number of sample trees are shown

in Table 2. The incidence of the attacks is summarized in Table 3 and Figure 2.

Table 2: Plot parameters and number of samples

Block No. of

sample trees

Age

(month)

Mean Height

(m)

Mean Annual Height

Increment (m)

Mean DBH

(cm)

Mean Annual

DBH Increment

(cm)

2 18 26 (2.2yr) 4.63 2.10 8.24 3.75

6 10 27 (2.3yr) 5.82 2.53 10.02 4.36

7 21 25 (2.1yr) 4.57 2.18 8.02 3.82

10 3 27 (2.3yr) 5.91 2.57 9.30 4.04

11 6 27 (2.3yr) 6.21 2.70 10.58 4.60

12 13 24 (2.0yr) 4.30 2.15 7.23 3.62

15 18 23 (1.9yr) 5.12 2.69 9.72 5.12

18 10 28 (2.3yr) 5.90 2.57 9.93 4.32

40 10 29 (2.4yr) 4.70 1.96 10.04 4.18

Table 3: Data illustrating the degree of attacks exhibited by stem borer in Kanowit II plantation, between the

visits in December 2008 and July 2009

Block No. of attacks per tree % of trees with

Past Present Past Attacks Present Attacks Attacks*

2 1.00 0.60 93.3 40.0 100.0

6 0.20 0.70 20.0 50.0 60.0

7 0.60 0.30 63.2 26.3 79.0

10 0.70 0 66.7 0 66.7

11 1.83 0.20 33.3 16.7 50.0

12 0.33 0.08 33.3 8.3 33.3

15 0.67 0.28 55.6 27.8 72.2

18 1.22 0.11 77.8 11.1 88.9

40 0.63 0 50.0 0 50.0

*Percentage of trees with at least one past and/or one present attack.

Page 5: Stem Borer of Plantation-grown Kelampayan in Sarawak

Figure 2: Percent of trees with symptom of stem borer attack between the field assessments

in December 2008 and July 2009

Attacks of stem borer were observed ranging from 33.3% to 100.0%. The density of past and

present attacks per tree ranged from 0.22-1.83 and 0-0.70, respectively. The data signifies that

multi-entry point per tree is possible (Figure 1E). Stem borer infestation seemed to be peculiar to

certain sites. There was a noticeable decrease of stem borer attacks in July 2009 comparing to

December 2008. Various factors are to be considered: the presence of slashing and clearing

maintenance in the plantation within December 2008 and July 2009 and season distinction

between December (wet season) and July (drought season).

There was no significant correlation between the density of past attacks per year and mean

annual increment (Figure 3), which implies that attack of stem borer did not affect the growth

performance of Kelampayan trees. On the other hand, there seemed to have a fair positive

correlation between the densities of past attacks and the DBH classes. We are in great interest to

comprehend whether as the plantations mature, the stem borer numbers will decline to an

insignificant level. Such information would be beneficial in planning a cost-effective pest

control and prevention regime.

B2 B6 B7 B10 B11 B12 B15 B18 B40

Page 6: Stem Borer of Plantation-grown Kelampayan in Sarawak

Figure 3: Relationship between density of past attacks per year by Endoclita sp. and (LEFT) mean annual height

increment ; (RIGHT) mean annual DBH increment

Figure 4: Difference in density of past attacks by Endoclita sp. among 5 cm DBH classes

DBH Class

No

. o

f p

ast

atta

cks/

tree

Page 7: Stem Borer of Plantation-grown Kelampayan in Sarawak

Pest Susceptibility of Kelampayan under Intensive Management Practices and Its

Implications for control of stem borer

From our survey, most of the Kelampayan plantations in Sarawak do not practice intensive

silvicultural management. It is perhaps not surprising that Kelampayan survival rate is

considerably low as the trees were left to nature after planting and only a minimal care was

taken. According to Stone and Clarke (1998), plantation management requires a holistic multi-

disciplinary approach rather than focusing on a single specific stress such as pest attack.

Focusing on stresses such as weed competition and nutrient deficiencies that are easier to

manage may reduce the potential impact of other stresses such insect attack and weather on

plantation performance (Norris, 1988; Browning 1998).

A recent visit to successful Kelampayan plantation and trial plots in Sabah suggested that

intensive management practice is necessary in maximizing productivity. From the records,

circle weeding, blanket slashing and manuring were conducted quarterly for three years after

planting. Stem borer control were carried out intensively after three years of planting until

harvesting.

Stem Borer Control and Prevention Trials

A few trials were currently carried out in the aim to reduce the susceptibility of pest attacks in

Kelampayan plantations.

Biological control

The weaver ant (Oecophylla smaragdina) has been a promising biological control agent on

mahogany shoot borer (Lim et. Al., 2007). Kelampayan is not listed as host plant for weaver ant

to date and yet considering on possibilities of using weaver ant to reduce stem borer problem in

kelampayan planted forest in Sarawak, a collaborative research work has been initiated.

Surveillance on weaver ants nesting habit and host plants has been conducted since 2008 in few

planted forest and natural forest in Sarawak. More study on conserving and augmenting

existing and relocated colonies are to be initiated. Basically the feeding habits of weaver ant

have yet to be investigated in depth for the prevalence and success of relocated colonies.

Chemical control

A few trial plots were installed to test the effectiveness of insecticides in Kelampayan plantation.

Approximately 10 g of systemic insecticide (carbofuran 3%) was applied into the ground in a

crescent shape on the upper slope of each tree. Monitoring of pest attack and tree growth will be

done every month for up to 6-12 months periods to test the efficacy of the pesticide. In

conjunction with this, we also study the insect pest life cycle as pesticides are generally only

used as required and often only at a specific time in their life cycle.

Page 8: Stem Borer of Plantation-grown Kelampayan in Sarawak

Silvicultural control

A trial site designed to measure benefits of weed control in a 6-month old Kelampayan

plantation was used to test whether young trees benefiting from such silvicultural practices

were more resilient to stress from stem borer damage. Our data obtained in the past 4-months

of monthly circle weeding treatment was insufficient for us to come into any conclusion yet.

However, we expect that, with the knowledge on the seasonal outbreak of this pest, weed

control and other silvicultural practices will accelerate the growth of the trees, therefore

shortening the period of maximum susceptibility to attack.

Conclusion

Surveys of Kelampayan stem borer during the past two years, and current studies in Kanowit II

Kelampayan plantation, permit certain generalizations concerning the incidence of stem borer

attack in Sarawak to be made.

The evidence presented in this paper suggests that Endoclita sp. is rarely the cause of significant

loss of growth increment or high mortality rate of Kelampayan. The use of silvicultural

practices known to promote tree vigour which also reduce the susceptibility of attack is to be

considered. Together with the knowledge in site characteristics and associated tree growth,

these practices can be tailored to improve cost efficiency and to maximize productivity.

Acknowledgements

Empenit Empawi and Lily Encharang assisted in surveillance and trials. We also thank the

commercial plantation agencies, and others who were involved to make this study successful.

References

Anon. 2009. Seminar to boost forest plantation activities. Sarawak Timber Association Review 188 :

2

Browning, J.A. 1998. One phytopathologist’s growth through IPM to holistic plant health: The

key to approaching genetic yield potential. Annual Review of Phytopathology 36: 1-24

Lim, G.T., Kirton, L.G., Ariffin, S., Salom, S. M., Kok, L.T. and Pfeiffer, D.G. 2007. Partnering the

weaver ant to control the mahogany shoot borer in peninsular Malaysia. Applied Forest

Science Research Seminar 2007. Catalysing Planted Forest Development and Biodiversity

Conservation. Wisma STA, Kuching, Sarawak. 1-2 November 2007

Page 9: Stem Borer of Plantation-grown Kelampayan in Sarawak

Marzuki, M. 2007. Endoclita aroura Tindale: Stem Borer of Kelampayan Species. Applied Forest

Science Research Seminar 2007. Catalysing Planted Forest Development and Biodiversity

Conservation. Wisma STA, Kuching, Sarawak. 1-2 November 2007

Norris, D.M. 1988. Sensitivity of insect-damaged plants to environmental stresses. In: Heinrichs,

E.A. (ed.). Plant Stress-Insect Interactions. John Wiley and Sons, New York

Stone, C. and Clarke, A.R. 1998. A phytocentric approach towards future pest management in

Australia eucalypt plantations – an alternative to classical IPM. In: Zalucki, M.P., Drew,

R.A.I. and White, G.G. (eds). Pest Management – Future Challenges. Proceedings of Sixth

Australasia Applied Entomological Research Conference. Brisbane, Australia, 29

September – 2 October 1998. Pp. 144-152