SURVEYS FOR STEM CANKER AND STEM BORER OF DURIAN IN THE COASTAL AREAS OF CAMBODIA

Kim Eang. Tho1, R.T. Baconguis, A.D. Raymundo, T.U. Dalisay

1 Bsc. in Agriculture (major in: Plant Pathology, minor in: Extension Education) Royal University of Agriculture (RUA), Cambodia.

HIGHLIGHT OF WORLD PRODUCTION OF DURIAN

World production of durian is concentrated in wet tropical Southeast Asia and Australia.

Country Area planted (ha) Production (t) Value (USD ’000)

Thailand 138,024 927,200 2,686,000

Malaysia 106,860 200,000 1,020,000

Vietnam 40,000 110,000 330,000

Indonesia 36,024 200,000 780,000

Philippines 8000 145,000 522,000

Table 1. Production of durian in selected countries in Southeast Asia (Source: Drenth & Sendall, 2004)

DURIAN PRODUCTION IN CAMBODIA

Durian production areas

• major durian production locates in the coastal areas.• about 1000 ha • most are small (backyard), and medium cultivations

DURIAN PRODUCTION IN CAMBODIA

Stem Canker and Stem Borer Problems

Stem Canker (P. palmivora Bult.)

Stem Borer (B. rufomaculata De Geer)

Death of trees after 4 to 5 years

PARTICIPATORY RESEARCH AND DEVELOPMENT

Dr. Robert Chambers

He is the author of several influential development books and journals. He is also credited for leading the way to a methodological revolution of values, approaches, behavioursand methods, collectively called Participatory Rural Appraisal (PRA).

EFFECTIVE PEST CONTROL SHOULD BE DONE BY:

Farmers

Extension workersResearchers

Biological Sciences of plant pathology

Social Sciences and Arts of Plant

Pathology

OBJECTIVES OF THE RESEARCH

To determine the occurrence of stem canker and stem borer and their current situations in the coastal areas of Cambodia

To identify farmers and local authority’ problems and needs related to durian pest controls.

To draft out the project planning for the community

FIELD SURVEY

Locations of the studied areas (represented in star-points): Teuk Chhou District, Kampot City and Kep Province

- Surveys for the incidence of stem canker and stem borer were conducted in the coastal areas of Cambodia from May to July 2010, using symptomatology- 300 trees [100 per location; (4 replications; 25 tree per replication)].- % incidence = Number of infected trees/total number of surveyed trees x 100

DISEASE SEVERITY

-Measuring disease severity was done by using the rate of canker severity (Aderson & Guest, 1990):

- 0 : no canker- 1: canker < 100 Cm2- 2: canker > 100 Cm2 but < 70% of girdling of the main trunk- 3: canker > 70% girdling of the main trunk/ almost dead owing to canker

INCIDENCE OF STEM BORER

Observation of stem borer incidence

Larva (8-10 Cm in length)

Larva makes deep tunnel into heartwood

ISOLATION OF THE PATHOGEN

- Infected barks and leaves were collected.- Isolation of the pathogen was done using the method described in (Drenthand Sendall, 2004), with some modifications.

RESULTS

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

Teuk Chhou Kampot Kep Total

HealthyWith disease

P. palmivora disease incidence in Teuk Chhou, Kampot and Keb

RESULTS

0%

5%

10%

15%

20%

25%

30%

35%

40%

Teuk Chhou Kampot Kep Total

Score 0Score 1Score 2Score 3

- 0 : no canker- 1: canker < 100 Cm2- 2: canker > 100 Cm2 but < 70% of girdling of the main trunk- 3: canker > 70% girdling of the main trunk/ almost dead owing to canker

RESULTS

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

Teuk Chhou Kampot Kep Total

No stem borerAttacked by stem borer

Incidence of Stem borer

RESULTS

There is a positive relationship between disease severity and age of durian (r = 0.313); Y = 0.36 + 0.39X [Y: disease severity; X: age of durian].

LOGISTIC REGRESSION OF STEM BORER - (WITH AGE OF PLANT AND DISEASE SEVERITY)

Stem borer tended to attack trees affected by stress or stem canker. Y = 1.38X1 – 0.1X2 – 3.4 (R2= 0.24); [Y: stem borer incidence; X1: stem canker severity; X2: age of durian]

50 µm

Typical P. palmivora sporangia: papillate, caducos and with a short pedicel; non-septated mycelia; scale bar = 50 µm.

Structure Measurementa

Sporangia

Length (µm) 57.35 ± 5.18

Breadth (µm) 37.21 ± 4.79

L/B ratio 1.56 ± 0.16

Table 7. Characteristic of isolates of P. palmivora from durian

aMean ± standard deviation; (n= 60)

Frequency distribution of sporangia length (µm) of P. palmivora isolates from durian in the coastal

areas of Cambodia

Frequency distribution of sporangia breadth (µm) of P. palmivora isolates from durian in the coastal

areas of Cambodia

Frequency distribution of sporangia length/breadth ratio of P. palmivora isolates from durian in the

coastal areas of Cambodia

IDENTIFY THE PROBLEMS IN DURIAN PEST MANAGEMENT

FGD with local farmers PRA tools with local farmers

Discussion with key informants Reflection and feed back from national researchers and developers

GENERAL VIEW OF THE PROBLEMS

Both farmers and extension workers have lack of knowledge in pest controls.

Low available extension programs. Low available capital to invest and establish

effective controls of these pests. Price competition from imported fruits also

contributes to lower durian production and its pest controls.

PROJECT PLANNING FOR THE COMMUNITY

Problem Analysis

Methods Tools and techniques Outcomes

PRA, FGD, SWOT… etc.

Problem tree

Need assessments

Objective tree

Criteria analysisPrioritized problems

and objectives

Project development (Logframe, Activity and Budget planning)

Famers and LA

Famers and LA

Workshop and pers.com

Famers, LA

Researchers and developers

Farmers

Extension workersResearchers

Project development (Logframe, Activity and Budget planning)

IMPLICATIONS OF PEST CONTROLS

Integrated pest management in both stem canker and stem borer for more effective controls.

Establish effective extension programs for both farmers and training of trainers in pest controls.

Establish the programs to support quality seedlings production and disease eradication.

Establish of durian production community

FUTURE STUDIES

1. On farm-trials of integrated pest control measures; comparison between [sanitary, water management, soil fertility management, phosphonate injection, organic mulching, stem borer inspection and killing…etc] vs. conventional practice.

2. Yield loss assessment and cost-benefit analysis.

3. Morphological, cultural and genetic variations of P. palmivora in the areas.

ACKNOWLEDGEMENTS

Australian Crawford Funding and the Australian AusAid Program for their sponsorship to attend the 2011 APPS conference.

ACIAR for funding the research through Cambodian Agricultural Research Fund (CARF).

University of the Philippines Los Baños (UPLB) for comments and advices.

Dr. Benjamin Stodart, Chales Sturt University (CSU), Australia for advices and nomination.

Royal University of Agriculture (RUA) and General Department of Agriculture (GDA), Cambodia for their collaboration.