OBJECTIVE
The objective of this study is to spatially identify the pattern of BSR disease under natural field epidemic by using nearest-neighbor analysis (NNA).
REFERENCES
Azahar, T. M., Jawahir Che Mustapha, Mazliham, S. and Patrice Boursier. 2011. Temporal Analysis of Basal Stem Rot Disease in Oil Palm Plantations: An Analysis on Peat Soil. International Journal of Engineering & Technology IJET-IJENS 11(3): 96-101
Idris, A. S. 2012. Ganoderma disease of oil palm in Malaysia: Latest technologies on detection, control and management. Paper presented at 17th International Conference on Oil Palm and Expopalma, 25-28 September 2012, Convention Centre, Cartagena De Indias, Colombia
Idris, A. S., Mior, M. H. A. Z., Maizatul, S. M. and Kushairi, A. 2011. Survey on status of Ganoderma disease of oil palm in Malaysia 2009-2010. Proceedings of the PIPOC 2011 International Palm Oil Congress. Kuala Lumpur Convention Center, Malaysia, 15-7 November 2011 235-238 Madden, L. V., Louie, R., Abt, J. J. and Knoke, J. K. 1982. Evaluation of tests for randomness of infected plants. Phytopathology 72: 195-198
Mior Mohd Hadafi, A. Z., Idris, A. S., Wahid, O. and Ahmad Kushairi, D. 2009. Spatial, temporal, and hot spot analysis of Basal Stem Rot disease caused by Ganoderma in oil palm planted on inland soil at Kluang, Johor. Proceedings of the PIPOC 2009 International Palm Oil Congress (Agriculture, Biotechnology, Sustainability). Organizer, place, and date: 1371-1382 (not complete)
Reesa, R. W., Flood, J., Hasan, Y., Potter, U. and Cooper, R. M. 2009. Basal stem rot of oil palm (Elaeis guineensis): mode of root infection and lower stem invasion by Ganoderma boninense. Plant Pathology 58: 982-989 Suriya Rao, A. V., Mukherjee, A. K., Mohapatra, N. K. and Nayak, P. 2007. Spatial Distribution of Rice Blast Disease under Natural Field Epidemics. Research Journal of Agriculture and Biological Sciences 3(6): 615-620
1
Assis Kamu,
1Chong Khim Phin,
2Idris Abu Seman,
3Hoong Hak Wan,
1Ho Chong Mun
1Faculty of Science and Natural Resource, Universiti Malaysia Sabah, UMS Road, 88400 Kota Kinabalu, Sabah, MALAYSIA
2GANODROP Unit, Malaysian Palm Oil Board, 6, Persiaran Institusi Bandar Baru Bangi, 43000, Kajang, Selangor, MALAYSIA
3Sawit Kinabalu Bhd, Jalan Kelapa Sawit, off km 4, Jalan Tuaran, 88300 Kota Kinabalu, Sabah, MALAYSIA Corresponding author’s email: [email protected]
RESULTS
SPATIAL STATISTICAL ANALYSIS OF GANODERMA BASAL STEM ROOT DISEASE UNDER NATURAL FIELD EPIDEMIC OF OIL PALM
INTRODUCTION
Oil palm is a golden crop of Malaysia with revenue of RM70 billion generated from varieties of palm oil based products (MPOB, 2013). The industry is well-established but yet facing with some problems arise lately.
Two of the major problems in terms of productivity are lack of manpower and the presence of incurable oil palm disease, the Basal Stem Rot (BSR) caused by Ganoderma boninense. Basal Stem Rot (BSR) remains the most important disease, present in more than 50% of the oil palm fields in Malaysia (Idris et al., 2011). BSR disease is the most widely studied and knowledge available of oil palm disease in Malaysia (Idris, 2012). But there is still limited study on the spatial as well as temporal pattern or distribution of the disease especially under natural field epidemic condition in oil palm plantation (Azahar et al., 2011).
METHOD
Study sites: MBE0702, SKE0224 & MDE8918 (Different in year of planting) Disease detection method: Based on external visible disease symptoms (Idris, 2012)
Date of BSR census: April 2014 (SKE0224), June 2014 (MBE0702), August 2014 (MDE8918)
Spatial statistical analysis: Nearest-neighbor analysis (NNA)
0 5 10 15 20 25 30 35 40 45 50
0 10 20 30 40 50 60 70
Meter x 10
Meter x 10
MBE0702
0 5 10 15 20 25 30 35 40 45
0 10 20 30 40 50 60 70
Meter x 10
Meter x 10
SKE0224
0 5 10 15 20 25 30 35
0 10 20 30 40 50 60 70 80
Meter x 10
Meter x 10
MDE8918
MBE0702 SKE0224 MDE8918
Points analysed: 202 99 256
Average NN Distance (Observed): 1.54 1.95 1.53
Average CSR Distance (Expected): 1.75 2.39 1.46
Variance CSR Distance: 0.0041 0.0158 0.0023
Distribution z-score (+/- 1.96 @ 0.05): -3.28 -3.42 1.44
Clark Evan's R 0.8793 0.8200 1.0471
Clark Evan's c-score (+/- 1.96 @ 0.05): -3.7914 -3.8375 0.4979
Reflexive pairs: 56 31 69
DISCUSSION
Table shows the results of the statistical test on the NNI. This test is used to test the null hypothesis that the events or spatial pattern exhibit CSR. The results show that there is a mixed result. The average NN distance of MBE0702 and SKE0224 is lower than its average CSR distance which means the spatial distribution of the infected palms at both study sites is not random. But for MDE8918, it shows an evidence of complete spatial randomness of BSR disease at 5% level of significance. The findings of MDE8918 is contradict with the fact that the primary route of infection of BSR disease appears to be through root contact with inoculum sources in the soil (Rees et al., 2009). But this supports the findings of Mior Mohd Hanafi et al. (2009) where they found the incidence of BSR at Kluang, Johor throughout 13 years was random and was not a function of time of infection.
CONCLUSION
Identification of the type of disease pattern and spread in a field is critical in epidemiological investigations. It can help the authorities in selecting a strategy to combat the outbreak. A random pattern of infected plants suggest that, at the time of observation, the pathogen is not spreading from plant to plant. Conversely, aggregations (clusters) of infected plants suggest that the pathogen is spreading from plant to plant within a field (Madden et al., 1982; Suriya Rao et al., 2007). Spatial pattern of any soil born disease like BSR disease is very critical to be identified as this could help the stakeholder in identifying the best method to control the outbreak of the disease. This study has identified that the mode of infection of BSR disease could be from plant to plant (since the spatial distribution is not random at MBE0702 and SKE0224) or could be by spore (since the spatial distribution of MDE8918 is random). However, there are many factors such as different spatial statistical test, planting density, topography as well as management factor need to be considered to confirm the spatial pattern of BSR disease.
By considering all these factors, it would give a better understanding on the spatial pattern of BSR disease.
ACKNOWLEDGEMENT
We would like to acknowledge Malaysia Palm Oil Board (MPOB) for funding this project and also Sawit Kinabalu Sdn Bhd for allowing us to conduct the study in their selected oil palm estates in Tawau, Sabah.
OUTCOME
Student – 1 PhD student (on going)
Conference – 1 paper presented at the 2nd ISM International Statistical Conference 2014 with Applications in Sciences and Engineering (ISM-II), MS Garden Hotel, Kuantan Pahang, 12-14 August 2014
Publication - ISM-II Proceedings by the American Institute of Physics (AIP). Indexed in SCOPUS and ISI
