Life expectancy of oil palm (Elaeis guineensis) infected by Ganoderma boninense in coastal soils,Malaysia: a case study

Ganoderma boninense basal stem rot poses a serious threat to the oil palm industry. The effects of external disease symptoms and coastal soils (Briah – Typic Endoaquepts, Jawa – Typic Sulfaquepts, and Selangor – Typic Humaquepts) on the life expectancy of the infected palms, from disease detection to death, were studied. Six-monthly censuses on disease classes for each palm were recorded between 2004 and 2012. Survival curves of disease symptoms and soil types were compared using Kaplan–Meier and log-rank methods, respectively. Ganoderma-infected palms in acid-sulphate (AS) and potential AS soils recorded lower life expectancy. Survival duration of infected palms with foliar symptoms was 12-months shorter. External factors, such as soil type may influence the survival of infected palms and soil types may pre-dispose oil palm to higher risk of Ganoderma infection. More effective Ganoderma management for palms planted on Coastal soils (with and without AS layer) have been proposed.     

Identification of <Emphasis Type="Italic">Ganoderma</Emphasis>, the causal agent of basal stem rot disease in oil palm using a molecular method

From comparison of the alignments of the internally transcribed spacers (ITS) of ribosomal DNA from Ganoderma associated with oil palm basal stem rot (BSR) and other Ganoderma species, two specific primer pairs were selected to provide a specific DNA amplification of pathogenic Ganoderma in oil palm. Each primer pair produced a single PCR product of about 450 bp (for primer pair IT1–IT2) and 334 bp (for primer pair IT1–IT3) when oil palm Ganoderma DNA was used. No PCR amplification product was observed when other Ganoderma species DNA was used in PCR amplification with these primer pairs. Three specific restriction enzyme sites were identified in the ITS and intergenic spacer (IGS1) regions. The restriction enzymes MluI, SacI and HinfI were used to digest the ITS-PCR product and restriction enzymes TfiI, ScaI and HincII were used to digest the IGS1-PCR product. Of the three restriction enzymes used in each rDNA region, MluI specifically digested the ITS regions, and TfiI specifically digested the IGS1 region of oil palm Ganoderma. Analysis of the published ITS nucleotide sequences of 31 Ganoderma species showed that the MluI restriction site was not present in other Ganoderma species. The use of both specific primers and restriction enzyme analysis can be applied as a standard protocol to identify pathogenic Ganoderma in oil palm. In this study, the use of specific primers and PCR-RFLP analyses of the rDNA gave consistent results for the characterisation of pathogenic Ganoderma, and indicated that Ganoderma strains associated with BSR disease in oil palms belong to a single species.     

Development and evaluation of an enzyme-linked immunosorbent assay (ELISA) and dot immunobinding assay (DIBA) for the detection of Ganoderma infecting palms

The genus Ganoderma has a worldwide distribution causing root and stem rot of many plantation crops. A limiting factor in controlling the BSR disease is the lack of reliable diagnostic method(s) for early diagnosis. In this study, we developed polyclonal antiserum for Ganoderma mycelial and extracellular protein, and evaluated its efficacy with different plant samples collected from artificially inoculated coconut seedlings and Ganoderma infected field palms. We also tested the cross-reactivity with the soil-borne and saprophytic fungus collected from different parts of coconut palm. The antisera developed against the crude mycelial protein (CMP) and extracellular protein (ECP) showed a 1:1000 titre value for the detection of Ganoderma. The CMP antisera developed showed more cross-reaction when compared to ECP antisera of Ganoderma. In the DIBA test, at a 1:10 dilution of antigen, 1:1000 dilution of CMP and ECP antisera, 1:5000 dilution of secondary antibody gave clear distinctions in colour development between healthy and diseased samples. In the DIBA test, ECP antisera detected positive control (ECP of Ganoderma MTP and CRS-1 isolate), artificially inoculated roots, infected field roots, infected basal trunk and additionally lesions gave positive reactions which were not found in the CMP antisera tested. Therefore, both ELISA and DIBA tests may be useful for screening a large number of samples and help in the detection of infection at the earliest stage of disease development and this will certainly help to adopt suitable management strategies against Ganoderma disease in palm crops in advance.     

Following basal stem rot in young oil palm plantings

The PCR primer GanET has previously been shown to be suitable for the specific amplification of DNA from Ganoderma boninense. A DNA extraction and PCR method has been developed that allows for the amplification of the G. boninense DNA from environmental samples of oil palm tissue. The GanET primer reaction was used in conjunction with a palm-sampling programme to investigate the possible infection of young palms through cut frond base surfaces. Ganoderma DNA was detected in frond base material at a greater frequency than would be expected by comparison with current infection levels. Comparisons are made between the height of the frond base infected, the number of frond bases infected, and subsequent development of basal stem rot. The preliminary results suggest that the development of basal stem rot may be more likely to occur when young lower frond bases are infected.     

Molecular biology of <Emphasis Type="Italic">Ganoderma</Emphasis> pathogenicity and diagnosis in coconut seedlings

The pathogenicity of Ganoderma boninense was tested on coconut seedlings under greenhouse conditions and infection confirmed by using immunological and molecular diagnostic tools. Desiccation of older leaves and the emergence of sporophores were observed from pathogen-inoculated seedlings, whereas a control seedling does not show any pathogenic symptoms. Mature sporophores were formed within 10–13 weeks after inoculation. Polyclonal antibodies raised against mycelial proteins of Ganoderma were used for detection of Ganoderma in infected field palm and seedlings through indirect enzyme-linked immunosorbent assay technique. We adopted dot-immunobinding assay for the detection of Ganoderma from greenhouse and field samples. Under nucleic-acid-based diagnosis, G. boninense (167 bp) was detected from artificially inoculated seedlings and infected field palms by polymerase chain reaction. Apart from these, histopathological studies also support the Ganoderma pathogenicity in coconut seedlings. The pathogenicity test and combination of all the three diagnostic methods for Ganoderma could be highly reliable, rapid, sensitive and effective screening of resistance in planting material in the future.     

Local and landscape drivers of arthropod diversity and decomposition processes in oil palm leaf axils

相似文献   

A review of the ecosystem functions in oil palm plantations,using forests as a reference system

Oil palm plantations have expanded rapidly in recent decades. This large‐scale land‐use change has had great ecological, economic, and social impacts on both the areas converted to oil palm and their surroundings. However, research on the impacts of oil palm cultivation is scattered and patchy, and no clear overview exists. We address this gap through a systematic and comprehensive literature review of all ecosystem functions in oil palm plantations, including several (genetic, medicinal and ornamental resources, information functions) not included in previous systematic reviews. We compare ecosystem functions in oil palm plantations to those in forests, as the conversion of forest to oil palm is prevalent in the tropics. We find that oil palm plantations generally have reduced ecosystem functioning compared to forests: 11 out of 14 ecosystem functions show a net decrease in level of function. Some functions show decreases with potentially irreversible global impacts (e.g. reductions in gas and climate regulation, habitat and nursery functions, genetic resources, medicinal resources, and information functions). The most serious impacts occur when forest is cleared to establish new plantations, and immediately afterwards, especially on peat soils. To variable degrees, specific plantation management measures can prevent or reduce losses of some ecosystem functions (e.g. avoid illegal land clearing via fire, avoid draining of peat, use of integrated pest management, use of cover crops, mulch, and compost) and we highlight synergistic mitigation measures that can improve multiple ecosystem functions simultaneously. The only ecosystem function which increases in oil palm plantations is, unsurprisingly, the production of marketable goods. Our review highlights numerous research gaps. In particular, there are significant gaps with respect to socio‐cultural information functions. Further, there is a need for more empirical data on the importance of spatial and temporal scales, such as differences among plantations in different environments, of different sizes, and of different ages, as our review has identified examples where ecosystem functions vary spatially and temporally. Finally, more research is needed on developing management practices that can offset the losses of ecosystem functions. Our findings should stimulate research to address the identified gaps, and provide a foundation for more systematic research and discussion on ways to minimize the negative impacts and maximize the positive impacts of oil palm cultivation.     

Research on basal stem rot (BSR) of ornamental palms caused by basidiospores from <Emphasis Type="Italic">Ganoderma boninense</Emphasis>

Basidiospores were isolated from the fruiting bodies of Ganoderma infecting oil palms from an estate in Johor and from ornamental palms (including oil palms) from Singapore. The spores were then germinated to obtain homokaryotic mycelia. Based on clamp connection formation in paired hyphal fusions, tester strains were identified from the homokaryons isolated. Compatibility tests were then carried out using these testers to determine the relatedness of the homokaryotic Ganoderma isolates, both from Johor and from Singapore. Results from the compatibility tests showed that Ganoderma from both locations belong to the same species, while the Ganoderma isolates from Singapore share some common alleles. The pathogenicity tests carried out on Chrysalidocarpus lutescens seedlings using inoculum growing on rubber wood blocks showed that dikaryotic mycelia can cause basal stem rot infection.     

Total and heterotrophic soil respiration in a swamp forest and oil palm plantations on peat in Central Kalimantan,Indonesia

Heterotrophic respiration is a major component of the soil C balance however we critically lack understanding of its variation upon conversion of peat swamp forests in tropical areas. Our research focused on a primary peat swamp forest and two oil palm plantations aged 1 (OP2012) and 6 years (OP2007). Total and heterotrophic soil respiration were monitored over 13 months in paired control and trenched plots. Spatial variability was taken into account by differentiating hummocks from hollows in the forest; close to palm from far from palm positions in the plantations. Annual total soil respiration was the highest in the oldest plantation (13.8 ± 0.3 Mg C ha^?1 year^?1) followed by the forest and youngest plantation (12.9 ± 0.3 and 11.7 ± 0.4 Mg C ha^?1 year^?1, respectively). In contrast, the contribution of heterotrophic to total respiration and annual heterotrophic respiration were lower in the forest (55.1 ± 2.8%; 7.1 ± 0.4 Mg C ha^?1 year^?1) than in the plantations (82.5 ± 5.8 and 61.0 ± 2.3%; 9.6 ± 0.8 and 8.4 ± 0.3 Mg C ha^?1 year^?1 in the OP2012 and OP2007, respectively). The use of total soil respiration rates measured far from palms as an indicator of heterotrophic respiration, as proposed in the literature, overestimates peat and litter mineralization by around 21%. Preliminary budget estimates suggest that over the monitoring period, the peat was a net C source in all land uses; C loss in the plantations was more than twice the loss observed in the forest.     

Mycoparasitic Scytalidium parasiticum as a potential biocontrol agent against Ganoderma boninense basal stem rot in oil palm*

The objective of this study was to assess the interactions between Scytalidium parasiticum (Sp) and Ganoderma boninense, the causal agent of basal stem rot (BSR) in oil palm (Elaeis guineensis). When compared with Scytalidium ganodermophthorum and Scytalidium sphaerosporum, Sp showed greater inhibition towards all Ganoderma isolates during dual-culture assays. At the interaction zone, coiling of host hyphae, formation of short lateral enlarged contact structures, and production of appressorium-like organs organs were observed in Sp on G. boninense. These were followed by the degradation, shrinkage, and deformation of G. boninense mycelia. Sp reduced mycelial survival and fruiting body regeneration of G. boninense. Sp's non-volatile metabolites suppressed the growth of G. boninense. Our results show that Sp could be a necrotrophic mycoparasite of G. boninense. Nursery experiments revealed that Sp was non-pathogenic to oil palm seedlings, and it could suppress Ganoderma infection and reduce disease severity. Sp increased the height of palms in the positive control with non-Ganoderma-inoculated rubber wood block and Sp inoculum compared to similar control without Sp. Leaf area was greater in the G. boninense G8 inoculated palms when Sp was present compared to without Sp. These results show that Sp might be a potential biocontrol candidate against BSR.     

Reconciling Oil Palm Expansion and Climate Change Mitigation in Kalimantan,Indonesia

Our society faces the pressing challenge of increasing agricultural production while minimizing negative consequences on ecosystems and the global climate. Indonesia, which has pledged to reduce greenhouse gas (GHG) emissions from deforestation while doubling production of several major agricultural commodities, exemplifies this challenge. Here we focus on palm oil, the world’s most abundant vegetable oil and a commodity that has contributed significantly to Indonesia’s economy. Most oil palm expansion in the country has occurred at the expense of forests, resulting in significant GHG emissions. We examine the extent to which land management policies can resolve the apparently conflicting goals of oil palm expansion and GHG mitigation in Kalimantan, a major oil palm growing region of Indonesia. Using a logistic regression model to predict the locations of new oil palm between 2010 and 2020 we evaluate the impacts of six alternative policy scenarios on future emissions. We estimate net emissions of 128.4–211.4 MtCO₂ yr^-1 under business as usual expansion of oil palm plantations. The impact of diverting new plantations to low carbon stock land depends on the design of the policy. We estimate that emissions can be reduced by 9-10% by extending the current moratorium on new concessions in primary forests and peat lands, 35% by limiting expansion on all peat and forestlands, 46% by limiting expansion to areas with moderate carbon stocks, and 55–60% by limiting expansion to areas with low carbon stocks. Our results suggest that these policies would reduce oil palm profits only moderately but would vary greatly in terms of cost-effectiveness of emissions reductions. We conclude that a carefully designed and implemented oil palm expansion plan can contribute significantly towards Indonesia’s national emissions mitigation goal, while allowing oil palm area to double.     

Early immunodiagnosis of Ganoderma infecting coconut seedlings and palms by using monospecific polyclonal antibodies

Among the various fungal diseases affecting plantation crops viz., coconut, aracanut, oil palm, etc. in India, basal stem rot (BSR) caused by species of Ganoderma is the most destructive. A limiting factor in controlling the BSR disease is the lack of reliable diagnostic method(s) for early diagnosis. In this study we generated two different types of antiserum for diagnosis of Ganoderma using the purified monospecific protein (62 kDa) (MS) and crude sporophore extract (SE). We also tested the cross-reactivity with the soil-borne and saprophytic fungus collected from different parts of coconut palm. The antiserum developed against the MS and SE showed 1:700 and 1:3000 titre values for the detection of Ganoderma. The MS antisera developed showed very low or almost no cross-reaction when compared to SE antisera of Ganoderma. In the DIBA test, at a 1:10 dilution of antigen, 1:1000 dilution of CMP and ECP antisera, 1:5000 dilution of secondary antibody gave clear distinctions in colour development between healthy and diseased samples. In DIBA test, both types of antisera were used separately for pathogenicity tests. MS antisera showed a positive reaction for purified protein, artificially infected roots and infected field palm. A mild reaction was observed against infected field trunk but a negative reaction was observed for lesions and leaf samples. In the case of SE antisera, a negative reaction was observed for all leaf samples, healthy roots and healthy trunk samples but positive reactions were observed for positive control, artificially inoculated roots, infected field roots, infected trunk and lesions samples. Therefore, both ELISA and DIBA tests may be useful in the detection of infection at the earliest stage of disease development and this will certainly help in the development of management strategies against Ganoderma disease in palm crops in advance.     

Effects of peat swamp logging and agricultural expansion on species richness of native mammals in Peninsular Malaysia

The biodiversity inhabiting tropical peat swamp forests in Southeast Asia is currently threatened by commercial logging and agricultural expansion. The occurrence of mammals in such forests is often poorly known and the factors influencing their occurrence in these ecosystems have rarely been quantified. We aim to determine the key habitat and landscape drivers of mammal species richness in fragmented peat swamp reserves. We conducted camera trap surveys in the North Selangor Peat Swamp Forest (NSPSF), the last remaining area of peat swamp forest on the west coast of Peninsular Malaysia. We also measured vegetation structure and landscape metrics to investigate the relationship between these factors and mammal richness. We recorded a total of 16 mammal species from 45 sampling sites using camera traps located in peat swamp forest reserves. Mammal species richness increased with the abundance of large trees and distance away from roads. Species richness decreased significantly with canopy cover and height, the abundance of fallen trees, the abundance of forest palms and saplings, distance away from rivers, and a measure of landscape compositional heterogeneity. Our findings underscore the high conservation value of logged peat swamp forests and the urgent need to halt further deforestation. We recommend: (1) protecting riparian habitat; (2) avoiding further forest conversion particularly areas supporting large trees into oil palm plantations; and (3) limiting road development within and around the NSPSF.     

Pathogenicity of Fusarium oxysporum Isolates from Malaysia and F. oxysporuin f. sp. elaeidis from Africa to Seedlings of Oil Palms (Elaeis guineensis)

Pathogenicity tests with Fusarium oxysporum isolated form Malaysian oil palm were made with oil palms seedlings raised form Malaysian seed as well s with wilt-susceptible seedlings gown from African seed. Oil palm seedlings grown form Malaysian seed were also inoculated with African isolates of F. oxysporum f. sp. elaeidis and F. oxysporum var. redolens. The experiments were made under normal soil moisture conditions and under water stress. F. oxysporum f. sp. elaeidis isolates form Africa were pathogenic to oil palm seedlings from Malaysian seeds but the Malaysian F oxysporum isolates were non-pathogenic to plams grown from Malaysian seed or the wilt-susceptible palms from African seed. Seedlings from Malaysian seed proved to be highly susceptible to the vascular wilt disease caused by F. oxysporum f. sp. elaeidis as 75–90% of the palms were infected. The susceptibility of the palms from Malaysian seed varied with different African isolates tested. The Yaligimba isolate from Zaire which was found to be F. oxysporum var. redolens was the most virulent. Disease was more severe when oil palm seedlings were subjected to a period of water stress. The incidence of death in the seedlings under stress conditions was 45% as compared with only 15% for palms grown under normal conditions.     

High heterotrophic CO<Subscript>2</Subscript> emissions from a Malaysian oil palm plantations during dry-season

Tropical peatlands are currently being rapidly cleared and drained for the establishment of oil palm plantations, which threatens their globally significant carbon sequestration capacity. Large-scale land conversion of tropical peatlands is important in the context of greenhouse gas emission factors and sustainable land management. At present, quantification of carbon dioxide losses from tropical peatlands is limited by our understanding of the relative contribution of heterotrophic and autotrophic respiration to net peat surface CO₂ emissions. In this study we separated heterotrophic and autotrophic components of peat CO₂ losses from two oil palm plantations (one established in ‘2000’ and the other in 1978, then replanted in ‘2006’) using chamber-based emissions sampling along a transect from the rooting to non-rooting zones on a peatland in Selangor, Peninsular Malaysia over the course of 3 months (June–August, 2014). Collar CO₂ measurements were compared with soil temperature and moisture at site and also accompanied by depth profiles assessing peat C and bulk density. The soil respiration decreased exponentially with distance from the palm trunks with the sharpest decline found for the plantation with the younger palms with overall fluxes of 1341 and 988 mg CO₂ m^?2 h^?1, respectively, at the 2000 and 2006 plantations, respectively. The mean heterotrophic flux was 909 ± SE 136 and 716 ± SE 201 mg m^?2 h^?1 at the 2000 and 2006 plantations, respectively. Autotrophic emissions adjacent to the palm trunks were 845 ± SE 135 and 1558 ± SE 341 mg m^?2 h^?1 at the 2000 and 2006 plantations, respectively. Heterotrophic CO₂ flux was positively related to peat soil moisture, but not temperature. Total peat C stocks were 60 kg m^?2 (down to 1 m depth) and did not vary among plantations of different ages but SOC concentrations declined significantly with depth at both plantations but the decline was sharper in the second generation 2006 plantation. The CO₂ flux values reported in this study suggest a potential for very high carbon (C) loss from drained tropical peats during the dry season. This is particularly concerning given that more intense dry periods related to climate change are predicted for SE Asia. Taken together, this study highlights the need for careful management of tropical peatlands, and the vulnerability of their carbon storage capability under conditions of drainage.     

The influence of agricultural system,stand structural complexity and landscape context on foraging birds in oil palm landscapes

Functional diversity, an important element of avian biodiversity, can be examined by quantifying foraging guild composition. Understanding the ecological processes that underpin functional diversity of birds in oil palm Elaeis guineensis landscapes is important because different foraging guilds are likely to be influenced in different ways by land use practices. We surveyed birds at 55 sites within oil palm landscapes and at 20 sites within logged peat swamp forest, recording 208 species belonging to 19 foraging guilds. Oil palm landscapes supported a lower abundance of insectivorous, granivorous and omnivorous birds than did logged peat swamp forest despite the latter being severely degraded due to intensive timber extraction. However, abundances of other groups of foraging birds, such as raptors and wetland taxa, were higher in oil palm landscapes than logged peat swamp forest. Frugivorous species were more abundant in smallholdings than plantation estates, probably because of the presence of native trees. Foraging guild diversity was explained by stand‐level attributes such as stand age, vegetation cover, epiphyte persistence and canopy cover. However, each foraging guild exhibited unique responses to different oil palm management regimes and stand‐level attributes. Only arboreal omnivores and terrestrial frugivores were affected by the proximity of nearby natural forest. This diversity of responses implies that the occurrence of particular avian foraging guilds may not be a suitable ecological indicator of best‐practice palm oil production. Our study also suggests that multiple conservation measures will be needed in oil palm landscapes irrespective of management regimes, including: (1) the maintenance of ground layer vegetation cover; (2) the pruning of oil palm canopy to permit light penetration to the ground layer; (3) re‐vegetation of parts of oil palm landscapes with native trees; and (4) retention of natural and/or secondary forest patches within the boundaries of plantations.     

Fractionation and bioaccumulation of copper and zinc in wetland soils of the Niger Delta determined by the oil palm

Abstract

The concentration, mobility, bioavailability, distribution and associations of two essential micronutrient elements (copper and zinc) to the oil palm in wetland soils of the Niger delta region of Nigeria was assessed by means of chemical fractionation analysis. The water soluble and plant available fractions were introduced into the sequential extraction scheme. Also assessed were the bioaccumulation (concentration and distribution) of these metals in the leaves and fruits of the oil palm of various ages found around the soil profiles. Copper was obtained more in the amorphous Fe-oxide fraction (151.05 mg kg^?1), but evenly distributed in the exchangeable component (16.16%) with a maximum value of 126.6 mg kg^?1. The water soluble and plant available fractions had 16.15 and 7.54% distribution of Cu respectively. Zinc had 2.35 and 30.42% distribution in the water soluble and plant available fractions respectively. The lowest mean amount of Cu (1.33 mg kg^?1) was determined in the leaves of palms of ages 15–32 years. Palms greater than 60 years had the highest mean concentration of copper (3.91 mg kg^?1) in the leaves while the endosperm (kernel) of palms between 2 and 10 years had concentration of 9.07 mg kg^?1. The fibrous oily mesocarp had the highest amount (16.78 mg kg^?1) of copper in the older palms (>60 years). Similarly, Zn was dominant in the older palms with a mean concentration of 187.14mg kg^?1 obtained in the endosperm (kernel). The bioaccumulation pattern of both metals by the palms irrespective of age and the fractionation analysis revealed sufficient bioavailable and reserved amounts of Zn and Cu in the wetland soils.     

Pupation site and emergence time influence the mating success of bagworm females,Oiketicus kirbyi

In commercial oil palm plantations in Costa Rica, we tested the hypotheses that pupation site and emergence time affect the mating success of protogynous female bagworms,Oiketicus kirbyi (Guilding) (Lepidoptera: Psychidae). Greater proportions of female than male pupae on upper leaves of oil palms and greater proportions of mated females in the upper rather than lower crown strata support the hypothesis that selection of pupation site by female larvae influences the mating success of adults. Increasing captures of males with increasing trap height further suggest that enhanced mating success of females in tree tops may be attributed either to most effective dissemination of sex pheromone on higher sites, or to males foraging predominantly in the upper strata of oil palms. As the majority of females pupated in the middle rather than upper crown of oil palms, selection of pupation site by females may be affected by additional as yet unknown factors. Emergence of females significntly preceded emergence of males. Increasing proportions of mated females throughout the emergence seasons probably resulted from an increased ‘availability’ of males. In tropical rainforests with local variations inO. kirbyi developmental time and stage, protogyny may represent an evolutionary strategy that furthers outbreeding.     

Ganoderma – a basal stem rot disease of coconut palm in south Asia and Asia pacific regions

Basal stem rot (BSR) caused by the species of Ganoderma is one of the most devastating diseases of numerous perennial, coniferous and palmaceous hosts. In forest systems, Ganoderma has an ecological role in the breakdown or delignification of woody plants. Symptoms of BSR disease can take several years to develop, and the presence of the pathogen (such as indicated by fruiting bodies) is often only visible when the fungus is well established and more than half of the bole tissue has been decayed, leaving no chance for the grower to cure the infected palms. Soils with poor drainage and water stagnation during rainy seasons were found to favour the disease. A limiting factor in controlling the BSR disease is the lack of reliable diagnostic method(s) for early diagnosis. Amendment of calcium nitrate in soil is one of the methods for the management of Ganoderma disease in palms. A combination of biological and systemic fungicides along with good cultural practices will effectively control the BSR disease in palms.