ology of G. boninense in oil palm plantation, including in-contact roots with nearby Ganoderma boninense is a polyporoid fungus which grows on wood. PDF | The objective of this study was to screen the potential endophytic bacteria to be used as a biological control for Ganoderma boninense, the major causal. Request PDF on ResearchGate | Pathogenic Nature of Ganoderma boninense and Basal Stem Rot Disease | The oil palm industry is under threat of a prevailing .
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For the purposes of this data sheet only control of the disease in oil palms and coconuts is presented. See Ariffin et al. Cultural Control The identification of diseased palms is crucial to control Sanderson, and with the advent of rapid tests, diagnosis may be quicker in future allowing control measures to be implemented at an earlier stage.
Poor drainage, flooding, nutritional imbalances and heavy weed growth have all been reported to be associated with increased basal stem rot incidence in oil palms. However, as there is no evidence ganodrrma any direct effect, bnoinense in growth conditions, although beneficial to the palm, cannot be regarded as direct control effects against basal stem rot disease Turner, Mounding Mounding with earth around the stem base has previously been attempted, not only to provide additional support, but also to stimulate root production Turner, In a number of estates in Sumatra, mounding has become routine practice for all infected palms over 15 years old, prolonging their economic life Hasan and Turner, Ganoderka has been shown to be an economic technique in that the production of only one more oil palm bunch by the diseased palm will pay for the cost of the mounding in Indonesia.
However, in Malaysia where mounding was evaluated, the cost-effectiveness of such treatments should be considered since it may take 2 or more years to recover treatment costs Ho and Khairuddin, vanoderma However, fanoderma authors tested the benefits of soil mounding in conjunction with surgery and fumigation with dazomet in mitigating the effects of infection and these treatments would be more labour intensive and involve the purchase of chemicals. Ho and Khairuddin reported that soil mounding ganodema fumigation and soil mounding alone prolonged the productivity of palms, primarily through the physical benefit of preventing gannoderma weakened boles from being toppled by wind.
Isolation pits The isolation of symptomatic palms, by digging trenches to prevent possible mycelial spread of the pathogen to neighbouring healthy palms, has been discussed as a control measure since early this century Anon. However, this agronomic practice has generally proved to be ineffective either because the trench depths were insufficient to remove all infected root material Hasan and Turner, or because the trenches were boninensd maintained.
Also, this control measure could only be applied to visibly diseased palms, with untreated symptomless palms remaining a potential source of infection. This may be improved with the advent of diagnostic techniques.
However, economically, the price of palm oil is so low the labour costs to conduct this work especially where there is a high incidence of the disease, are prohibitive in many oil palm plantations.
In addition, this control strategy was based on the assumption that infection occurs by mycelial spread from root to root between neighbouring palms, which has been since been shown to occur only infrequently and over a very localised area Miller, ; Miller et al. If Ganoderma spreads by other mechanisms, such as basidiospore dispersal, the isolation of palm root systems would be ineffective regardless of trench depth. Sanderson discussed disease management in Papua New Guinea, which is based on prevention of the formation of basidiomata brackets.
Infected palms are removed from the plantations, the trunk base and root ring is excavated to a depth of cm below ground, and the areas covered with soil to prevent further bracket formation.
Curative Surgery The manual excision of infected tissues from lesions in the outer stem tissues of palms was a widely adopted treatment strategy in the s. However, regular inspection to ensure treatment of palms at an early stage of infection, and mixed results in treated palms, led to a decline in the practice. More recently, mechanisation of the procedure has led to a renewed interest in surgery Singh,although limitations still exist. This form of treatment is of little use for young palms, where lesions typically radiate outwards from the centre of the stem.
Additionally, if basidiomata do emerge in young palms, it is likely that the decay will be too advanced for effective surgery.
Palms over 25 years old are very tall, and as a result may collapse after the excision of even small lesions Turner, Furthermore, surgery frequently requires repetition, as infection often resurges if lesions are not completely removed. Chemical Control The effective use of chemical control for treatment of Ganoderma-infected palms is limited because both visibly infected and sub-clinical palms may harbour a firmly established infection by the time treatment is applied.
Additional difficulties may occur in the effective placement of fungicides, as lesions are frequently very large. Furthermore, concentrations of residues of any fungicide in palm oil may prevent adoption within the industry.
Preliminary results on trunk injection of fungicides into infected oil palms indicated that triadimenol a systemic conazole fungicide may increase their economic lifespan, with treated palms remaining alive 52 months after the original basal stem rot diagnosis Chung, Evaluation of pressure injection of fungicides by Ariffin has indicated that tridemorph appears to limit the spread of infection.
Ariffin and Idris reported good results using bromconazole using a pressure injection apparatus. Studies on the use of dazomet, which releases the soil fumigant methyl isothiocyanate on contact with water, indicated encouraging results both in vitro and in the field Ariffin and Idris, b.
Ariffin and Idris c reported fungitoxic effects of methyl isothiocyanate to Ganoderma spp.
basal stem rot of oil palm (Ganoderma boninense)
In coconut, Rao et al. Chemical control can at best delay the disease. The tree is not cured and injection using chemicals is usually too expensive for most growers. However, with the advent of rapid diagnostic tests See Diagnostic Methods there is a possibility of using chemical control earlier and thus possibly more chance of success.
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Nevertheless for small holders and plantations alike, chemical control remains an expensive option. Biological Control Several promising antagonists, mainly species of Trichoderma, Aspergillus and Penicillium have been boninehse as antagonistic to G.
Singh evaluated the incorporation of Trichoderma sp. One possible explanation for this may be the low natural incidence of Trichoderma species in the soil. Even augmenting with Trichoderma did not seem to control the disease. At the end of their experiments, Sariah and Zakaria reported that disease incidence in treatments using T. These authors also reported the effect of a number of other soil amendments.
Soil application of calcium nitrate suppressed the development of basal stem rot. Calcium nitrate did not reduce mycelial growth of the pathogen, suggesting that the effect of calcium in reducing infection was indirect Sariah et al.
Bhaskaran also reported the effects of several amendments including Trichoderma in various organic manures on basal stem rot in coconut Bhaskaran, The biofungicide is applied as either preventive or curative treatments Soepena et al.
Other Trichoderma and Gliocladium species are also active against that pathogen but are better at degrading organic matter in the field. However, doubts do exist over the survival of such an organism in clay soils, or at sufficient depths in other soil types, because of its poor survival under anaerobic conditions.
Undoubtedly, the times of greatest practical significance for the control of basal stem rot in oil palm is during replanting second or third generation oil palm on oil palm or at the time of preparation of a site, especially when one is planting oil palms after coconuts. Land preparation Land preparation procedures are based on the assumption that infection occurs by mycelial spread from root to root and that the removal of stumps and large pieces of debris will eliminate viable residual inoculum from the field before planting of the next crop.
Such practices have been widely adopted throughout South-East Asia, to different degrees, dependent on basal stem rot incidence in previous plantings, labour availability and the costs involved.
Clean clearing Current procedures involve excision and removal of all remaining bole fragments by digging pits 1. However, the depth required to remove all bole fragments and the majority of the boniennse mass varies with the soil type and the level of the water table Singh, Cauterization by burning of the root-ends along the sides of the pits is also common.
In areas with a high incidence of basal stem rot, it is generally thought that all remaining fragments from the previous crop should be brought to the surface for subsequent removal. However, as this is frequently regarded as too costly, and since open burning is now forbidden in Malaysia bononense the Clean Air Regulations Act ofa common practice is to shred all palm fragments.
These can either be scattered over the whole field or bonimense stacked in rows and covered with a legume cover crop to facilitate decay and to deter colonization of the palm debris from Oryctes. Shredding oil palm tissues has been adopted in some areas in Malaysia but not in Sumatra Flood et al.
Although clean-clearing practices generally result in lower disease incidence in replanted oil palms in comparison with other replanting techniquesthe incidence of the disease may still be unacceptably high. Doubts bonunense been raised regarding the efficacy of this approach, with evidence from a number of oil palm estates suggesting that infection can still become established progressively earlier with each planting cycle, even after clean clearing.
Furthermore, although legume cover crops may accelerate decay of oil palm debris, reports have also suggested that gaonderma may encourage Ganoderma Dharmaputra et al. Hasan and Turnerreported that subsequent infection incidence decreases ganpderma increased clearing depth, implying that clean clearing may frequently not be sufficiently thorough in practice.
Also the fact that roots form a small but significant source of inoculum Hasan and Turner, would suggest that clean clearing will never be able to remove all potential sources of infection.
Windrowing This technique is less labour intensive than clean-clearing: Although data are limited, this technique has been shown to be almost as effective in limiting losses in the subsequent crop as clean-clearing. A comparative study of replanting techniques in oil palms Hashim, indicated that clean-clearing was the most effective in reducing subsequent disease incidence from Nonetheless, windrowed material does represent significant problems with regard to potential sources of inoculum Hasan and Turner, ; Flood et al.
The roots of young seedlings will come into contact with windrowed material probably years after planting. Poisoning of the old palms prior to felling, and cutting the material into sections, is thought to speed natural decay. Windrowed material is also a source of Oryctes and the rapid degradation of this material by antagonistic fungi has been proposed Flood et al. However, caution is advised as some fungi that degrade the oil palm tissue more rapidly that G.
Host-Plant Resistance In the long term, breeding for resistance to this disease does offer a practical, stable means of control to this disease. A trial conducted in Sumatra with West African dura varieties of oil palm revealed a slower rate of basal stem rot disease development by comparison with local Sumatran tenera material, indicating that differential resistance to Ganoderma does occur in different planting materials.
However, as yet, there are no commercially available oil palm varieties with resistance to G. Many plantation companies in South-East Asia are developing breeding programmes but one of the major limiting factors has been the difficulty of producing a rapid, reliable pathogenicity test with which to screen oil palm progenies at the seedling stage and thus screen out the very susceptible progenies before field testing.
To screen hundreds of progenies, a more rapid test is needed. In the absence of rapid seedling tests, field trials of many progenies are being conducted in Malaysia and in Sumatra where young palms are planted in areas of high disease incidence.
Go to distribution map The earliest external symptoms of basal stem rot of oil palms occur gqnoderma the bominense, generally after at least half of the cross-sectional area of the boinnense base has been destroyed. Decay leads to a restriction of water and nutrient supply to the aerial parts, causing symptoms resembling those of water stress and malnutrition Turner and Gillbanks, Visual symptoms alone are thus not necessarily diagnostic of basal stem rot, as other factors leading to water stress, such as drought, high soil water salinity or hyperacid soils also cause similar foliar symptoms Turner, In young palms, ganodrema symptoms of basal stem rot comprise a yellowing or mottling of the lower fronds, followed by necrosis.
Young unfolded leaves become chlorotic and may be reduced in length, sometimes with necrotic tips. As the disease progresses, palms may take on a pale appearance, with retarded growth and spear leaves remaining unopened. Similar symptoms are observed in mature palms, with multiple unopened spear leaves and a generally pale leaf canopy.
Ultimately, affected palms may die, the necrosis beginning with the oldest fronds and extending to younger regions of the crown. Palms normally die within yanoderma to 12 months after the appearance of unexpanded spear leaves. Infection produces a dry rotting of internal tissues at the stem base or root bole and so at any stage in the disease process, the stem or root bole of the infected palm may fracture and the palm will collapse.