Distribution and Pathogenic Potential of Soil Fusaria from Selected Oil Palm Habitats in West Malaysia

A total of eight species and two varieties of Fusarium was isolated from the sampling sites in the oil palm habitat. Fusarium solani and Fusarium oxysporum were the most prevalent species followed by Fusarium semitectum. The other species and varieties isolated showed a more sporadic occurrence. Generally, soils from oil palm rhizospheres and young palm areas contained a larger number and greater variety of Fusarium species than soils from the avenues and older palm areas. Pathogenicity tests of Fusarium species isolated showed that none were capable of producing vascular wilt or other diseases on oil palm seedlings. Some of the isolates, however, caused a reduction of growth in the test seedlings. Comparative studies of F. oxysporum isolates from oil palm habitat in Malaysia with F. oxysporum f. sp. elaeidis isolates from Africa showed that the two groups of isolates were ind istinguishable in their cultural, morphological and isozyme characteristics. Subsequent pathogenicity tests proved that the F. oxysporum isolates from Africa were pathogenic, causing vascular wilt on the Malaysian oil palm seed lings whilst the F. oxysporum isolates from Malaysia were non-pathogenic to the wilt-susceptible African oil palm seed lings and Malaysian oil palm seed lings. Inoculation of Malaysian F. oxysporurn isolates on Malaysian oil palm seedlings and wilt-susceptible African oil palm seedlings, subjected to an initial period of water stress, also did not result in showing any d isease symptoms

Cultural variants of fusaria from oil palm habitats

Variation in cultural and morphological characteristics existed in both the parent isolates and subcultures of 8 species of Fusarium isolated from oil palm soils. Based on pigmentation, mycelial characters and conidial measurements, different "morphological types" from parent isolates within a species were distinguished. Constant subculturing of the parent isolates gave rise to various cultural variants. The variants were the slimy-pionnotal, mycelial and ropy types or were in the form ofpatches or sections which differed in pigmentation from the parent colony

Isolation, growth and sporophore development of Ganoderma boninense from oil palm in Malaysia

A bundant mycelium of G. boninense could be isolated from sporophore tissues cultured on potato dextrose agar (PDA) and from single basidiospore germinating on PDA. The optimum temperature for mycelial growth was between 27-29°C and the best medium was lima bean agar. Sporophore development from mycelial culture was not successful on the various media employed. Studies on the growth of sporophore on infected trunks showed that growth was slow in the first 1-9 weeks, then increased rapidly till the fourteenth week after which growth rate decreased again

Germination studies of Ganoderma boninense spores from oil palms in Malaysia

Spores of Ganoderma boninense obtained from sporulating sporophores attached to infected oil palms or infected cut stumps, germinated readily but spores which were squeezed out from detached sporophores did not. None of the spores germinated during the first 24 hrs of incubation but by 30 hrs, 31.5- 64% of the spores germinated on various media. The most suitable medium for germination was lima bean agar followed by corn meal agar and rice dextrose agar. Spore germination was poor on Czapeks agar. Warmer temperatures of 25-- 31°C were more/favorable to germination than cooler temperatures of21 - 23°C

Ganoderma boninense Pat. from basal stem rot of oil palm (Elaeis guineensis) in Peninsular Malaysia

Several hundred sporophores of Ganoderma were collected from 5 - 40 years old palm trees infected with basal stem rot in 5 oil palm estates in Peninsular Malaysia. Based on the morphometric studies of the pores, dessepiments and basidiospores dimensions and other morphological characteristics, the sporophores were identified as belonging to a single species, G. boninense Pat

The role of rumen fungi in fiber digestion

Since the anaerobic rumen fungi were discovered in the rumen of a sheep over two decades ago, they have been reported in a wide range of herbivores fed on high fibre diets. The extensive colonisation and degradation of fibrous plant tissues by the fungi suggest that they have a role in fibre digestion. All rumen fungi studied so far are fibrolytic. They produce a range of hydrolytic enzymes, which include the cellulases, hemicellulases, pectinases and phenolic acid esterases, to enable them to invade and degrade the lignocellulosic plant tissues. Although rumen fungi may not seem to be essential to general rumen function since they may be absent in animals fed on low fibre diets, they, nevertheless, could contribute to the digestion of high-fibre poor-quality forages

Soil fusaria from oil palm habitats in Malaysia

Fusarium species were isolated from 22 sampling sites in 4 oil palm plantations located in different regions of Peninsular Malaysia using Peptone-PCNB medium. Eight species and two varieties of Fusarium viz., F. solani, F. oxysporum, F. oxysporum var. redolens, F. semitectum, F. moniliforme, F. moniliforme var. subglutinans, F. equiseti, F. longipes, F. lateritium and F. heterosporum were isolated. Among these, F. solani and F. oxysporum were the most prevalent species followed by F. semitectum and F. moniliforme. The other 5 species and 2 varieties of Fusarium were of sporadic occurrence. Generally, soils from areas with young palms had larger number and greater variety of Fusarium species when compared to soils from mature and old palm areas. The rhizosp here soil contained a greater variety of Fusarium species than soils in the avenue of palms (non-rhizosphre soil)

Effect of temperature and pH on growth pattern of Ganoderma boninense from oil palm in Peninsular Malaysia

Mycelial growth of boninense from floating inoculum disks incubates in flasks swirled daily was significantly more abundant than that from submerged inoculum disks in static flasks. The optimum temperatures for mycelial grow in both solid and liquid media were between 27-30°C. The mycelial growth pattern in liquid medium showed an initial lag phase of little growth (1-3 days), then a phase of rapid growth (6-18 days) and finally a phase of autolysis and decline in dry weight. The pH of medium change correspondingly with the change in growth pattern. As mycelial growth increased, the pH of medium decreased and when mycelial growth decreased during prolonged incubation, pH of medium increased. Optimum pH for mycelial growth was between 3.7-5.0

A study on fire hazards of oil tanks in urban areas with scale model experiments

Large fuel tanks are located in an urban area of Tsing Yi in Hong Kong, giving potentially high risks to people living nearby if a fire was to occur. Scale modeling experiments were carried out to investigate the potential of fire hazards. Propanol pool fires with five different scales of oil tanks were studied first. Appropriate tank sizes were then put in a 1/2500 architectural scale model on the Tsing Yi Island to study a fuel tank fire. Results show that the heat and smoke from a fire would affect occupants staying in areas near to the fuel tanks. Fire safety provisions in the storage areas must be demonstrated to function satisfactorily in big fire scenarios and upgraded when necessary. Emergency evacuation plans should be worked out to reduce the potential risk of having big disasters