Fusarium wilt (Fusarium oxysporum f.sp elaeidis) is the most serious disease of oil palm in Africa. Control measures are dependent upon breeding for resistance, but the lack of a rapid screen for resistance and lack of understanding of the underlying resistance mechanisms has constrained breeding programmes. A novel petiole infusion technique is reported that exploits the ability of the majority of petiole cells to express disease resistance or susceptibility. A clear correlation was found between disease resistance or susceptibility of six clones and external symptoms and fungal colonization in petioles. Antifungal compounds accumulated in resistant but not in susceptible clones in response to inoculation; there was also some evidence of preformed antifungal compounds in resistant clones. Further investigation of resistance mechanisms can be undertaken using this model system. The use of this novel technique, both as a potential rapid replacement for current nursery selection methods (time reduced from 8 months to 8 days) and as an assessment of resistance in individual field palms, is discussed.*

ABSTRACT:In different parts of the world, attention is being paid to exploitation of higher plants as biodegradable fungicides in the control of most plant pathogenic fungi. Different spices of the Zingiberaceae family have been tested for their antifungal properties, but there exists little or no information on the antifungal potential of a particular member of that family; Aframomum sceptrum on fungal pathogens of some economic important palms in Nigeria. In this study, the phytochemical composition of the seed extracts of this spice was analyzed by standard methods while the antifungal activities of polar and non polar extracts of the spice was tested on two major isolates affecting the Oil palm, Fusarium oxysporum f.sp elaeidis and Hypocrea lixii (IMI 501885) Cold extraction using Acetone, Ethanol, Hexane, Methanol, and Diethylether solvents were used in the seed extract preparation. The broad spectrum fungicide, Mancozeb (80% wettable powder) was used as the positive control while the negative control was Dimethyl sulphoxide. The Dimethyl sulphoxide was also used to reconstitute the solvent extracts by dissolving the extracts and fungicides in appropriate amount of 15 % (v/v) to obtain a concentration of 0.0624g/ml. The phytochemical screening revealed the presence of the following phytochemicals in different quantities; Alkaloids, Terpenoids, Anthraquinones, Flavonoids Tanins, Saponins. Results obtained showed that all the extracts had a significantly higher antifungal effect (p< 0.05) than the broad spectrum fungicide, Mancozeb at 2000ppm. Non polar hexane seed extract had the highest percentage inhibition of 60.26% on Hypocrea lixii (IMI 501885 while the Polar ethanolic extracts with a percentage inhibition of 52.73 % on Fusarium f.sp elaeidis. Amongst all the extracts used in this study, the seed extracts that gave a low percentage inhibition of 42.45% was the non -polar acetone seed extract on Fusarium oxysporum fsp. elaeidis and methanol extract on H .lixii with the least percentage inhibition of 42.31%. The implications of these findings are discussed. © JASEM http://dx.doi.org/10.4314/jasem.v18 i2.4

Autoclaved oil palm kernels were inoculated with spores of seedborne isolates of either Aspergillus flavus, A. niger, Penicillium chrysogenum, P. janthinellum, Paecilomyces varioti, Syncephalastrum racernosum or Fusarium oxysporum. At O , 2 , 4 and 8 weeks after inoculation, determinations were made of the moisture content, oil, free fatty acids (FFA), sugars and protein nitrogen. The principal biochemical changes induced by these fungi were increases in moisture content and FFA, decreases in total oil and total sugars and a degradation of protein nitrogen. Aspergillus flavus caused the greatest changes, and P. varioti caused the least changes under the moisture conditions of this experiment. The main type of deterioration was hydrolytic rancidity of the oil, resulting in a dark reddish-orangecoloured oil and a discoloration of the kernel meal.