and b Malaysian Palm Oil Board (MPOB), No. 6, Persiaran Institusi, Bandar Baru Bangi, Kajang, 43000 Selangor, MalaysiaVascular wilt of oil palm caused by Fusarium oxysporum f. sp. elaeidis (Foe) is a devastating disease in West and Central Africa. As the oil palm industry in southeast Asia is still expanding, so is the oil palm germplasm collection through the importation of seed and pollen from Africa, the centre of diversity for Elaeis guineensis. There is a risk of inadvertent spread of the disease on contaminated seed or pollen. Regular re-evaluation of the reaction of currently grown palm genotypes towards Foe is clearly required for biosecurity. This study has demonstrated that four Malaysian oil palm progenies, three in current or recent commercial use, are highly susceptible to infection by at least one of two African isolates of Foe, representing different countries, aggressiveness and vegetative compatibility groups. Symptoms and reduction of palm growth generally reflected the extent and intensity of systemic colonization by Foe. Progeny PK 5463 expressed partial resistance to Foe isolate F3, but not to isolate 16F, displaying significantly milder symptoms and supporting less widespread vascular colonization. This relatively incompatible interaction was used to study expression of potential defence-related genes during root infection when compared to a susceptible palm-isolate combination. The only significant response was an early up-regulation of chitinase in resistant palms. The research revealed at least one progeny-isolate differential interaction, and the associated resistance expression suggests a component of tolerance, because colonization by Foe was systemic in both compatible and incompatible combinations.

Vascular wilt disease caused by Fusarium oxysporum f. sp. elaeidis (Foe) has devasted oil palm in west and central Africa. This study investigates the spatial distribution of Foe, whereby non-random, clustered patterns of the disease were recorded in four separate plantations in Ghana; infection from tree to tree via elongating roots therefore plays a more significant role than aerial distribution by conidiospores, with management implications. Control of Foe with disease-resistant palm lines can depend on the genetic variability of Foe isolates. Twenty-two putative Foe isolates from several African countries, including Ghana, were obtained from oil palms in infected areas for phylogenetic analysis along with 19 fungal outgroups, using the TEF-1α gene. The data showed Foe isolates have a monophyletic origin, and therefore limited diversity. Palm adapted isolates of F. oxysporum appear to have evolved independently, as ff. spp. elaeidis, albedinis and canariensis were nested into three independent groups. Slowly developing (chronic) and fast, severe (acute) Fusarium wilt are both evident in plantations and we provide preliminary evidence that Foe isolates' different aggressiveness might contribute to this variation. Sampling for Foe infection from xylem in extracted stem cores revealed the deficiency of field surveys based only on visual symptoms.

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Goosegrass (Eleusine indica) is one of the weeds that has a problem of herbicide resistance to glyphosate.This study investigated the potential use of Phoma herbarum as a biological control agent of glyphosate resistant E. indica. Nursery and field experiments showed that the application of 10 6 conidial suspension of P. herbarum demonstrated biofungicidal activity whereby 91.70% of treated E. indica died whilst for field experiment the mortality rate was recorded at 80.00%. The effect of P. herbarum was noticeable at 14 days after treatment and continued to increase at 21 days and 28 days after application. This study also investigated the direct effects of a few common herbicides that were used to control E. indica in oil palm plantations. The study found that the P. herbarum was compatible with herbicide diuron and was able to cause 80.00% mortality to E. indica when diuron was applied at full strength. The percentage mortality of E. indica increased to 91.67% when half strength diuron was applied. Thus, this study was to report the effectiveness of P. herbarum as a potential biological control agent against resistant E. indica and compatible with herbicide diuron.