Journal of Oil Palm Research Vol. 3 No. 2 1991 Dec, p. 329-335
A NON-DESTRUCTIVE QUANTITATIVE METHOD FOR THE ASSESSMENT OF INFECTION OF OIL PALMS BY FUSARIUM OXYSPORUM F. SP ELAEIDIS
A non-destructive technique, involving removal of cylinders from stems with an auger, is described for the quantification of disease in mature oil palms infected with Fusarium wilt. Reisolation from cores confirmed that discoloration of vascular tissue is diagnostic for Fusarium wilt.
Good agreement was obtained between disease assessment based upon leaf symptoms and this new technique. Auger sampling was the more sensitive method and in some crosses revealed 50% infection in otherwise symptomless palms. The absence of the pathogen in older ‘resistant’ palms indicated that they were truly resistant and not tolerant to the disease.
High levels of vascular occlusion occur in diseased palm trunks but not in roots, which suggests that blockage of the trunk xylem system is the critical phase in symptom development.
Auger sampling in Malaysia failed to reveal the presence of the fungus inside palm trunks.It is suggested that this technique could be useful in breeding programmes to identify resistant palms and reduce the risk of collecting seed from infected but symptomless palms. Other uses for the auger are also described.
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* Crop Protection Group,
School of Biological Sciences,
University of Bath, BATH BA2, 7AY, U.K.
+ Joint Research Scheme,
(Plantation Lever au Zaire and Societe au Culture au Zaire),