Diseases of the Date Palm: Present Status and Future Prospects

Abstract

While date palm is affected by many diseases, bayoud remains the most serious one. It is caused by a soil born pathogen, Fusarium oxyspurum f .sp. albedinis. It has affected practically all Moroccan palm groves as well as those of western and central Algerian sahara, where it has respectively killed more than 12 million in Morocco and three million in Algeria and has accelerated the desertification phenomenon. External and internal symptoms as well as identification methods of F.o. f. sp. albedinis by pathogenicity test, cultural characteristics, and vegetative compatibility were reviewed and discussed. Small distance contamination occurs by root contact between diseased trees and healthy ones, and at large distances through the movement of contaminated planting material (offshoots, symptomless carriers) and infested soil and irrigation water. Prophylactic measures as well as chemical, cultural, biological and genetic controls were reviewed. It appears that the most productive mean lies in research into resistant cultivars. Hundreds of genotypes have been selected and introduced for micro-propagation and planted in infested areas to rehabilitate date palm oasis ravaged by bayoud. Among other date palm diseases Khamedj (Mauginiella scaettae), fruit rot (due to numerous fungi), Black scorch (Thielaviopsis paradoxa), Belaat (Phytophtora sp.) are of minor importance and of sporadic occurrence. However, they become serious and cause heavy losses under favorable conditions and when proper sanitation is not applied. Two serious and fatal diseases of unknown causes (AI Wijam and the Brittle leaf disease) as well as many other diseases and physiological disorders of minor importance were also reviewed.