Eliminating of Pathogenic Soil borne Pythium Species Spreading Across the Marine Port of Duba

(Hashim Mohammed Al-Sheikh)

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Abstract

Pythium species are considered the most important soil born fungi. They are facultative heterotrophic microorganisms. Under proper conditions, it become highly virulent to plants (depending on the species), causing many diseases, especially in the first stages of growth. These fungi abound in heavy agricultural soil and Egypt is an important source for such fungi that can be transmitted to another country. This research aims to identify the method of transporting Pythium contaminated soil by from a famous agricultural country like Egypt to Saudi Arabia via the vehicle tires. A method to disinfect those cars and eliminate contaminants before they enter Saudi territory was introduced. Two hundreds and forty-six isolates belonging to seven species of Pythium were isolated and identified by morphological and molecular criteria. The species belong to Pythium aphanidermatum, Pythium deliense, Pythium diclinum, Pythium irregulare, Pythium oligandrum, Pythium spinosum and Pythium ultimum var. ultimum. These were isolated from the soil situated in folds of tires of 50 cars in Duba port that came from the Egyptian port of Hurghada, on September 7th, 2011. P. aphanidermatum, P. deliense and P. ultimum var. ultimum proved highly pathogenic to cucumber seeds germination causing 100% damping-off. P. irregulare, P. diclinum and P. spinosum var. spinosum were moderately pathogenic causing 74, 70 and 65% damping-off, respectively. On the other hand, P. oligandrum showed avirulent behavior towards cucumber germinating seeds with 0% damping-off. The anti-oospores efficacy of sodium hypochlorite (NaOCl) on transmission of Pythium spp. via cars tires was studied. Mean reduction of oospore viability due to treatment with NaOCl was proved. Total destruction of viability was achieved within 30 min exposure when oospores of all tested pythia were treated with 0.42% NaOCl. Elimination of oospores viability was achieved after 30 min exposure with treatment of 0.240% NaOCl in 6 out of the 7 species. This is the first report on transmission of Pythium species to Saudi Arabian via seaports. Key Words: Saudi Arabia, NaOCl, Egypt, Oospores, Port, Pythium spp.
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