PARASITIC AND PATHOGENIC EFFECTS OF Fuarium oxysporum f. sp. albedinis ISOLATES ON OKRA AND COLLARD PLANTS

Parasitic and pathogenic effects of four isolates of Fusarium oxysporum f. sp. albedinis, originating from the date palm, were tested on okra (Abelmoschus esculentus) and collard (Brassica oleracea var. viridis) plants, two plant species largely associated with date palm in a Moroccan oasis. Inoculation of the plants was carried out by soaking their roots in a spore suspension (106 spores/ml) of the Fusarium oxysporum f. sp. albedinis isolates. The presence of the fungus in the inoculated plants stimulated the growth of the plants. The length of the okra plants inoculated with isolates 1, 2 and 4, varies between 33.33 and 52.1 cm compared to the control plants (28.5 cm). The number of leaves emitted from inoculated plants varies from 15.22 to 18.74 while the number of leaves emitted from control plants is 12.33. The fresh weight of the aerial part varies between 30.86 and 34.73 g and the root part varies between 30.86 and 34.73 g and between 48.1 and 50.8 g, respectively, those of the control plants are 41.2 and 49.1 g. Although isolate 3, induced stunting on okra plants, the length of the inoculated plants was 26 cm compared to the control plants with 28.5 cm. This reduction also affected the fresh weight of the aerial and the root part with26.36 g and 49.08 g, respectively; those of the controls are 30.96 and 48.1 g. All Fusarium oxysporum f. sp. albedinis isolates tested have induced foliar symptoms in inoculated okra plants, with evidence of foliar alterations ranging from 0.38 (isolate 3) to 0.75 (isolate 1). Concerning inoculated plants of collard, isolates of Fusarium oxysporum f. sp. albedinis were also able to penetrate and colonize the upper levels of the plants, but the growth of these inoculated plants was not impeded, ranged from 11.16 to 11.96 cm with no difference as compared to the control plants (12 cm). The plants of collard inoculated with the studied isolates showed heterogeneous growth, some inoculated plants developed more than others and the average root mass of these plants (varies between 14.07 and 14.8 g) exceeds that of control plants (10.6 g). The parasitic specificity of Fusarium oxysporum f. sp. albedinis was also studied in this research.