Investigation on the interaction between the root-knot nematode Meloidogyne javanica and Fusarium oxysporum f. sp. radicis-cucumerinum on some cucumber cultivars under greenhouse condition

In order to study the interaction of Fusarium oxysporum f. sp. radicis-cucumerinum and Meloidogyne javanica a survey on three cucumber cultivars was conducted in the greenhouse condition. The experiments were laid out in a factorial experiment based on completely randomized design (CRD) within 14 treatments including control, fungi alone, nematode alone in four inoculations level viz. 1500, 3000, 4500 and 6000 J2s, fungus + nematode simultaneously, fungus a week after nematode inoculation with 4 replications. Simultaneous fungus and nematode (6000 J2s) inoculation resulted in a %23.07 reduction in nematode gall index. The results showed that the highest mean egg number and number of egg sac per gram of root and gall index in the three cucumber cultivars were 3155.2, 15.30 and 4.33, respectively, for inoculation of the plant with 6000 nematode juvenile. The presence of nematodes (6000 J2s) increased the wilting index by 67.81% compared to fungus inoculation alone, and also, in fungal inoculation treatments, after the nematode inoculation (6000 J2s), the wilting index increased by 35.03% compared to the simultaneous inoculation. The results indicated that decreasing of 27.23% fresh shoot mass and the increasing of 3.5-fold wilting index of the cucumber cultivars to control caused by M. javanica at 6000 J2 → F. oxysporum f. sp. radicis-cucumerinum (one week later of inoculation) after 45 days. In conclusion, the results indicated that simultaneous infection of M. javanica and F. oxysporum f. sp. radicis-cucumerinum have synergistic effect on disease which was quite clear in Negin cultivar.