Biocontrol of Tomato Verticillium Wilt by Using Indigenous Gliocladium spp. and Penicillium sp. Isolates

摘要

Endogenous Gliocladium spp. and Penicillium sp. isolates were tested in vitro, in vivo and in situ for their antagonistic activity against Verticillium spp. causing tomato vascular wilt in Tunisia. Gliocladium catenulatum, G roseum and Penicillium sp.isolates reduced the radial growth of V. dahliae, V. albo-atrum and V. tricorpus in comparison to the untreated controls. Antagonistic potential of Gliocladium spp. and Penicillium sp. against tested wilt agents showed intra- and inter-specific variations. Additionally to the sclerotinization inhibitory activity and to the reduced abundance of resting structures of Verticillium spp. observed, compared to untreated controls, antagonists tested caused several alterations of Verticillium spp. mycelium atthe confrontation zone. The germination of V. dahliae microsclerotia, exposed for 30 min to liquid cultures of antagonists tested and incubated at 20°C, was completely suppressed compared to the control microsclerotia treated with sterile distilled water. Furthermore, germinating microsclerotia dual cultured with Gliocladium spp. and Penicillium sp. became inable to germinate and mature microsclerotia progressively lost their typical dark colour. All tomato cv. 'Ventura' plants, when treated at planting with Gliocladium spp. and Penicillium sp. spore suspensions and inoculated with V. dahliae, showed after 60 days of culture under growth chamber conditions, reduced severity of Verticillium wilt in comparison to inoculated and untreated control plants.Plants treated with antagonists tested showed increased height and root and stem fresh weights in comparison to the inoculated and untreated control. The discoloration index, noted on tomato plants treated at planting by G. catenulatum, G roseum and Penicillium sp. and grown under greenhouse conditions, was significantly reduced compared to the untreated control. Plants treated with Penicillium sp. showed, after 90 days of culture, an increase of more than 40% of their roots and stem fresh weights in comparison to the untreated control.