Efficacy of dimethyl disulfide (DMDS) against Meloidogyne sp. and three formae speciales of Fusarium oxysporum under controlled conditions

• Full nematicidal effect of DMDS for the doses used.
• Low rates of DMDS were sufficient for nematode control.
• Effectiveness differences were not observed in pot trials between the two types of films (PE and VIF).
• DMDS decreased significantly the inoculum density of Fusarium oxysporum.
• However, it was not enough to avoid the disease expression.

The efficacy of a soil disinfectant, dimethyl disulfide (DMDS), was assessed on known populations of different formae speciales of Fusarium oxysporum: F. oxysporum f. sp. radicis-lycopersici; F. o. f. sp. radicis-cucumerinum and F. o. f. sp. lycopersici and Meloidogyne nematodes. Two trials were carried out over two years (2012–2013), in a greenhouse under semi-controlled environmental conditions and in a growth chamber, in 3-L volume pots filled with sterile vermiculite. Two doses of DMDS (400 L ha−1 and 600 L ha−1) and two plastic covers: VIF (virtually impermeable film) and PE (transparent polyethylene) were tested. The results showed a full nematicidal effect for the two doses, without differences between the two types of plastic. The inoculum density of F. oxysporum was significantly decreased by DMDS, but expression of the disease was not prevented. The assessment of the phytotoxic effect on seed germination of lettuce showed that residual vapors of DMDS have a negative effect on seed germination in vermiculite.

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