1. RECOMMENDATIONS FOR THE KEY CROPS

Dazomet has been used to disinfect soils of many crops, although its effectiveness is limited or conditioned by the difficulties involved by a proper application (inconsistency processes). Moreover, the risks of accelerated degradation due to the repeated applications may be considered (Di Primo et al., 2003), being potentially reduced by adoption of other soil fumigants and/or combining with soil solarization.

Pepper

At rates of 60 g/m² in broadcast application, Dazomet has not been effective in controlling Phytophthora capsici and Meloidogyne incognita under greenhouse conditions (Ros et al., 2004). Additionally, the yields were small, not significantly different from non-treated controls. However, in the case of soils with low levels of pathogen infestation and without repetition of monocultures, the results are closer to those of MB. Dazomet applied after soil solarization reduced the impacts caused by Meloidogyne incognita in crops under plastic in Turkey, with yields not significantly different from MB (Sögüt and Elekcioglu, 2007).

Tomato

In the case of tomato growing under open air conditions, Dazomet applied in a concentration of 40 g/m², significantly reduced the incidence of Fusarium oxysporum, but did not reach the level of MB. The combination of Dazomet with the subsequent application of 1,3-Dichloropropene (1,3-D) + Chloropicrin (PIC) and PIC in pre-plant drip irrigation provided yields close to those obtained with MB (Nelson et al., 2002). The combination of a three weeks period of soil solarization with half dosage of dazomet proved very effective, in the presence of high disease incidence. Moreover the use of virtually impermeable plastic film (VIF) permitted to achieve higher temperatures in the case of solarization improving the efficacy of dazomet (Minuto et al., 2000).

Strawberry

The system of application seems to influence the effectiveness of control of nematodes, to level achieved with MB (López-Aranda et al., 2004). For weed control, it was similar to that of MB, both in the biomass production and in the time needed for weeding (López-Aranda et al., 2004). Random results were found when it is used in nurseries: similar number of useful plants per unit area in some plots while others resulted in a significant reduction The main problem of Dazomet efficacy, in the case of strawberry nurseries, has been the inconsistency effectiveness, probably due to the different conditions of fumigant application (Melgarejo et al., 2001). When Dazomet was combined with solarisation, results were improved, but did not reach the levels of yield and weed control than with MB (Yucel et al., 2002). However, it shows some effects on soilborne fungi such as Fusarium oxysporum, Rhizoctonia solani and Macrophomina phaseolina (Yücel et al., 2000). The authors also point out that the effectiveness is increased when, after the application, the soil is irrigated by a drip irrigation system. With other products its effectiveness disinfectant is improved, and the combination of 20g/m² of Dazomet with 20 g/m² PIC led to a proper control of weeds and yields (Shem-Tov et al., 2005 and 2006). Recently the utilization of Dazomet and MS as MB alternative for strawberry cultivation has been implemented (150-250 hectares) in the coastal area of Huelva (mainly by means of combination with 1,3-D).

2. RECOMMENDATIONS FOR OTHER CROPS

Dazomet was effective in controlling Fusarium oxysporum and Sclerotinia sclerotiorum in eggplant (Yücel et al., 2000). In onions and broccoli, Dazomet was as effective as MB and even better (Contreras and Krarup, 2002). As reported by the authors, the main problem is that Dazomet requires longer periods in the soil and ventilation than MB. More than a decade ago, the works carried out in potato in soils contaminated by Streptomyces scabies evidenced that Dazomet provided an increase in the number and weight of tubers compared to non-treated control (Alcalá de Marcano et al., 1993). For tests in cut-flower crops, Dazomet significantly reduced the viability of fungi as Pythium sp. Fusarium culmorum, Rhizoctonia solani, Sclerotinia sclerotiorum and Verticillium dahliae. Several authors such as Reuven et al. (2002, 2005), Elmore et al. (2003) evidenced Dazomet effectiveness in cut-flower crops production in Israel and USA. Finally dazomet applied alone or in combination with a 3 week period of soil solarization against Fusarium wilt on basil and Sclerotinia rot of lettuce, proved very effective in the presence of high disease incidence (Minuto et al., 2000).

It is advisable to avoid excessive rates of application and promote combinations with other soil disinfectants, or add beneficial organisms after disinfection with Dazomet. In fact, the combination with other fumigants, or sequential application of these disinfectants, can provide adequate control of soilborne pathogens and increase yield equivalent to that obtained with MB. In all cases, the application rates vary between 35 and 60 g/m² depending on the crop, pathogens and soil characteristics.

However, the combinations with 1,3-D and PIC and some herbicides complete the spectra of activity required by vegetable, ornamental and fruit industry. Moreover, Dazomet has recently been used in crops of lettuce and leafy vegetables in some regions of South-Eastern Spain, using mechanized incorporation and proper soil sealing.

For further information, you can visit the Dazomet page of the Alternatives section.

Writing Date : 2008-06-16
Latest update Date : 2008-06-16