Evaluation of Dominus® (allylisothiocyanate) for tomato and bell pepper production

Dominus® (Isagro, USA), a newly registered biofumigant in the United States with active ingredient allylisothiocyanate (AITC), is currently under evaluation for use as a pre-plant soil treatment for both conventional and organic crop production. In recent field trials, Dominus provided root-knot nematode control in ornamental crops equivalent to that achieved with methyl bromide, but had inadequate weed control. A series of factorial field trials were conducted to evaluate weed and disease control in which Dominus was compared to an experimental formulation of organic acids and an untreated control. These treatments were applied with or without registered herbicides for tomato and bell pepper production. Application of the biofumigant (280 L ha-1) resulted in lower incidence of bacterial wilt (Ralstonia solanacearum) of tomato and soil populations of root-knot nematodes (Meloidogyne spp.). There was no improvement in nutsedge control with soil treatments, but both herbicides (fomesafen and halosulfuron) were effective in reducing nutsedge germination. Yields of both bell pepper and tomato were greatest in Dominus-treated plots, regardless of herbicide application. Combining Dominus with an herbicide provided broad-spectrum control of pathogens and weeds. The active ingredient AITC has well established potential as a biofumigant and the availability of a commercial formulation that can be combined with labeled herbicides provides a greatly needed pest control option.