Evaluation of the efficacy of the plant-based fumigant Dominus in managing broadleaf and narrow-leaved weeds in onion (Allium cepa L.) cultivation

This study was conducted to assess the efficacy of the bio-herbicide Dominus (based on allyl isothiocyanate, applied at ۲۸۰ L ha⁻¹) for weed management in onion production under both greenhouse and field conditions in the southern region of Kerman Province, Iran, during the ۲۰۲۱–۲۰۲۲ growing season. In the greenhouse experiment, the effect of Dominus application on seven weed species was investigated using a factorial experiment with a completely randomized design and five replications. At the same time, the field trial was arranged in a randomized complete block design with two treatments, Dominus application and a non-treated control, with three replications. Under greenhouse conditions, Dominus significantly reduced germination of all seven weed species, including Malva neglecta Wallr., Amaranthus retroflexus L., Chenopodium album L., Lolium rigidum Gaud., Phalaris minor Retz., Avena ludoviciana Durieu., and Cuscuta campestris L. at the ۱% probability level. In the field, Dominus provided complete (۱۰۰%) control of the dominant weed Cyperus rotundus L. and markedly decreased the biomass of the other weed species. Onion yield in the Dominus-treated plots (۷۸ t ha⁻¹) did not differ significantly from the weed-free control (۷۹ t ha⁻¹). In contrast, the untreated weedy check exhibited an ۸۳% yield reduction, producing only ۱۵.۶۹ t ha⁻¹. However, Dominus® is a soil fumigant (allyl isothiocyanate) that poses specific, uncontrollable risks: off-target movement through air, high inhalation toxicity, requirement for complete protective gear (air-supplied respirators, chemical-resistant suits) and sophisticated closed-system injection equipment, and inherent unsuitability for open-field agriculture, especially near human dwellings. Therefore, despite its pronounced efficacy, the application of Dominus® is not advisable for onion production in the studied region or any open-field setting, and its use should not be recommended.

کلیدواژه ها:

Allyl isothiocyanate ، Biofumigant ، seed bank ، Soil fumigant