Biofumigation To Manage Plant-Parasitic Nematodes

Abstract

Abstract. Biofumigation is a sustainable strategy to manage soil-borne pathogens, nematodes, insects, and weeds. Initially it was defined as the pest suppressive action of decomposing Brassica tissues, but it was later expanded to include animal and plant residues. Most data on the efficacy of biofumigation are from in vitro studies using fungal pathogens. Biofumigation also attracted the interest of nematologists, and research on the potential of this method to manage plant-parasitic nematodes is reviewed. 1. INTRODUCTION Annual yield losses on a worldwide scale that are attributed to plant-parasitic nematode are estimated to range between 5% and 12% (Sasser & Freckman, 1987). Depending on climate, crops grown, nematode species and their density levels, and economic factors, a number of tactics can be employed to minimize nematode damage. Preventing the introduction of nematodes with planting material, seeds, or soil, including non-host crops in rotation schemes, using nematode resistant varieties or rootstocks, and lowering nematode populations through nematicides are some of the most frequently used strategies. However, concerns about the negative impact of synthetic nematicides on the environment and on general public health led to a re-evaluation of these products. For example, high use of the soil fumigant methyl bromide and resulting contamination of ground, surface and drinking water in The Netherlands led to a ban on its use in the 1980's (Mus & Huygen, 1992). Later, methyl bromide was listed as an ozonedepleting compound at the 4th meeting of the Montreal Protocol in Copenhagen, 1992, and in accordance with the US Clean Air Act its use as a fumigant is now banned in several nations. Methyl bromide was previously used as a pre-plant broad-spectrum soil fumigant to control soil-borne diseases, nematodes, insects and weeds in high value crops such as tomato, strawberry, cucurbits, nursery crops, flowers. It was also used to avoid re-plant problems in vineyards and orchards (Rodríguez-Kábana, 1997). With the disappearance of nematicides or restrictions on their allowed use, the interest in the development of safe, sustainable, and economically viable nematode management strategies has increased. One such a strategy that potentially fulfills