Management of accelerated microbial degradation of nematicides in Western Cape soils

The accelerated breakdown of nematicides when frequently applied to soil have been fairly well documented.  This process seriously affect or totally eliminate the efficacy of the nematicide.  Oxidation is the most common breakdown path and is mostly the result of soil micro-organism activity, from there the term “accelerated microbial degradation” or AMD.

AMD is a reality and can occur in any soil.  Once this degradation process has established itself in a soil it reduces the efficacy of nematicides significantly.

However, it is a complex phenomenen, with a number of factors involved, some of which are not yet fully understood.  These factors include pH, soil moisture, soil texture, and also the organisms responsible for the breakdown.  Due to our present lack of knowledge it is not yet possible to predict after how many nematicide applications AMD will occur in a specific soil, or to draw up a protocol to prevent AMD in all soils and in all situations.  The best that can be done at present is to make producers and technical advisors aware of AMD and its possible causes to aid in the decision-making process when deciding on nematicide use.