Title: Chemical control of nematodes: efficiency and side-effects
Headings: Chemical control of nematodes: efficiency and side-effects
Chemical control of nematodes: efficiency and side-effects
S.R. Gowen
Introduction
Chemical control of nematodes
The demand
Efficacy
TABLE 1
Nematicides currently available on world markets
TABLE 2
Examples of recommended nematicidal dosages and treatments for some important crops1
Side-effects
Future developments
References

Content: Compounds releasing methyl isothiocyanate (dazomet, metam-sodium) work best in soils at >15°C. In cooler soils, the period between treatment and planting may have to be extended to allow sufficient time for the product to disperse. The liquid fumigant DBCP is the only volatile compound that can be applied to growing plants without causing phytotoxicity. However, its manufacture has now ceased for toxicological reasons and its use is banned in many countries. Non-volatile nematicides. A number of organophosphate and oximecarbamate nematicides were developed in the 1960s, which had the advantage that application was relatively simple (Wright, 1981). As a consequence nematicide use became more widely practised. These compounds (Table 1) are active at dosages of 2 to 10 kg a.i./ha which are smaller than the 200 to 300 litres/ha required for treatment with liquid fumigants. Most of the early formulations of these products were as granules that, when applied to the soil surface (or preferably incorporated in the top 10 cm of soil), release the active ingredient, which is spread through the soil by rainfall or irrigation. The efficacy of soil penetration depends on the amount of moisture, organic matter and soil structure.