The present practice of deep tillage in most horticultural cultivation, coupled with abundant organic fertilizer application, increased the nematode problem in the deep soil range (25-50 cm depth). For this reason, farmers had to use more nematicide than usual.

However, the use of synthetic chemicals in the fight against this pest is deemed undesirable by an increasing number of consumers. Consequently, the possible efficient use of the horse radish extract allyl isothiocyanate (AITC) in addressing this problem was studied.

　Tests had indicated that the performance of AITC as nematicide is comparable with the commercial nematicide DD. Especially in the case of AITC, a two-point injection method provided the best effectivity against　nematodes. Applying a total dosage of 10 L/10a at 12.5 cm and 27.5 cm depths of the soil layer effected nematode mortalities of at least 99%.

Furthermore, covering the soil surface with polypropylene vinyl sheet after nematicide application showed longer retention time and nematode mortalities. It is therefore recommended that a two-point injection style soil fumigator be developed for eventual use in this new nematode control method.