Dosage of nematicidal fumigants and mortality of nematodes

Abstract

Results of field experiments reported in the literature suggest a linear relation between log dosage of dichloropropene injected into the soil and probit mortality of plant parasitic nematodes. In most cases probit mortality increases by about half a unit per doubling of the dosage of fumigant. This is in accordance with the distribution of sums of concentration-time (CT) products for dichloropropene in the soil according to investigations by Leistra (1971 and in litt.). The relation between log dosagex of the chemical and probit mortalityy can be described by the equationy=ax+b (a andb constants). Fora the name dosage increase efficiency is proposed. It is to be expressed in probit units per doubling of the dosage. The way in which the chemicals spread through the soil can be derived from the relation between dosage and mortality. Experiments should therefore always be done with a fairly large range of dosages including some of which only little effect is expected.