The Effect of Nitrogen Deficiency On the Growth of Meloidogyne Javanica At Different Population Levels

Abstract

The rates of growth of M. javanica at different population levels have been measured in tomatoes grown on either full nutrient or in the absence of nitrogen. At low inoculation levels (40 larvae/plant) there is an acceleration of growth in nitrogen deficient plants. At higher inoculation levels (400 larvae/plant) this rate of growth declines and is significantly less than in plants grown on full nutrient. At higher inoculation levels (4000 larvae/plant) the rates of growth of the nematodes in both treatments is considerably reduced. Males were found in the treatments in which the ratios of number of nematodes in inoculum per gram of fresh weight of plant were highest. At the highest inoculation levels the nematodes significantly influenced the rates of growth of tomato plants grown either on full nutrient or in the absence of nitrogen, although this was more pronounced in the absence of nitrogen. The hypothesis is advanced that the rate of growth of M. javanica is related to the degree of stress to which it is subjected. A little stress leads to an acceleration in the rate of growth and further stress leads to the production of males and a slowing down of the overall rate of growth of the particular population under consideration.