Plant growth and population dynamics

The main purpose of quantitative nematological research is to achieve an optimal economical protection of crops against plant-parasitic nematodes. To accomplish this, the costs of control measures must be adjusted to the costs of the expected yield reduction compared to the yield in a situation without the need for control. Such an adjustment requires quantitative knowledge of: (1) the relationship between a measure for the nematode activity (in practice mostly their population density at the time of planting) and plant response; (2) the population dynamics of nematodes in the presence of food sources (of different quality) and in the absence of food; (3) the effect of control measures on plant response and nematode population dynamics; the control measures may range from pesticide treatment, crop rotation and cultivation of crops that vary in suitability as a food source for nematodes; and (4) cost/benefit of the control measures. Some of these aspects are discussed in this chapter.