Computer simulation and population models for cyst-nematodes (Heteroderidae: nematoda)

Populations of plant-feeding soil nematodes are relatively immobile, slow to establish, much inbred and difficult to eradicate. Heterodera and Globodera spp, most of which lack effective enemies, increase fewer than 100-fold during a season and the number of generations passed can be limited by the short vegetative life of host crops. The problems of sampling field populations have been much studied and population structure is similar to that of other animals. Immigration and emigration are negligible so that population fluctuations can be investigated in pots or small field plots. The relationship between initial and final population densities during one growing season is described by an equation derived from the logistic equation which takes into account the damage caused to the root system by nematode attack and the fact that not all eggs hatch. Population oscillations are considered theoretically in relation to the modified logistic curve. Those of Globodera rostochiensis (Woll.)&nbsp