Population Dynamics and Damage Potential of Belonolaimus sp. on Corn

The population dynamics and damage potential of an undescribed species of Belonolaimus were investigated for 2 years in a naturally infested commercial corn field in southwestern Kansas and for a third year in a field microplot study. Population trends and vertical distribution of nematode life-stages were monitored and relationships between corn yields and initial or midseason nematode population densities were described using regression analyses. Nematode populations in field plots and in the top 30 cm of microplots increased following seedling emergence, then declined steadily. Numbers of adult nematodes remained relatively stable in all studies, but shifts were observed in the vertical distribution of females in microplots. Females and juveniles in microplots were concentrated in the upper 30 cm of soil 3 weeks after planting but were below normal sample depths by mid-July. Corn yields decreased linearly with increasing initial and midseason nematode population densities.