Population dynamics and interactions between plant parasitic and non-parasitic nematodes: An empirical analysis

Non-linear regression models were used to estimate the effect of own and other taxa previous population levels, nitrogen application, and crop rotation on population dynamics of Mononchidae, Dorylaimidae, microbivorous (Rhabditidae), lance (Hoplolaimus galeatus), spiral (Helicotylencus dihystera), stubby root (Paratrichodorus minor), lesion (Pratylenchus zeae), and cotton root-knot (Meloigogyne incognita) nematodes using data from the Cullars rotation, which is the oldest soil fertility experiment in the Southern United States. Because field experimental data was used, a spatial component was included as populations in one plot were proved to be related to the population level of their neighbors. Own previous levels were found to be very important for all eight groups of nematodes (all groups’ current population relied heavily on its own previous population value) and all the groups had an interaction effect with at least one other group. Lesion and cotton root-knot nematodes were found to be competitive while Mononchidae, Dorylaimidae, microbivorous and lance nematodes were non-competitive. All the populations showed high seasonality patterns having lower populations during winter, to then remain steady until September–October when there is a significant increase in the population of cotton root-knot, Dorylaimidae, microbivorous, and lesion nematodes. Nitrogen had a positive effect on Mononchidae, microbivorous, spiral, and cotton root-knot nematodes. The use of clover after cotton in the rotation crop program proved to be significantly better in reducing plant parasitic nematodes compared to other treatments.