## Abstract

A two-year soil sampling study was conducted on four microplots naturally infested with Heterodera glycines and an undescribed species of Pasteuria. The objectives of the study were to investigate the population dynamics of both organisms and to assess the potential of Pasteuria sp. as a biological control agent of H. glycines. Seasonal fluctuations were observed in numbers of cysts, eggs per cyst, second-stage juveniles (J2) of H. glycines, number of Pasteuria endospores attached per J2, and percentages of endospore-encumbered J2. Percentages of endospore-encumbered J2, Y, increased with the mean numbers of endospores per J2, X, according to the equation Y = 87.0(1 - e^{-0.53X}). In contrast, numbers of J2 per 250 cm^{3} soil, Y, decreased with the numbers of endospores per J2, X, according to the exponential decay model Y = 67.4 + 220.1e^{-1.2X}. The equilibrium J2 density (67.4 ± 3.3) derived from this function was consistent with the predictions of the Lotka-Volterra model of population dynamics based on the equation 0.01951n(y) - 0.000336y = 0.000049x - 0.002851n(x) + 0.06589, where x and y represent the biweekly means of J2 densities and the percentages of endospore-encumbered J2, respectively. In all cases, predicted equilibrium densities of J2 were below the damage threshold reported from field studies. These results indicate that, given sufficient time following introduction into a field, Pasteuria may increase to levels that would be effective as one component in an integrated pest management program to control H. glycines.

Original language | English (US) |
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Pages (from-to) | 81-92 |

Number of pages | 12 |

Journal | Journal of Nematology |

Volume | 30 |

Issue number | 1 |

State | Published - Mar 1998 |

## Keywords

- Biological control
- Glycine max
- Heterodera glycines
- Modeling
- Nematode
- Pasteuria
- Population dynamics
- Soybean
- Soybean cyst nematode

## ASJC Scopus subject areas

- Agronomy and Crop Science