### Abstract

Original language | English |
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Title of host publication | Proceedings of the 67th International Symposium on Crop Protection |

Place of Publication | Ghent |

Pages | 21-21 |

Publication status | Published - 2015 |

Event | 67th International Symposium on Crop Protection - Duration: 19 May 2015 → 19 May 2015 |

### Conference

Conference | 67th International Symposium on Crop Protection |
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Period | 19/05/15 → 19/05/15 |

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### Cite this

*Proceedings of the 67th International Symposium on Crop Protection*(pp. 21-21). Ghent.

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*Proceedings of the 67th International Symposium on Crop Protection.*Ghent, pp. 21-21, 67th International Symposium on Crop Protection, 19/05/15.

**Survival and vitality of J2 of meloidogyne chitwoodi in time in pot experiments.** / Teklu, M.G.; Been, T.H.; Schomaker, C.H.; Beniers, J.E.

Research output: Chapter in Book/Report/Conference proceeding › Abstract › Academic

TY - CHAP

T1 - Survival and vitality of J2 of meloidogyne chitwoodi in time in pot experiments

AU - Teklu, M.G.

AU - Been, T.H.

AU - Schomaker, C.H.

AU - Beniers, J.E.

PY - 2015

Y1 - 2015

N2 - Survival in time of inoculated juveniles of Meloidogyne chitwoodi (J2) in the absence of host and their vitality on a susceptible host was studied in a pot experiment under glasshouse conditions. This is, to assess if part of the Pi can survive and become part of the Pf at harvest and affect the partial resistance estimator when testing for resistance. In total 96, 2 kg pots were filled with soil, brought to 10-12% moisture content, and a nematode density (Pi) of = 55.4 J2 g-1 dry soil was added. Immediately after inoculation, at time (t = 0) and weekly, during 15 weeks, batches of 6 pots were used to collect a 500 g sub-sample, which were elutriated using the Seinhorst elutriator to estimate the number of surviving nematodes. The remainder of the soil from each batch (1.5 kg) was stored at 4°C and used to check the vitality of the surviving J2 on the susceptible tomato cv. Moneymaker. The actual average recovery at (t = 0) after inoculation was 35.05 J2 g-1 dry soil indicating a loss of about 37%. Juveniles of M. chitwoodi could be recovered during all 112 days, although population densities dropped drastically to 0.44 J2 g-1 dry soils. The data of the surviving juveniles in time fitted well to an exponential model (R2 = 0.98). According to the model the daily mortality was 10.72% and 0.73% of the nematodes at time zero survived for 112 days. The initial loss of 37% of the inoculum is the result of losses during inoculation, mortality during mixing and reduction in elutriation. The efficiency of the Seinhorst elutriator for M. chitwoodi juveniles is 92%. When eliminating this error the actual loss declines to 31.23%. The largest percentage of this loss is mortality due to mixing of the soil before sub-sampling; a small percentage is lost during inoculation. Based on the decline data, the effect of the possible survival of inoculated juveniles on the estimator for partial resistance in pot tests can be calculated. The errors were researched both by simulation and by re-analysing some pot experiments with highly resistant potatoes genotypes and fodder radish varieties and will be discussed. In practice, the problem of surviving inoculated nematodes in pot experiments seems remote as a very large, if not the whole, of the volume of soil in the pot is rooted by the test plant and no J2 of the Pi will be available in the soil. The surviving nematodes from all ages were able to infect and multiply on the susceptible tomato cv. Moneymaker. The data obtained suggests two processes in this experiment: The first pattern shows a normal multiplication rate (a) of 11.2 and a maximum population density (M) of 43.2 J2 g-1 dry according to the population dynamics model at the highest nematode densities obtained in the first 29 days of the decline. A second pattern indicates a mortality of J2 in storage at 4°C as expressed in larger multiplication rates at shorter storage time at identical nematode densities. Key words: Population decline, multiplication, resistance testing and storage temperature

AB - Survival in time of inoculated juveniles of Meloidogyne chitwoodi (J2) in the absence of host and their vitality on a susceptible host was studied in a pot experiment under glasshouse conditions. This is, to assess if part of the Pi can survive and become part of the Pf at harvest and affect the partial resistance estimator when testing for resistance. In total 96, 2 kg pots were filled with soil, brought to 10-12% moisture content, and a nematode density (Pi) of = 55.4 J2 g-1 dry soil was added. Immediately after inoculation, at time (t = 0) and weekly, during 15 weeks, batches of 6 pots were used to collect a 500 g sub-sample, which were elutriated using the Seinhorst elutriator to estimate the number of surviving nematodes. The remainder of the soil from each batch (1.5 kg) was stored at 4°C and used to check the vitality of the surviving J2 on the susceptible tomato cv. Moneymaker. The actual average recovery at (t = 0) after inoculation was 35.05 J2 g-1 dry soil indicating a loss of about 37%. Juveniles of M. chitwoodi could be recovered during all 112 days, although population densities dropped drastically to 0.44 J2 g-1 dry soils. The data of the surviving juveniles in time fitted well to an exponential model (R2 = 0.98). According to the model the daily mortality was 10.72% and 0.73% of the nematodes at time zero survived for 112 days. The initial loss of 37% of the inoculum is the result of losses during inoculation, mortality during mixing and reduction in elutriation. The efficiency of the Seinhorst elutriator for M. chitwoodi juveniles is 92%. When eliminating this error the actual loss declines to 31.23%. The largest percentage of this loss is mortality due to mixing of the soil before sub-sampling; a small percentage is lost during inoculation. Based on the decline data, the effect of the possible survival of inoculated juveniles on the estimator for partial resistance in pot tests can be calculated. The errors were researched both by simulation and by re-analysing some pot experiments with highly resistant potatoes genotypes and fodder radish varieties and will be discussed. In practice, the problem of surviving inoculated nematodes in pot experiments seems remote as a very large, if not the whole, of the volume of soil in the pot is rooted by the test plant and no J2 of the Pi will be available in the soil. The surviving nematodes from all ages were able to infect and multiply on the susceptible tomato cv. Moneymaker. The data obtained suggests two processes in this experiment: The first pattern shows a normal multiplication rate (a) of 11.2 and a maximum population density (M) of 43.2 J2 g-1 dry according to the population dynamics model at the highest nematode densities obtained in the first 29 days of the decline. A second pattern indicates a mortality of J2 in storage at 4°C as expressed in larger multiplication rates at shorter storage time at identical nematode densities. Key words: Population decline, multiplication, resistance testing and storage temperature

M3 - Abstract

SP - 21

EP - 21

BT - Proceedings of the 67th International Symposium on Crop Protection

CY - Ghent

ER -