Interspecific and intraspecific competition in the potato cyst nematodes Globodera pallida and G. rostochiensis

Abstract

The effects of interspecific competition between the potato cyst nematodes (PCN), Globodera pallida and G. rostochiensis, under variable population conditions were examined. PCN-susceptible potato cultivars were inoculated with single- and mixed-species populations of PCN. There was a significant difference in species multiplication between single- and mixed-species populations. Globodera rostochiensis multiplication in mixed-species populations was significantly lower than single-species populations. Density-dependent trials showed a significantly greater increase in multiplication of G. pallida at low inoculation densities relative to G. rostochiensis. These results indicate that G. pallida has a negative effect on G. rostochiensis populations and is the more successful species when competing. A staggered inoculation trial showed that the greater competitiveness of G. pallida was not wholly attributed to its later hatch. Globodera pallida outcompeted G. rostochiensis regardless of the timing of inoculation; however, G. pallida multiplication was lowest when plants were simultaneously inoculated with both species.

Arbuscular mycorrhizal fungal‐induced tolerance is determined by fungal identity and pathogen density

“…At the greatest PCN density treatment in our experiments (125 eggs/g soil), there was no effect by AMF on post‐harvest PCN cyst counts. A decrease in reproduction factor of PCN as infection densities increase is a reported phenomenon (Hearne et al, 2017; Joshi & Kumar, 2020) and could be due to limited root space, enhancing competition for infection sites (Fourie et al, 2010). At this PCN density, there was also a reduction of eggs produced per cyst, regardless of AMF presence, indicating that the host cannot support this level of PCN infection and that the nematodes potentially suffer from lack of nutrition.…”

Predicting potential global distribution and risk regions for potato cyst nematodes (Globodera rostochiensis and Globodera pallida)

“…The results from Kaczmarek et al showed a broader temperature range with a similar trend (i.e., 13–25 °C for pPCN and 15–27 °C for gPCN), and they also presented that when the temperature was over 25 °C pPCN hatched more efficiently than gPCN 61 . Noteworthy is that pPCNs may outcompete gPCNs in the mixed-species soil due to their faster and more significant multiplication 62 . The broader suitable temperature range for pPCN utilised in this study can also support its greater competitiveness than gPCN.…”