Application of an entomopathogenic fungus (Beauveria bassiana) increases potato nematodes reproduction and potato tubers damage caused by Ditylenchus destructor and D. dipsaci

Two greenhouse experiments were conducted to investigate the influence of Beauveria bassiana inoculated in the soil together with potato tuber rot nematode (Ditylenchus destructor) and stem and bulb nematode (Ditylenchus dipsaci). Data on nematode reproduction and consequently damage caused on potato tubers by these nematodes was investigated. In both experiments, the growing medium was inoculated with B. bassiana singly or in combination with D. destructor or D. dipsaci. B. bassiana alone did not negatively influence potato growth or tuber development. However, when B. bassiana was inoculated together with nematodes, higher nematode reproduction and tuber damage was observed at the end of the experiments. Tuber numbers and above ground fresh weight were not influenced by nematodes or a combination of B. bassiana and nematodes. Tuber weight was significantly reduced when nematodes were present together with B. bassiana. Although B. bassiana is an effective bio-control agent against some Meloidogyne spp., the application B. bassiana strain Naturalis in the presence of D. destructor and D. dipsaci might result in a detrimental interaction leading to higher nematode population densities and higher potato tuber damage.