Integrated management of Globodera rostochiensis: a novel biocontrol agent, crop rotation and fallow

Abstract

A major problem for potato production worldwide is Globodera rostochiensis. Field control of this nematode is difficult because of the high reproductive rate of this genus and its resistance to biotic and abiotic factors. Biological control of nematodes is an increasingly popular strategy because it is effective and has low environmental impact. In this study, the potential of the nematophagous fungus Metarhizium carneum to mitigate the G. rostochiensis population in the presence of a susceptible potato host without previous management and during two crop cycles was evaluated, which included cultivation of the non-host faba bean followed by a susceptible potato crop. The effect of M. carneum application to the soil allowing the field to remain fallow for 2 years was also evaluated. Although M. carneum reduced the G. rostochiensis population by 33% during one potato crop cycle, the yield did not increase. With the application of M. carneum and a faba bean/potato rotation, the nematode population in the soil was reduced by 81%, with a significant increase in yield. Likewise, the use of the fungal biological control agent and the fallow period resulted in an 87% reduction in the nematode population after 2 years. Additionally, Rhizoctonia solani damage in tubers to which M. carneum was applied was lower than that in non-treated tubers in both experiments. The reduction in the population density of G. rostochiensis without the application of the biological control agent, including in the crop rotation and fallow treatments, was very low in both experiments. The combination of two management strategies, such as the use of biological control and crop rotation or a fallow period, may be a viable approach for the integrated management of G. rostochiensis in areas where high densities of this nematode occur.