Impact of quarantine procedures on weed biodiversity and abundance: Implications for the management of the golden potato cyst nematode, Globodera rostochiensis

Abstract

In 2006, the golden nematode, Globodera rostochiensis, a regulated pest causing heavy losses in potato fields was discovered in Quebec, Canada. The rapid application of quarantine measures by the Canadian Food Inspection Agency significantly changed the use and management of infested fields. The objectives of this study were to assess the evolution of weed populations following these measures and assess their impact on the management of G. rostochiensis. A comparison of weed inventories conducted in 2008 and 2011 on the edges of the affected fields has shown that the composition of the flora had changed considerably. Alarmingly, the presence of Solanaceae that could potentially serve as host plants for the potato cyst nematode increased significantly. The biodiversity index was also significantly affected by this change and decreased by more than 50% between the two years. Interestingly, the lowest biodiversity was observed in one of the few fields where potatoes were grown in 2011 and where an explosion of Solanum sarrachoides was observed. Meanwhile, eight species of nightshade were evaluated for their ability to support the growth of G. rostochiensis. Solanum villosum allowed the greatest rates of reproduction while only a few cysts were produced on Solanum nigrum and Solanum dulcamara. This study has shown that the modifications in weed control regimes associated with the implementation of quarantine procedures could hamper its success by favouring the multiplication of potential pest refuges.