POPULATION DYNAMICS OF GLOBODERA PALLIDA UNDER POTATO MONOCULTURE

Abstract

Globodera spp. are under strict quarantine in many countries. Quarantines can hamper international trade, restrict the exchange and transport of agricultural goods, and require comprehensive in-state regulatory efforts. Often, the development of soil suppressiveness to cyst nematodes under monoculture of susceptible hosts is observed. In this research, the development of soil suppressive to Globodera pallida was evaluated over a 5-yr monoculture of susceptible potato in soil infested with G. pallida Pa3. Microplots infested with cyst nematode populations “Chavornay” or “Delmsen” were continuously cropped with susceptible potato ‘Selma’. Final cyst populations did not increase from 2010 to 2014. Final populations of total eggs remained similar for Delmsen but oscillated for Chavornay. This dynamic was also observed in the multiplication rate of cysts and total eggs of both nematode populations. Multiplication rates of cysts decreased by 60% for the Delmsen population. In both nematode populations, final proportions of diseased eggs increased in 2010 and oscillated until 2014, especially for Chavornay. This suggested a predator-prey relationship of the nematode and a suppressive factor. Yields of total marketable potato tubers increased in Chavornay but decreased in Delmsen. In this first report, numerical changes of cysts and diseased and healthy eggs of G. pallidaunder a potato monoculture were monitored. It remained unclear if organisms interfered with nematode activity, and if these could be beneficial in reducing the risk for nematode damage in potato production.