Biology and Epidemiology

- Survival and sources of inoculum

Eggs and young larvae, protected within the cysts can survive several years in the soil in the absence of host plants. The cysts (figure 1) are structures  able to withstand drought and the effects of some chemical nematicides. The genus Globodera infects a small number of hosts including other Solanaceae.


- Penetration into the plant and invasion

When the weather conditions are favourable, the young larvae, attracted by  root exudates, migrate and penetrate into roots and central cylinder. The larvae become either males or females. The latter gradually produce eggs, while adult males return back to the soil. The body wall of females will harden and become cysts.


- Dissemination

The cysts finally detach from the roots and many young larvae are released from them (figures 2 and 3). They spread to other roots. They can be disseminated passively by water runoff, drainage and irrigation. Other possible ways of dissemination are by dust from contaminated soil, carried by wind to neighboring crops. Infected plants, farming equipment, or vehicles, may also disseminate the pathogen.


- Favourable conditions for nematode development

Favourable conditions are not well known for Globodera tabacum.