Diseases Caused by Nematodes on the Sugar Beet

Abstract

Nematodes are one of the most abundant multicellular organisms in the world. A group of these soft-bodied roundworms, called plant-parasitic nematodes (PPN), can parasitize plants and cause serious damage. Most PPN are soil-borne pests and can cause yield loss by feeding on the root tissue of host plants and depriving them of nutrients and water. Annual worldwide crop losses due to PPN have been estimated to range from 8.8 to 14.6%. However, the severity of yield losses caused by PPN can vary with the species present in the fields. Among the numerous species of PPN that infest sugar beet fields, sugar beet cyst nematode (SBCN) and stubby root nematode (SRN) are two of the more economically important groups for sugar beet growers. The above-ground symptoms caused by these PPN mimic the symptoms caused by other biotic diseases and abiotic stresses. Below the ground, tiny lemon-shaped white to yellow adult SBCN females can be seen on SBCN-infected roots. Feeding of SRN on taproot and lateral root tips causes the roots to get swollen, giving the roots a stubby-ended appearance. Effective management of PPN relies on an integrated approach that focuses on preventing the introduction of PPN into an un-infested field and reducing their reproduction in infested fields using strategies such as crop rotation and host resistance. Since effective management tactics can vary with the species present in the fields, sampling and diagnosis are critical. Through such proactive management strategies, yield losses caused by PPN can be reduced.