Andean root-lesion nematode

Systematic position. The Andean root-lesion nematode (Pratylenchus andinus) belongs to the phylum Nematoda, class Chromadorea, order Rhabditida, and family Pratylenchidae. It is a migratory endoparasite that colonizes the cortical tissues of host roots, causing localized necrotic lesions that eventually lead to the decay of the root system.

Host plants. The primary host of this nematode is the potato. It is particularly problematic in cool-temperate regions, where it impacts crop quality and total yield. While potato is its main target, the nematode is known to infest various solanaceous weeds and other crop species, which facilitates its persistence in fields even when the primary host is absent.

Biology and life cycle. Pratylenchus andinus undergoes several developmental stages, including an egg, four juvenile stages, and an adult stage. Both juveniles and adults are motile and capable of entering and leaving roots at any point along their length. Reproduction often occurs within the root cortex, where the nematodes feed on the cytoplasm of parenchymal cells, causing significant tissue destruction.

Damage patterns and economic importance. The presence of these nematodes is often signaled by reduced plant vigor, stunting, and chlorosis. The root damage creates entry points for other soil-borne pathogens.

• Necrotic lesions on tubers and roots.
• Disruption of water and nutrient uptake.
• Significant reduction in tuber size and marketability.
• Increased susceptibility to secondary rot-causing organisms.

Protection measures. Controlling Pratylenchus andinus requires an integrated approach. The most effective strategy is the use of nematode-free, certified seed tubers to prevent the introduction of the pest into clean fields. Cultural practices, such as extended crop rotation with non-host crops and the implementation of soil solarization or biofumigation using mustard crops, can significantly lower the nematode population density in the soil.