Peanut pod lesion nematode

The causative agent of the condition known as pod lesion is the Tylenchorhynchus spp. nematode. These are ectoparasitic soil-dwelling microscopic roundworms that feed on the surface tissues of roots and the epidermis of developing legume pods while they are embedded in the soil.

The primary crop affected by this pathogen is peanut (Arachis hypogaea). The presence of these nematodes causes significant damage to the outer layer of the shells, which directly impacts the quality of the harvested yield and opens pathways for various opportunistic fungal pathogens.

Key symptoms observed include dark brown necrotic lesions, shallow pits, and cracks on the surface of the peanut pods. These lesions often coalesce, leading to severe discoloration and sometimes causing the shell to become brittle or soft, which facilitates decay and reduces marketability.

Environmental conditions that favor the development of Tylenchorhynchus include warm temperatures and adequate moisture. They thrive in light-textured soils, such as sandy loams, which provide the optimal porosity for nematode mobility and migration towards host plant organs.

Effective management and prevention strategies rely on integrated pest management practices. These include rotating peanuts with non-host crops, maintaining soil health, and performing soil analysis to monitor nematode populations. In cases of severe infestation, chemical nematicide application or soil solarization may be required to reduce the inoculum level in the field.