Peanut stem nematode

Systematic position. The peanut stem nematode (Ditylenchus arachis) belongs to the phylum Nematoda, class Chromadorea, order Rhabditida, and family Anguinidae. It is a highly specialized plant-parasitic nematode that predominantly targets peanut crops, causing significant economic losses in infested areas.

Host crops. The primary host for this pest is the cultivated peanut (Arachis hypogaea). While it shows high specificity, it can survive in various soil types and crop residues, posing a constant threat to peanut production in endemic regions where host plants are repeatedly grown.

Biology and life cycle. Ditylenchus arachis completes its life cycle within the host plant tissues. It uses its stylet to penetrate cells and extract nutrients, which leads to tissue disintegration. The nematode thrives in moist soil conditions and is capable of entering a latent state (anabiosis) to survive unfavorable environmental conditions, making it difficult to eradicate completely.

Damage and harmfulness. Infestation is characterized by dark, necrotic lesions on the pod shells and potential rotting of the inner kernels. Heavily infested pods become distorted and discolored, which significantly lowers the market value of the harvest. Furthermore, infested seeds act as a primary source of inoculum for the following cropping season.

Protection measures. Effective management of Ditylenchus arachis requires an integrated approach to reduce population levels in the field:

• Use of certified nematode-free seeds for planting.
• Implementation of long-term crop rotation with non-host plants to break the life cycle.
• Post-harvest deep tillage to incorporate and decompose crop residues.
• Application of appropriate nematicides in fields with a history of severe infestation.