Coffee rhabditid nematode

Systematic position. Rhabditis coffeae belongs to the phylum Nematoda, class Chromadorea, order Rhabditida, and family Rhabditidae. While many nematodes in this group are saprophagous, this species is noted for its ability to infest plant tissues, particularly in moist soil environments where coffee plants are cultivated.

Host plants and damage. The primary host for this nematode is the coffee plant (Coffea spp.). The parasite invades the root system, causing necrotic lesions and root decay. This disruption of the root architecture leads to systemic plant stress, manifested as yellowing of leaves (chlorosis), stunted growth, and in severe cases, the eventual decline and death of the plant.

Biology and life cycle. The life cycle consists of egg, juvenile, and adult stages. The nematodes thrive in moist substrates with high organic matter content. A critical biological aspect is the formation of dauer larvae, an arrest-stage that allows the nematode to survive harsh conditions and persist in the soil until more favorable host conditions return.

Harmfulness. The economic impact of Rhabditis coffeae is significant, particularly in nursery settings. By damaging the physical integrity of the roots, the nematode facilitates the entry of soil-borne fungi and bacteria, which often act as co-pathogens, leading to complex root rot diseases that are difficult to treat once established.

Control measures. Effective management strategies include:

• Strict quarantine and inspection of planting stock before introduction to the field.
• Soil solarization or steaming for nursery soil to reduce initial nematode populations.
• Enhancement of soil biodiversity by adding organic amendments that favor nematode-suppressive microbes.
• Strict water management to avoid waterlogging, which is a major driver for the proliferation of this pest.