Stem nematode (Anguillidae)

They affect a wide range of host plants, including onions, garlic, potatoes, strawberries, and several ornamental bulbs. The nematodes enter the plant tissue through natural openings such as stomata or wounds, where they feed on the cell contents, leading to cellular degradation and tissue softening.

The biology of these nematodes is remarkable for their survival mechanism: they can enter a state of dormancy, known as anhydrobiosis, when conditions become dry or unfavorable. This allows them to persist in soil or dried plant debris for several years until moisture returns, facilitating the next infection cycle.

Symptoms of infestation vary by crop but generally involve stunting, swelling, and twisting of stems, as well as the 'bloating' or rotting of bulbs. In severe cases, the entire plant structure may become distorted, leading to poor yield and reduced shelf life of the harvest. Secondary fungal and bacterial infections often follow, complicating the damage.

Management strategies focus on sanitation and prevention. Key measures include rotating crops with non-host species for several years, ensuring that only nematode-free planting stock is used, and destroying infested plant material immediately. In some commercial settings, hot water treatment of bulbs is used to kill nematodes, while chemical nematicides may be applied in severe soil contamination cases.