Northern root-knot nematode

Systematic position. The northern root-knot nematode Meloidogyne hapla is classified within the order Tylenchida and the family Meloidogynidae. It is a sedentary endoparasite that spends most of its life cycle within the root tissues of host plants, causing significant economic losses.

Host range. This species is highly polyphagous, capable of infecting over 500 species of plants. It is particularly destructive to vegetable crops like carrots, lettuce, onions, and potatoes, as well as perennial crops like strawberries. Its ability to survive in cooler climates makes it a widespread threat in temperate regions.

Biology and life cycle. The life cycle begins when eggs are laid in a gelatinous matrix within or on the root surface. Second-stage juveniles (J2) hatch and migrate through the soil to find new roots. Once they penetrate the root, they establish a feeding site, induce the formation of giant cells, and undergo several molts before reaching the adult stage.

Damage and economic impact. Infested plants show symptoms of nutrient deficiency, such as yellowing and wilting, due to a compromised root system. The hallmark of Meloidogyne hapla is the formation of small, irregular galls accompanied by excessive lateral root development, often referred to as a "hairy root" appearance, which renders root vegetables unmarketable.

Management strategies. Effective management integrates several approaches:

• Implementation of long-term crop rotation with non-host or antagonistic crops.
• Use of certified nematode-free planting material and resistant cultivars.
• Soil solarization and steam sterilization in greenhouses.
• Application of biological control agents, such as nematode-trapping fungi.
• Strict hygiene measures to prevent the spread of infested soil via equipment.