Citrus nematode

The citrus nematode (Tylenchulus semipenetrans) is a significant plant-parasitic nematode responsible for causing slow decline in various permanent crops. It is classified as a semi-endoparasite, where the female head remains embedded in the root cortex while the body remains outside.

This parasite primarily targets citrus trees (Citrus species) and is also a known threat to grapevines. It specifically feeds on the cortical cells of the root system, which disrupts the uptake of nutrients and moisture, eventually leading to reduced tree vigor and significant yield losses.

Symptoms are often subtle and develop slowly, making early detection difficult. Affected plants show signs of nutrient deficiency, chlorosis, reduced leaf size, and overall stunting. In mature orchards, severe infestations cause twig dieback and a gradual decline in fruit size and commercial quality.

Environmental conditions such as warm, well-aerated soils are ideal for the development and spread of Tylenchulus semipenetrans. The nematode is primarily dispersed through the movement of infested soil on machinery, equipment, and, most importantly, through the planting of infected nursery stock.

Management strategies focus heavily on prevention, starting with the use of nematode-free certified seedlings. In established orchards, integrated pest management (IPM) is essential, including the use of targeted nematicides, maintaining high soil organic matter levels, and ensuring proper irrigation and fertilization to help the plant tolerate root damage.

• Root system decay
• Decline in fruit production
• Slow tree exhaustion
• Soil-borne transmission