Paecilomyces lilacinus (Purpureocillium lilacinum)

Introduction

Paecilomyces lilacinus, now renamed Purpureocillium lilacinum, is a beneficial fungus used for the biological control of plant-parasitic nematodes. It is especially effective against root-knot nematodes (Meloidogyne spp.), lesion nematodes, and cyst nematodes, which cause serious yield losses in a wide range of crops. It provides a sustainable and eco-friendly alternative to toxic nematicides.

Scientific Description

Purpureocillium lilacinum is a filamentous soil-dwelling fungus from the family Ophiocordycipitaceae. It colonizes nematode eggs, juveniles, and sometimes adults, penetrating their bodies and parasitizing them. The fungus is also saprophytic and can survive in soil without a nematode host by feeding on organic matter.

Mechanism of action:

• Egg Parasitism: Penetrates and colonizes nematode eggs, preventing hatching.
• Juvenile Infection: Infects second-stage juveniles (J2) of root-knot nematodes in soil.
• Enzymatic Degradation: Produces chitinases, proteases, and lipases to dissolve nematode protective layers.
• Soil Persistence: Survives in organic-rich soils, colonizes rhizosphere, and suppresses nematode populations over time.

Benefits

• Reduces Nematode Populations: Directly targets eggs and juvenile stages of damaging nematodes.
• Safe and Non-Toxic: Environmentally benign; does not harm beneficial nematodes or soil fauna.
• Improves Root Health: Leads to fewer root galls and improved nutrient uptake.
• Shelf-Stable: Can be formulated as powder or liquid for various application methods.
• Long-Term Control: Colonizes root zones for season-long suppression under good soil conditions.

Uses

• Target Nematodes: Root-knot (Meloidogyne), cyst (Heterodera, Globodera), lesion (Pratylenchus), and reniform (Rotylenchulus) nematodes.
• Crops: Tomato, brinjal, chili, cucumber, banana, turmeric, ginger, sugarcane, cotton, pulses.
• Application Methods:
  • Soil application: 2–5 kg/acre (talc-based) or 1–2 L/acre (liquid), applied with compost or FYM
  • Nursery treatment: 10–20 g per kg nursery media or 5 g per tray
  • Root dipping: For transplants and banana suckers (5 g/L water)
• Timing: Apply 7–10 days before transplanting, or at early growth stages for best results
• Environmental Preference: Moist, organic soils enhance fungal establishment and efficacy

Trivia

• Originally isolated from nematode-infected soils in tropical regions.
• Now part of commercial nematode management solutions in integrated pest management (IPM).
• The renaming to Purpureocillium was based on genetic studies separating it from true Paecilomyces species.
• Sometimes used alongside neem cake or Trichoderma to create a suppressive soil microbiome.