Pygmy woodlouse

Systematic position. The Pygmy woodlouse (Trichoniscus pusillus) belongs to the order Isopoda, family Trichoniscidae. Unlike many other pests, this is a small terrestrial crustacean. It is highly sensitive to desiccation, which dictates its preference for humid microhabitats in greenhouse and nursery environments.

Affected crops. This pest primarily targets vegetable seedlings, ornamental flowers, and fungi in greenhouse systems. Vulnerable crops include young tomatoes, cucumbers, peppers, and various succulent greenhouse plants. They are frequently found where soil moisture remains high and organic debris is abundant.

Biology and life cycle. These crustaceans are nocturnal, hiding during the day in crevices, under containers, or within damp organic matter. They reproduce sexually, and the females carry developing young in a brood pouch. Their lifecycle is tied to stable, humid conditions, allowing populations to expand rapidly if greenhouse sanitation is poor.

Nature of damage and harm. Woodlice feed on tender plant tissues, including young shoots, roots, and the epidermis of leaves near the soil surface. Heavy infestations can cause significant stunting, reduced plant vigor, and total loss of young transplants. Furthermore, they can transport pathogens, contributing to the spread of soil-borne diseases.

• Maintain good ventilation to reduce overall greenhouse humidity.
• Clear all organic waste and debris from growing areas.
• Seal cracks and crevices in concrete floors or greenhouse foundations.
• Use physical barriers like copper tape or diatomaceous earth.
• Apply specific pesticides only when mechanical control proves insufficient.

Protection measures. Integrated Pest Management (IPM) is the best defense against the Pygmy woodlouse. The focus should be on environmental manipulation, such as ensuring proper drainage and keeping the growing area free of unnecessary materials that provide shelter. Reducing soil moisture around the base of plants is critical to limiting their movement.