Lombardini spider mite

The Lombardini spider mite (Tetranychus lombardinii) is a significant agricultural pest belonging to the Tetranychidae family. Like other members of this genus, it is extremely small and often requires a magnifying glass to be identified in the field.

The adult mites typically measure between 0.3 and 0.5 mm in length. Their coloration can range from pale yellow to greenish-brown, often exhibiting distinct lateral dark patches. Adult females are generally larger and more robust than males.

The life cycle progresses through several stages: egg, larva, protonymph, deutonymph, and adult. Development speed is highly dependent on ambient temperature, with higher temperatures leading to rapid completion of the lifecycle.

The species survives the winter in a state of diapause as mated females, typically hiding in soil debris or protected cracks. They emerge to feed and reproduce as soon as environmental conditions become suitable in the spring.

A single female can lay a substantial number of eggs throughout her lifespan. This reproductive potential, combined with short developmental times, allows the mite population to reach outbreak levels within a short period.

Tetranychus lombardinii is a polyphagous pest, meaning it attacks a wide range of host plants, including various horticultural, field, and ornamental crops. It is known to cause damage to legumes, tomatoes, and other high-value crops.

Feeding occurs by piercing the plant tissue and extracting cellular contents. This mechanical damage disrupts photosynthetic activity and causes a loss of cellular turgor throughout the infested leaf tissues.

Initial symptoms include the appearance of small chlorotic stippling on the leaves. As the infestation progresses, these spots coalesce into large yellow or necrotic patches, leading to leaf drop and stunted plant growth.

The characteristic webbing produced by the mites on the underside of leaves and stems serves as a protection mechanism and facilitates the movement of the mites across the plant canopy.

In addition to direct physical damage, the stress caused by high mite density renders plants more susceptible to pathogens and can significantly reduce the overall yield quality and marketability.

Effective management requires an integrated approach that combines biological, cultural, and chemical tactics to maintain mite populations below the economic injury level.

Cultural practices, such as maintaining proper plant hydration and eliminating weed hosts around the fields, are essential for preventing early season population surges.

Biological control using predatory mites such as Phytoseiulus persimilis or Amblyseius species has proven to be highly successful, particularly in greenhouse conditions.

Chemical control involving acaricides should be used judiciously. To delay the onset of pesticide resistance, it is critical to rotate between products with different modes of action.

• Regular field scouting to monitor pest density.
• Thorough cleaning of equipment to prevent cross-contamination.
• Removal and destruction of heavily infested plant parts.