Two-spotted spider mite

The two-spotted spider mite (Tetranychus urticae) is a member of the Arachnida class, Trombidiformes order, and Tetranychidae family. It is a highly polyphagous pest known to infest a vast array of agricultural, horticultural, and ornamental plants globally, thriving particularly well in protected cropping systems.

The biological cycle of this pest is rapid, heavily influenced by temperature and humidity. Under hot and dry conditions, the life cycle from egg to adult can be completed in less than a week. Females overwinter in soil debris or greenhouse structures, emerging in spring to initiate new colonies that grow exponentially if left unchecked.

Mites cause damage by piercing leaf tissues and extracting cellular contents, which disrupts photosynthesis and stunts plant growth. Early signs include tiny chlorotic spots or stippling on the leaves. As the infestation progresses, leaves lose their green color, turn yellow or bronze, and eventually desiccate, leading to significant yield loss.

Visual identification of the pest is often based on the presence of fine silk webbing produced on the undersides of leaves, which serves as protection and a structural base for colonies. Because they are so small, growers often do not notice the infestation until damage is widespread, highlighting the critical need for early detection and scouting.

• Monitor crops regularly using magnifying glasses.
• Increase relative humidity in greenhouses to hinder mite development.
• Introduce predatory mites like Phytoseiulus persimilis for biological control.
• Rotate specific acaricides to prevent the development of pesticide resistance.
• Remove and destroy severely infested plants to reduce the local population.

Effective management requires an Integrated Pest Management (IPM) approach. Combining environmental manipulation, biological control agents, and judicious use of chemicals ensures that the population of the two-spotted spider mite remains below the economic threshold without causing excessive harm to beneficial insects or the environment.