Mexican spider mite

Systematic position: Tetranychus mexicanus belongs to the phylum Arthropoda, class Arachnida, order Trombidiformes, and family Tetranychidae. It is a highly specialized mite species known for its ability to cause significant agricultural losses in tropical and subtropical climates.

Host plants: This pest is known for its wide host range. It primarily attacks economically important crops such as citrus trees, grapevines, cocoa, and coffee plants. Furthermore, it can thrive on various vegetable crops and weeds, which often serve as reservoirs for the pest when the primary host crops are not available.

Biology and life cycle: The life cycle of Tetranychus mexicanus consists of an egg, larva, two nymphal stages (protonymph and deutonymph), and the adult stage. The speed of development is highly dependent on temperature and humidity, with hot and dry conditions accelerating the generation turnover. The mites typically reside on the undersides of leaves, constructing fine, silk-like webs to protect their colonies.

Damage and pest status: The feeding activity involves piercing leaf tissues and extracting cellular sap. Initial damage appears as small, pale chlorotic spots on the leaf surface. As the population increases, these spots expand, leading to leaf yellowing, necrosis, and eventual leaf abscission. Heavy infestations drastically reduce the photosynthetic capacity of the plants, resulting in stunted growth and significant crop yield losses.

Control measures: Integrated Pest Management (IPM) is essential for effective control. Key strategies include:

• Frequent field scouting to detect early signs of infestation.
• Biological control using predatory mites, such as those from the Phytoseiidae family.
• Application of selective acaricides when population thresholds are exceeded.
• Implementing cultural practices, such as maintaining plant vigor and managing weeds that serve as alternate hosts.