Two-spotted spider mite

The two-spotted spider mite (Tetranychus urticae) belongs to the order Trombidiformes and the family Tetranychidae. It is a highly destructive polyphagous pest known to colonize a vast range of plant species, posing a severe threat to both commercial agriculture and horticultural productions worldwide.

This pest affects a wide array of agricultural crops. Significant economic losses are frequently observed in:

• Fodder beet
• Winter oilseed rape
• Cabbage
• Cucumber
• Soybean
• Winter barley
• Hops
• Apple trees

The biology of the mite is characterized by rapid development and high reproductive potential. The life cycle comprises egg, larva, protonymph, deutonymph, and adult stages. Under hot and dry conditions, the lifecycle can be completed in as few as seven days, allowing for multiple generations to occur within a single growing season.

Damage is caused by feeding on the cell contents of leaf tissue. Initial symptoms include tiny stippling patterns on the underside of leaves, which eventually lead to chlorosis, necrosis, and premature defoliation. In severe cases, the characteristic silk webbing covers the foliage, significantly reducing the plant's photosynthetic capacity.

Control strategies must be integrated, combining chemical, cultural, and biological methods. Growers should utilize selective acaricides, ensuring rotation to manage resistance. Cultural practices, such as maintaining optimal irrigation to reduce dust and stress, along with the release of predatory mites like Phytoseiulus persimilis, are essential for successful management.