Two-spotted spider mites cause damage at all mobile life stages—larvae, nymphs, and adults—by feeding on plant sap. They are typically found on the underside of leaves, where they pierce individual plant cells and extract their contents. This feeding leaves behind empty, yellowed cells, which can create a speckled, yellow dot pattern visible even on the upper leaf surface.

As the infestation progresses, the cumulative cell damage reduces the plant’s ability to photosynthesize efficiently, increases water loss through transpiration, and leads to stunted growth. In severe cases, entire leaves may yellow and die, and if enough foliage is affected, the entire plant can succumb. In crops like tomatoes and cucumbers, even 30% leaf damage can result in total crop loss.

In addition to feeding damage, nymphs and adults produce dense webs that can cover entire plants, further affecting plant health and significantly reducing visual quality—an especially critical issue for ornamental crops.

The two-spotted spider mite (Tetranychus urticae) is a tiny arachnid, easily recognized by its oval body shape and the characteristic two large dark spots on either side of its back. Adult females are about 0.5 mm long and more rounded at the rear, while males are smaller, more slender, and noticeably more active. The colour of both males and females can vary widely depending on host plant and environmental conditions—ranging from light green, yellow, and orange to red, brown, or nearly black. For example, mites found on cucumbers often appear yellow-brown, while those on tomatoes tend to be red-brown.

These mites are not insects—they have eight legs, unlike the six-legged insects. Red eyes are visible in all active life stages. Both adults and immature stages prefer the undersides of leaves, where they pierce plant cells and suck out the contents, often forming visible clusters.

Two-spotted spider mites produce fine silk webbing, especially when populations are high. This webbing not only offers them protection but also makes infestations more obvious. Their life cycle—from egg to adult—can be completed in as little as 1–2 weeks under warm conditions, allowing populations to build up rapidly and cause significant damage if not controlled.

Preventing two-spotted spider mites in both production settings and home environments—like backyard vegetable gardens or indoor tropical houseplants—starts with good hygiene and vigilant monitoring. Keep the growing area tidy by removing dead leaves, fallen plant material, and weeds, which can harbor mites and serve as breeding grounds. Whether you're working in a greenhouse or tending to a patio planter, always inspect new plants thoroughly before bringing them into your space. Quarantining new additions for a few days helps prevent introducing mites to healthy plants.

Environmental conditions also play a big role. Spider mites thrive in hot, dry environments, so maintaining adequate humidity—especially indoors—and providing regular, even watering can discourage their development. In home environments, occasional misting or using a humidifier near sensitive plants can help.

Frequent inspection is essential. Check the undersides of leaves where mites prefer to hide, and look for early signs of damage like stippling (tiny yellow dots), leaf curling, or fine webbing. Use a magnifying glass if necessary. Catching an infestation early can make the difference between a manageable issue and a widespread outbreak. For home growers, simply rinsing plants off with a strong stream of water—especially under leaves—can help knock populations down before they get out of hand.

Biological control is one of the most effective and sustainable ways to manage two-spotted spider mites, and beneficial insects offer a natural solution that works in both commercial production and home-growing environments. Among these, Spidex—which contains the predatory mite Phytoseiulus persimilis—is widely considered the most powerful and targeted biocontrol option for active spider mite infestations. Phytoseiulus is a voracious predator that feeds exclusively on all stages of spider mites. It works quickly, particularly in warm, humid environments, making it ideal for greenhouses, tropical plant settings, and high-density crops.

For prevention and early intervention, Spical—which contains Neoseiulus californicus—is a smart choice. This generalist predatory mite is more tolerant of dry conditions and can survive longer in the absence of spider mites by feeding on other small arthropods or pollen. Spical is perfect for use as a preventative treatment in home gardens, houseplants, and commercial settings alike, helping to keep populations in check before a visible outbreak occurs.

In cases of severe infestation, especially when webbing is extensive and multiple generations of spider mites are present, Spidend can be added to the strategy. This product contains Feltiella acarisuga, a gall midge whose larvae actively seek out and consume spider mites, even in dense webbing where predators like Spical may struggle to penetrate. Spidend is especially useful when dealing with hot spots that have grown beyond the control of a single predatory species.

Together, Spidex, Spical, and Spidend form a robust integrated approach for controlling spider mites—from prevention through to curative action—using nature to restore balance in your growing environment.