What is Tomato Russet Mite?
The tomato russet mite is one of the smallest arthropods, measuring less than 0.2 millimeters in length. Belonging to the Eriophyoidea superfamily, it is a specialized pest that primarily targets tomato plants (Solanum lycopersicum), although it can also survive on other solanaceous plants such as potatoes, tobacco, and peppers. Its tiny size makes it difficult to detect without magnification, often allowing infestations to go unnoticed until significant damage has occurred.
The Biology of Aculops lycopersici
Tomato russet mites are uniquely adapted to their environment. Unlike most arachnids, they possess only two pairs of legs instead of the usual four. Their needle-like mouthparts allow them to pierce the epidermal cells of plants, siphoning off the cell contents. This feeding activity causes a rapid collapse of leaf hairs, leading to the withering, bronzing, and eventual necrosis of leaves and stems. The damage inflicted by Aculops lycopersici can superficially resemble a microbial disease, making it challenging to diagnose without proper magnification and experience.
Life Cycle and Biology
The life cycle of tomato russet mites is relatively short, with the potential for rapid population growth under favorable conditions. Female mites can lay up to four eggs per day, and under optimal conditions, the mite's life cycle—from egg to adult—can be completed in as little as five days. The mites are haplodiploid, meaning that unfertilized eggs develop into males while fertilized eggs develop into females. This reproductive strategy allows for quick adaptation and expansion, particularly in environments like greenhouses where conditions are stable and warm.
Impact on Tomato Plants
Tomato russet mite actively manipulates its host plant's defense mechanisms. The mite suppresses the jasmonic acid (JA) signaling pathway in tomatoes, a crucial pathway responsible for the production of defensive metabolites against herbivores. By disrupting this pathway, russet mites renders the tomato plant defenseless, allowing the mite populations to multiply rapidly and cause extensive damage.
Controlling Tomato Russet Mites
Given the mite's ability to suppress plant defenses and its tiny size, early detection and control are critical. Regular monitoring of tomato plants, especially under the leaves and along the stems, is essential. Integrated pest management strategies, including the introduction of predatory mites like SwiLiv (Amblyseius swirskii) and BarkeLiv ( Neoseiulus barkeri) can help. However, the mite’s rapid reproduction and ability to go unnoticed due to its tiny size make it a challenging pest to manage.
Images sourced:
Greenhalgh, R., Dermauw, W., Glas, J. J., et al. (2020). Genome streamlining in a minute herbivore that manipulates its host plant. eLife, 9, Article e56689.