Cassava green mite

The Cassava green mite (Latin: Mononychellus tanajoa) is a significant agricultural pest that specifically targets cassava plants. Taxonomically, it belongs to the Kingdom Animalia, Phylum Arthropoda, Class Arachnida, and Family Tetranychidae. While it is classified as a pest rather than a direct pathogen like a fungus, its feeding activity causes systemic damage that mimics severe plant disease symptoms.

The primary symptom of infestation is known as "green mite disease," characterized by chlorosis, leaf deformation, and stunted growth of the apical buds. Heavy infestations lead to extensive defoliation, which severely disrupts the plant's ability to photosynthesize. This inevitably results in a significant reduction in the weight and quality of the harvested cassava tubers, posing a threat to food security.

The biology of Mononychellus tanajoa is characterized by a rapid life cycle, which can be completed in approximately 10 to 14 days under optimal conditions. The mite passes through egg, larva, protonymph, and deutonymph stages before becoming an adult. Because the mite reproduces quickly and survives well in dry, hot conditions, a small initial infestation can rapidly escalate into a major outbreak.

Development and spread are facilitated by warm, dry weather patterns, which are common in many cassava-growing regions. The mite is disseminated largely by wind currents, which carry individuals from plant to plant. Furthermore, human activity plays a role in the long-distance transmission of the pest through the movement of infested stem cuttings used for propagation.

Effective control requires an Integrated Pest Management (IPM) approach. This includes the deployment of resistant cassava varieties and the release of predatory mites, such as Typhlodromalus aripo, which have successfully curbed mite populations in various trials. Chemical control using acaricides is generally discouraged due to the risk of destroying natural predator populations and the risk of pesticide resistance.

• Promoting the use of biocontrol agents to maintain ecological balance.
• Selecting and breeding cassava genotypes resistant to mite feeding.
• Strict quarantine measures for vegetative propagation materials.