Key Pests of Tea and Effective Control Strategies

Tea (Camellia sinensis) is one of the world’s most widely consumed beverages, yet the crop faces constant pressure from a range of pests that can significantly cut into yield and quality. Research from tea-growing regions across Asia shows that pest damage accounts for 10-20% crop loss annually, with certain outbreaks pushing losses far higher. Understanding which pests threaten your plantation – and when they strike – is the first step to protecting it effectively.

The major pests of tea plantations 🔗

As many as 147 insect pests have been recorded on tea, but a handful of them cause the most economic damage. The key leaf pests are mites, thrips, and the tea mosquito bug, while the shot hole borer is the primary stem pest. Caterpillars also cause serious damage, especially during and after pruning cycles.

Mites 🔗

Mites are among the most damaging pests in tea, particularly during hot, dry weather. Two species stand out: the red spider mite and the purple mite.

Tea red spider mite (Oligonychus coffeae) 🔗

The tea red spider mite (Oligonychus coffeae) is scientifically recognized as one of the most serious mite pests of tea globally. This mite thrives in high temperatures and dry conditions, and outbreaks typically coincide with periods of low rainfall. The mite feeds by piercing the upper surface of leaves and extracting chlorophyll, leaving reddish-brown patches that are visible even from a distance. Crop losses from red spider mite infestations range from 17% to 46%. In severe cases, affected leaves dry up and fall off, weakening the entire bush. The mite completes its life cycle in 10-14 days, enabling populations to build rapidly under favourable conditions.

Purple mite 🔗

The purple mite is even smaller than the red spider mite and difficult to spot without magnification. Adults are spindle-shaped with a pinkish-purple colour and feed on the undersides of mature leaves. Damage appears as browning or purpling of leaves, and in heavy infestations, leaf drop can follow. The mite’s entire life cycle takes just one to two weeks, so populations can escalate quickly if left unchecked.

Control of mites 🔗

Managing mites requires a layered approach. Cultural control includes regular field monitoring, proper shade management, and removing alternate host plants such as Bidens and Ageratum that harbour mite populations between seasons. For biological control, phytoseiid mites and coccinellid beetles (ladybird beetles) are natural enemies that can be encouraged in the tea ecosystem. The entomopathogenic fungus Verticillium lecanii applied as a spore suspension is also effective. When chemical intervention is necessary, acaricides such as dicofol, ethion, and fenpropathrin are recommended, applied only after plucking and ensuring thorough coverage of the maintenance foliage. Neem oil is a useful lower-risk option and has been shown to be effective against both red spider mites and purple mites.

Thrips (Scirtothrips bispinosus) 🔗

Thrips are primarily a dry-season pest, with populations building from November onwards and peaking between February and May. They prefer young leaves and buds, and continuous feeding causes lacerations that appear as streaks on the leaf surface, making it uneven and curled. A characteristic sign of thrips damage is the appearance of two parallel lines on the buds where the pest has fed. Both nymphs and adults are destructive, with nymphs causing more harm. They complete their life cycle in 14-20 days, sucking cell sap and leaving a sandpaper-like texture on leaves. Severe infestations cause leaf curling and a burnt-looking appearance that can delay tipping and directly reduce crop yield.

For control, monitoring using yellow sticky traps and maintaining regular shade are the first lines of defence. Natural enemies including anthocorids and predatory thrips can suppress populations. The entomopathogen Verticillium lecanii (now reclassified as Lecanicillium lecanii) has been shown effective against tea thrips. Chemical options include quinalphos, dimethoate, and endosulfan sprays, targeted at shoots on and below the plucking table.

Tea mosquito bug (Helopeltis theivora) 🔗

The tea mosquito bug is one of the most economically damaging pests in tea, particularly active during wet weather conditions when flushes are growing rapidly. Crop losses from this pest can reach 55% in Africa and between 11% and 100% in Asia, depending on the severity of infestation. Adults and nymphs use needle-like mouthparts to pierce leaves, buds, and stems, injecting toxic saliva while sucking out sap. This leaves behind characteristic circular rings around the feeding spots on new flushes, ranging from 0.29 to 2.51 mm in size. The 5th instar nymph is the most voracious feeding stage. Heavily infested fields show widespread necrosis of young shoots, directly reducing the harvested leaf.

Control strategies for the tea mosquito bug combine cultural, biological, and chemical methods. Regular plucking cycles help remove infested shoots before the pest population builds, while pruning eliminates breeding sites. Predatory insects such as praying mantids, lacewings, and spiders feed on this pest. Wettable formulations of the entomopathogenic fungus Beauveria bassiana have been shown to achieve 56-58% control of tea mosquito bugs under field conditions.

Caterpillars 🔗

Several caterpillar species feed on tea foliage, causing defoliation that reduces photosynthetic capacity and weakens plants. They are especially common in fields recovering from pruning.

Flushworm and leaf rollers 🔗

Flushworms and leaf rollers are common in newly pruned tea fields, with populations typically high between August and December. These caterpillars construct leaf nests by webbing leaves together and feed from inside, making them difficult to spot and treat. Their concealed feeding habit means infestations can go unnoticed until significant damage has occurred.

Looper caterpillar (Hyposidra talaca) 🔗

The looper caterpillar is a major defoliator of tea bushes. These caterpillars feed voraciously on tea leaves, leaving cut marks on leaf edges and pinholes. In severe cases, the entire bush can be stripped bare. Female moths lay eggs on shade tree trunks, and after hatching, larvae initially feed on shade trees before migrating to tea bushes. This migration pattern means that shade trees can serve as a reservoir population, so their management is equally important.

For caterpillar control, hand-picking from smaller infestations is practical. Pheromone traps can be used to monitor and control caterpillar populations, while field sanitation – removing leaf litter and pruning debris – reduces shelter and breeding sites. Biological agents including Bacillus thuringiensis (Bt) are widely used against leaf-feeding caterpillars in integrated programmes.

Shot hole borer (Xyleborus fornicatus) 🔗

Unlike the leaf-feeding pests above, the shot hole borer attacks the woody stems of tea plants. The beetle causes two types of injury: primary damage from gallery construction in the stems, which leads to branch breakages, and secondary damage from wood rot that debilitates the plant. The female beetle bores into stems and cultivates a symbiotic ambrosia fungus (Fusarium ambrosium) inside the gallery – it is this fungus, not the wood itself, that both larvae and adults consume. The combination of large beetle numbers and the fungus blocks the plant’s vascular system, preventing the transport of water and nutrients to branches and leaves. The pest is found across most tea-growing regions of Asia, and its concealed habit inside stems makes control particularly challenging.

Chemical control is an integral component of IPM for shot hole borer, but it must be applied prophylactically – spraying after infestation is already established provides limited benefit. Fenthion remains a commonly recommended insecticide for this pest, especially during the pruning season when beetles are most active. Sanitation of infected hosts and preventing the spread of infested material are among the most recommended management strategies. Selecting tea clones with documented resistance to shot hole borer also reduces dependence on repeated chemical treatment.

Integrated pest management (IPM) for tea 🔗

Integrated Pest Management is the cornerstone of sustainable pest control in tea. Rather than relying on a single method, IPM combines monitoring, cultural practices, biological control, and targeted chemical use to keep pest populations below economically damaging thresholds. As CABI emphasises, chemical pesticides should only be used when needed and in a manner that limits exposure of people and the environment to them.

Monitoring and cultural control 🔗

Effective pest management begins with regular field scouting. Sticky traps – yellow for thrips and flying insects, pheromone-baited for specific pests – help track population trends before they reach damaging levels. Cultural practices that reduce pest pressure include timely pruning, removing and destroying infested plant material, maintaining proper shade, and keeping fields clean of debris. Proper plucking cycles are particularly important for controlling the tea mosquito bug, as removing infested shoots directly reduces pest populations.

Biological control 🔗

Tea plantations support a range of natural enemies that, when conserved, can significantly limit pest damage. Predatory mites, ladybird beetles, lacewings, and parasitoid wasps all play a role in suppressing key pests. Microbial agents offer targeted and environmentally friendly control: Beauveria bassiana has demonstrated field efficacy comparable to synthetic chemical pesticides against several tea pests including the tea mosquito bug and shot hole borer, while Lecanicillium lecanii is effective against thrips and spider mites. Neem-based products serve as broad-spectrum botanical controls with minimal environmental impact.

Chemical control as a last resort 🔗

When pest populations exceed threshold levels, chemical control becomes necessary, but product choice and timing matter greatly. Using the wrong pesticide at the wrong time can disrupt natural enemy populations and trigger secondary pest outbreaks – a well-documented problem in tea pest management. Selecting the right pesticide, application method, timing, and dosage is crucial for successful pest control within an IPM strategy. All chemical applications should comply with Maximum Residue Limits (MRLs) stipulated for export markets, and sprays should always be applied after plucking to minimise residue contamination of the harvested leaf.

What do you think? With climate change altering rainfall patterns and dry spells becoming more unpredictable, how do you see the seasonal dynamics of tea pests like mites and the tea mosquito bug shifting in coming years? And do you think biological control agents can realistically replace chemical pesticides as the primary defence in high-pressure tea pest situations?

References

1. https://link.springer.com/chapter/10.1007/978-1-4615-1377-3_11
2. https://eagri.org/eagri50/ENTO331/lecture29/tea/index.html
3. https://www.agrifarming.in/pest-management-in-tea-plantation-major-insect-pest-of-tea-control-and-prevention-methods
4. https://bioprotectionportal.com/resources/tea-pests-identification-damage-and-effective-management/
5. https://www.upasitearesearch.org/pests-diseases/
6. https://www.longdom.org/open-access/tea-pest-management-a-microbiological-approach-84040.html
7. https://academic.oup.com/jipm/article/3/4/A1/922908
8. https://en.wikipedia.org/wiki/Euwallacea_fornicatus