Tuta absoluta
Tomato leaf miner
Tuta absoluta is a small brown moth whose larvae aggressively attack tomato plants by mining into leaves, stems, and fruits. . If uncontrolled, infestation can cause yield losses ranging from 11% to 100% in the worst cases (CABI, 2019).
Photo credit: Elha Wulansari
Fig. 1. Tomato plant leaf damaged by a leaf miner insect (the leaf shows distinctive white trails and a small larva)
Introduction
Tuta absoluta (or Phthorimaea absoluta), belonging to the family Gelechiidae, was first identified in Peru in 1917. Since then, the pest has spread rapidly across Europe, Africa, and Asia, and is now on the doorstep of Southeast Asia (Vivekanandhan, 2024; World Vegetable Center, 2023).
The economic impact of T. absoluta is already evident worldwide. For example, in the Netherlands alone, estimated losses caused by infestations reach €5–25 million (World Vegetable Center, 2023). Turkey spends around $183.7 million each year on control measures (Oztemiz, 2014), while Nepal reported crop losses amounting to $19.7 million in just the first year of invasion (Bajracharya et al., 2016).
Given these global experiences, it is crucial to understand what is at stake for Southeast Asia. This page discusses why Tuta absoluta causes a serious threat to the region, the initiatives already implemented to manage it, and the policies and regulations designed to prevent its further spread.
Life Cycle & Symptoms
Tuta absoluta is a small Lepidopteran moth with a high reproductive potential, and although its biological cycle depends on temperature, it is capable of over 10 generations per year under optimal conditions (NAPPO, 2013). The life cycle of Tuta absoluta consist of four stages, started from egg, larvae, pupae, and adult.
Egg Stage
Appearance:
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Eggs are small.
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Cylindrical.
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Creamy white to yellow-orange.
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Size: 0.35 mm long.
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Lay up to 260 eggs.
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Hatching: Occurs in 4-6 days, depending on temperature.
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Location: Aerial parts of host plants, on the underside of leaves or stems and to a lesser extent on fruits.
Fig. 2: Tuta absoluta egg which is a yellow colour. Photo ©CABI.
Larval (Caterpillars) stage - Most damaging stage
Appearance:
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Cream coloured with a characteristic dark head and a lateral spot that extends from the ocellus to the posterior margin.
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Develop through four larval stages (Instar).
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Turn green to light pink (2nd–4th instar)
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Size: 1 and 8 mm at the final instar.
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Completed within 12-15 days under optimal conditions.
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Location: Plant tissue (leaves, aerial fruits or stems).
Fig. 3: A Tuta absoluta larva showing the green and pink as it develops. Photo ©CABI.
Pupal stage
Appearance:
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Greenish when just formed, becoming darker in colour as they near adult emergence.
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Cylindrical in shape.
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Often coated with a white silky cocoon.
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Location: Pupae have been found in the mines, outside the mines, in the soil, and leaves or in the calyx.
Fig. 4: The Tuta absoluta pupae. 1) male. 2) female.
Photo ©M.A. Uchoa-Fernandes.
Adult stage
Appearance:
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Size: 5-7 mm long with a wingspan of 8-10 mm.
Important for identification:
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Filiform antenna.
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Grey coloured scales.
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Black spots present on the anterior wings.
Fig. 5: Tuta absoluta moth with the distinctive brown and grey patterned wings and antenna with alternate light and dark sections.
Photo ©CABI.
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Symptoms
Fig. 6: [Exit holes] one of the main signs of a Tuta absoluta infestation.
Photo ©CABI
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Evidence of boring or internal feeding across the whole plant, including on the fruit, growing points, flowers, leaves and stems.
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The fruit is an abnormal shape and/or reduced in size.
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Obvious exit holes on the fruit.
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The fruit drops, and the flowers fall or shed prematurely.
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Evidence of external feeding on the flowers and leaves.
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Leaves grow in abnormal forms or shapes or remain folded or rolled.
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The whole plant dies back.
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Confusion with Other Pests
These insects may have similar symptoms on tomato plants:
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Liriomyza spp. (Leaf miner flies). Damage: Creates irregular serpentine mines on tomato leaves
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Helicoverpa armigera (Tomato fruit borer / Cotton bollworm). Damage: Feeds on fruits, flowers, and leaves, causing holes in tomato fruits
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Keiferia lycopersicella (Tomato pinworm). Damage: Mines leaves, stems, and fruits of tomato; symptoms closely resemble Tuta absoluta
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Bemisia tabaci (Whiteflies). Damage: Cause yellowing and curling of leaves; transmit tomato viruses; sometimes confused with miner stress.
Spread and Current Status in Southeast Asia
According to the World Vegetable Center, Tuta absoluta has not yet been widely reported in most Southeast Asian countries, but the threat is imminent. Predictive modeling (FAO, 2019) shows T. absoluta could invade all major vegetable-growing areas of mainland Southeast Asia within 5–7 years if unchecked.
Research confirmed the first occurrence of Tuta absoluta in Myanmar.
Myanmar has reported the occurance of Tuta absoluta through the preliminary surveys on on tomato crops in Southern Shan State (the largest tomato production area in Myanmar), but there was no official survey conducted until the end of 2019. Therefore, the study was conducted by Yule at al. (2021) to confirm the presence of T. absoluta in Myanmar. Their key findings include:
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Tuta absoluta presence was confirmed in all fields and locations surveyed in Myanmar.
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The amount of T. absoluta larvae was significantly higher in the lower third of the plants.
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The author pointed out the importance of plant protection and quarantine offices of ASEAN member states coordinate their response to T. absoluta and build their capacity to monitor the pest and develop a strategy for when it arrives.
Reference:
Yule, S., Htain, N. N., Oo, A. K., Sotelo-Cardona, P., & Srinivasan, R. (2021). Occurrence of the South American Tomato Leaf Miner, Tuta absoluta (Meyrick) in Southern Shan, Myanmar. Insects, 12(11), 962. https://doi.org/10.3390/insects12110962 [LINK]
Pest status of Tuta absoluta in Thailand
The Department of Agriculture (DOA), as the NPPO of Thailand, has received a report confirming the presence of the tomato leaf miner (Tuta absoluta) from samples collected from tomato orchards in Chiang Mai Province in March 2019.
Important findings from the survey included:
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Tuta absoluta was detected in tomato and potato orchards in only 8 provinces (Mae Hong Son, Chiang Mai, Tak, Loei, Nong Khai, Bueng Kan, Nakhon Phanom and Phetchabun).
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The DOA has established control programs for T. absoluta that combine different approaches including Integrated pest management strategy includes the use of both chemical and biological insecticides.
More information on the Tuta absoluta policies and current control status in the region
Innitiave for controling Tuta absoluta in the region
Regional cooperation is already underway. In 2022–2023, a Japan-funded initiative led by WorldVeg provided training for quarantine officers across all ten ASEAN member states on how to identify, monitor, and respond to Tuta absoluta outbreaks. In December 2022, WorldVeg brought together 27 quarantine officers from Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam for hands-on sessions. Below are the key outcomes of this initiative:
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Participants gained knowledge on the importance of proper phytosanitary procedures, including inspection, monitoring, and both morphological and molecular identification of Tuta absoluta at all life stages, as well as the main pathways of invasion
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Participants learned the management strategies when the pest arrives.
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WorldVeg experts worked with participants to develop ten country-specific risk assessments and surveillance protocols, tailoring them to each nation’s needs and the data gathered during the training
Reference:
World Vegetable Center. 2024. Annual Report 2023. Publication 24-1081. World Vegetable Center, Shanhua, Taiwan. 112pp [LINK]
Key Management Strategies
The Insecticide Resistance Action Committee (IRAC) has outlined key management tactics for Tuta absoluta, focusing on sustainable approaches to reduce crop losses and delay resistance development.
Source: Insecticide Resistance Action Committee (IRAC), July 2021
Several Selected Key Management Tactics
More information click the [LINK]
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Use pest-free transplants.
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Monitor pest using delta pheromone indicator traps.
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Disrupt mating using industry approved/recommended pheromone dispensers.
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Between planting cycles, cultivate the soil and cover with plastic mulch or perform solarisation in greenhouses.
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Allow a minimum of 6 weeks from crop destruction to next crop planting.
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Inspect the crop regularly to detect the first signs of damage.
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Constantly, remove and destroy attacked plant parts.
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Establish populations of effective biological control agents (e.g.Nesidiocoris).
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Select insecticides based on known local effectiveness and selectivity.
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Rotate insecticides by MoA group using a “windows” approach.
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Use only insecticides registered for control of T. absoluta.
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Always follow the directions for use on the label of each product.
Biological control
Biological agents offer sustainable alternatives or supplements to chemicals which develops resistance to the pests. Many natural enemies of T. absoluta have been identified such as predators Nesidiocoris tenuis and Macrolophus spp., lacewings (Chrysoperla carnea), and generalist predators (ants, spiders).
Resourches