https://orcid.org/0000-0002-3283-1306
Abstract
Tuta absoluta (Meyrick) has emerged as a significant pest of solanaceous crops, particularly tomatoes. Although its host range includes other plants within the Solanaceae family, this manuscript presents the first evidence of T. absoluta infesting and causing damage to Solanum indicum (Indian nightshade). Observations were conducted under greenhouse conditions, where pest-induced foliar damage caused by larval feeding was documented. These findings expand the known host range of T. absoluta, highlighting the potential risks of additional solanaceous crops and informing future pest management strategies.
Solanum indicum, commonly known as Indian nightshade, is a species within the diverse Solanaceae family that has received limited attention. This family includes several important agricultural crops, including tomato (Solanum lycopersicum), potato (Solanum tuberosum), and eggplant (Brinjal) (Solanum melongena) (Aubriot and Daunay 2019, Fiesel et al. 2022, Talucder et al. 2024). Unlike its more widely recognized relatives, S. indicum possesses unique cultural and medicinal significance, particularly in traditional medicine across various regions of Asia and Africa (Amoo et al. 2017). This perennial shrub is distinguished by its striking purple flowers and small, spherical fruits that transition from green to yellow as they ripen. Various parts of the plant, including the roots, leaves, and fruits, have been used in indigenous medicinal systems for their purported therapeutic properties (Amoo et al. 2017).
Historically, S. indicum has been used to treat a various ailments, including respiratory conditions, fever, and digestive issues (Yadav and Tiwari 2024). The plant’s bioactive compounds, such as alkaloids and flavonoids, contribute to its pharmacological activities, including anti-inflammatory, antioxidant, and antimicrobial effects (Jan et al. 2024). Despite these traditional applications, scientific research on S. indicum remains relatively limited compared to that on other solanaceous crops. Its status as a lesser-known species often leads to its being overlooked in broader agricultural and pest management studies. Recognizing S. indicum as a host for pests like T. absoluta can have significant implications for local farming practices, particularly in regions where the plant is cultivated for medicinal or subsistence purposes. Understanding the pest–host interactions involving S. indicum is crucial for developing comprehensive pest management strategies that protect this valuable yet underappreciated plant species.
Historically, Tuta absoluta (Meyrick) has attracted significant attention because of its severe impact on tomato (S. lycopersicum) (Vivekanandhan et al. 2024a, b). Native to South America, this invasive pest has spread globally, infesting regions in Europe, Asia, and Africa (Desneux et al. 2011, Campos et al. 2017, Biondi et al. 2018). Its rapid proliferation and high reproductive rate pose a formidable challenge for tomato producers. The tomato is the primary target of T. absoluta because of its nutritional profile and structure, which provide ideal conditions for larval development (Desneux et al. 2011). Additionally, potato (S. tuberosum) and eggplant (S. melongena) have been identified as secondary hosts, although reports of severe infestations in these crops are less frequent (Chen et al. 2021, Mahlangu et al. 2022).
Recent observations have highlighted the adaptability of pest and its ability to expand its host range to other members of the Solanaceae family. This flexibility in host selection poses an increasing threat to a broader spectrum of solanaceous plants, including both wild and cultivated species of economic and ecological significance. The ability of T. absoluta to infest and damage plants beyond tomato presents a critical challenge for integrated pest management (IPM) programs, which must evolve to anticipate and mitigate the risks to non-traditional hosts. The expansion of T. absoluta to new host plants suggests that crops previously considered safe from significant infestations may now be at risk. This is particularly concerning for regions with diversified agriculture that include multiple solanaceous species, as an expanded host range could disrupt ecosystems and threaten food security. Proactive monitoring, research, and adaptive management strategies are essential to address this evolving threat and protect a wider range of crops from the destructive potential of T. absoluta.
In this paper, we report the first recorded evidence of T. absoluta infesting S. indicum, providing valuable insights into the pest’s expanding host range. This highlights the adaptability of pests and may indicate new vulnerabilities within agricultural ecosystems. The confirmation of S. indicum as a host could have significant implications for both agricultural and ecological pest management strategies, particularly in regions where this plant is cultivated for medicinal or subsistence purposes. Understanding this new host-pest relationship is crucial for updating monitoring practices, enhancing IPM approaches, and ensuring the protection of diverse solanaceous crops from potential damage.
Plant Selection
A greenhouse with screen walls typically maintains a temperature range of 20 to 30 °C (68 to 86°F) and humidity levels of 60% to 80%. Unlike a fully enclosed greenhouse, itis a semi-protected growing environment with openings to the exterior surroundings, allowing for some interaction with the outside climate. We first observed T. absoluta feeding on S. indicum in a semi-greenhouse located in Chiang Mai, Thailand (Latitude: 18.7903° N; Longitude: 98.9873° E). Several solanaceous species were grown in green house environment, including Solanum lycopersicum (tomato), Solanum indicum (Indian nightshade), Nicotiana tabacum (tobacco), and Solanum tuberosum (potato), for experimental purposes. Regular inspections were conducted to assess foliar damage, larval feeding, and characteristic damage patterns associated with T. absoluta infestations. Symptoms of T. absoluta include irregular mining patterns on leaves, which appear as pale, white streaks or tunnels. Severe infestations can lead to leaf deformation, yellowing, drying, and fruit drop or rot.
Pest Identification
The infestation of T. absoluta on S. indicum plants was assessed using a combination of methods. Initial visual inspections were conducted to identify characteristic signs of damage, such as leaf mining and webbing (Figs 1 and 2). Larvae found on the affected plants were carefully collected and reared under controlled conditions until they matured into adult moths. Adult moths were then examined and identified based on their distinct morphological features, including wing patterns and size, which were compared with the established descriptions of T. absoluta (Vivekanandhan et al. 2024a). Both larvae and adults were captured and identified as T. absoluta by comparing them with specimens from Yunnan University, China, and using 5.8S ribosomal RNA gene sequencing techniques.
A-C demonstrated that T. absoluta causes significant damage to the leaves of S. indicum. (A) early leaf mining, (B) leaf mining with obvious frass, and (C) a clearly developed larva.
The morphological characteristics of S. indicum, including its eggs, larvae, pupae, and adults, were identified based on the specific traits associated with T. absoluta.
Morphological Confirmation
The species identity was confirmed morphologically using identification keys (ITP Identification Technology Program https://idtools.org/microlep_solan/index.cfm?packageID=1101&entityID=2869). Comparison of the male genitalia, including the shape of the valve, vinculum, and other reproductive structures, provided a clear match with T. absoluta.
Molecular Level Confirmation
Our previous molecular sequence analysis revealed that the collected insect pest was T. absoluta and its DNA sequence consisted of 784 base pairs. To identify matching sequences, we conducted a search using the Basic Local Alignment Search Tool (BLASTN). Our T. absoluta sequence (PP843570) and the corresponding phylogenetic tree were found to be 100% identical to previously published T. absoluta sequences, including GU353340.1, HQ879987.1, HQ879972.1, HQ879990.1, HQ879991.1, and HQ879993.1.
Discussion
This study presents a novel report identifying Solanum indicum (S. indicum) as a new host for Tuta absoluta (T. absoluta). Our findings, based on both morphological and molecular evidence, confirmed that T. absoluta infests S. indicum and causes significant damage, similar to its effects on tomatoes (Fig. 1). The larvae feed on the foliage, stems, and fruits of S. indicum, resulting in symptoms, such as leaf mining, defoliation, and reduced plant vigor (Fig. 1). Similar to the present study, T. absoluta larvae feed on the foliage, stems, and fruits of tomato (S. lycopersicum L.), resulting in symptoms such as leaf mining in most leaves, as well as damage to the fruits and stems (Mohamed et al. 2015, Vallad et al. 2018, Buragohain et al. 2021).
Morphologically, the moths infesting S. indicum plants exhibited features closely resembling those of T. absoluta (Figs 1 and 2). The appressed scales on the head and the scaly labial palps matched the characteristics of T. absoluta, and the male genitalia were also identical to those of T. absoluta (Fig. 2). Molecular analysis, conducted previously through sequencing and comparison using BLASTN, confirmed that our sequence (PP843570) was 100% identical to other published T. absoluta sequences, thereby supporting the species identification, and similar to the present study Tabuloc et al. (2019) reported that similar nucleotide base pairs was reported in T. absoluta tomato insect pest.
Conclusion
This report marks the first documented case of T. absoluta infesting S. indicum, thus expanding the known range of hosts for this destructive pest. The discovery emphasizes the pest’s capacity to adapt and exploit new plants within the Solanaceae family, which could have far-reaching consequences for agricultural practices. These findings call for increased vigilance among farmers and researchers, as S. indicum has not traditionally been a focus of pest management programs. The emergence of this new host suggests that current pest control measures may need significant updates to include monitoring and protective strategies for a broader spectrum of solanaceous crops. Adjustments to IPM protocols may be necessary to prevent potential infestations and damage in regions where S. indicum and other under-monitored solanaceous plants are cultivated. This proactive approach would help safeguard crop diversity and maintain sustainable agriculture, ensuring that pest control practices remain effective against the evolving threats posed by adaptable pests like T. absoluta.
Acknowledgments
The author (Perumal Vivekanandhan) would like to express their gratitude to the Office of Research Administration and the Department of Entomology and Plant Pathology at Chiang Mai University, Thailand, for their help in providing laboratory resources and financial support. The authors also extend their thanks to the Yunnan Province Science and Technology Department for the “Yunnan International Joint Laboratory of Fruit-Vegetable-Flower Invasive Insect Pest Management (Yunnan FVF-IPM Joint Lab)” (No. 202303AP140018). Also this research was partially supported by Chiang Mai University and the Center of Excellence on Agricultural Biotechnology, Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation (AG-BIO/MHESI). We would like to thank the Department of Agricultural Animal Science at the Faculty of Agriculture, Chiang Mai University, for their ethical approval of this study (Animal Welfare Number: AG04001/2567). This approval ensures that all research involving insects was conducted in compliance with relevant animal welfare regulations and ethical guidelines.
Author contributions
Perumal Vivekanandhan (Conceptualization [lead], Data curation [lead], Formal analysis [lead], Investigation [lead], Methodology [lead], Project administration [lead], Resources [lead], Software [lead], Supervision [lead], Validation [lead], Visualization [lead], Writing—original draft [lead], Writing—review & editing [lead]), Kannan Swathy (Conceptualization [equal], Data curation [equal], Formal analysis [equal], Methodology [equal], Resources [equal], Software [equal], Validation [equal], Visualization [equal], Writing—original draft [equal], Writing—review & editing [equal]), Thanandon Siripan (Data curation [supporting], Formal analysis [supporting], Resources [supporting], Writing—original draft [supporting], Writing—review & editing [supporting]), Sarayut Pittarate (Validation [supporting], Visualization [supporting], Writing—original draft [supporting], Writing—review & editing [supporting]), and Patcharin Krutmuang (Conceptualization [supporting], Funding acquisition [lead], Investigation [supporting], Project administration [equal], Resources [equal], Writing—original draft [supporting], Writing—review & editing [equal])
Conflicts of interest. The authors declare that they have no conflict of interest.
