Invasive Insect: Thrips parvispinus

Native to Southeast Asia, Thrips parvispinus has spread across different continents, including North America. It is suspected that Thrips parvispinus arrived in the United States in Hawaii in the early 2000s. Its presence in the continental USA was confirmed in Florida in 2020 and subsequently in Georgia in 2022/2023. New state records for the USA include Colorado, North and South Carolina. Thrips parvispinus was also identified in Ontario, Canada, in 2021/2022. This rapid expansion highlights the challenges posed by this invasive insect and underscores the need for effective monitoring and management strategies to protect crops and plant species. It is important to note that effective management options against other thrips pests can also efficiently control Thrips parvispinus.

Host plants

Thrips parvispinus can feed on a wide variety of host plants, ranging from ornamental plants to vegetables and fruit crops. They feed on plant tissues by piercing the cells and extracting their contents, causing severe damage, wilting, and, ultimately, yield loss. While the comprehensive list of their hosts in North America is still under assessment, their known host species list includes gardenia, hibiscus, pinwheel jasmine, mandevilla, anthurium, hoya, dahlia, chrysanthemum (mums), ruellia, schefflera, citrus, strawberry, poinsettia, eggplant, peppers, cucumber, beans, zucchini, and more.

Damage

Adults and larvae of Thrips parvispinus feed on leaves and flowers, potentially causing significant damage to plants. Early identification of the damage is important for effective pest management strategies. It has not been reported that Thrips parvispinus transmits any viruses. Common signs and symptoms of infestation include silver scars on foliage, especially in fully developed leaves, distorted or deformed growth, premature leaf drop, scarring on fruits, and the presence of adults and/or larvae. Proper identification is essential, as Thrips parvispinus damage can resemble damage caused by other pests, such as broad mites. To confirm a Thrips parvispinus infestation, gently tap an infested plant over a white sheet of paper to dislodge the thrips, making them easier to observe and helping with identification.

Description

Thrips parvispinus is a very small pest, measuring 1 mm long, making it difficult to spot without magnifying lenses or trained eyes. Adult females are typically dark brown, ranging from brown to black, with light-colored legs and head. Their wings are lighter near the base. In contrast, males are entirely yellow and are about 0.6 mm long. The larval stages closely resemble the adult without wings. The life cycle consists of an egg, two nymphal stages, prepupa, pupa, and adult, completing its life cycle in the span of 13–14 days. Males have a brief lifespan of around six days, while females live for approximately nine days. Females can reproduce without mating and can lay approximately 15 eggs during their lifetime.

Monitoring

Thrips parvispinus has a fast life cycle, making weekly monitoring efforts necessary. Monitoring can be done by gently tapping the plants onto a white sheet of paper. Yellow sticky traps are also a good way to monitor for the presence of Thrips parvispinus. Regular monitoring is essential for early detection and timely intervention in managing this pest.

Management

Managing Thrips parvispinus effectively requires an integrated approach that combines cultural, biological, and chemical control methods. A well-rounded strategy using all three approaches provides the best chance of reducing infestations and minimizing damage.

Cultural Control

Preventing infestations begins with obtaining clean plant material, maintaining good sanitation practices, and promptly removing infested plant material. Regular monitoring is crucial for early detection and intervention.

Biological Control

Biological control can be an effective strategy, particularly when applied preventively or against low infestations. Several natural enemies target different life stages of Thrips parvispinus, offering a sustainable pest management approach. Key options include minute pirate bugs (Orius spp.), brown (Micromus variegatus) and green (Chrysoperla carnea) lacewings at high rates, and the predatory mites Amblydromalus limonicus and crazee mites (Anystis baccarum). Nematodes may help manage the pupal stage in the soil, though further research is needed.

Additionally, the biopesticides BioCeres EC and LaL Guard M52 OD have shown effectiveness in controlling Thrips parvispinus.

Chemical Control

For higher infestations, insecticides labeled for thrips control can be used. However, to minimize the risk of insecticide resistance, it is essential to rotate between different insecticide groups. Always follow label instructions regarding application rates and intervals and ensure proper use of personal protective equipment when handling pesticides.

This list was compiled by Dr. Revynthi, University of Florida.

Reporting Thrips parvispinus

• Contact Dr. Patricia Prade at prade@psu.edu or 717-639-3593.
• Visit a Penn State Extension office close to you.
• Contact the Pennsylvania Department of Agriculture at badbug@pa.gov or 866-253-7189.
• For insect identification, contact Dr. Michael Skvarla at mxs1578@psu.edu or send samples to the Insect Identification Laboratory, Department of Entomology, 501 Agricultural Science & Industries Building, University Park, PA, 16802

References

Ahmed, M.Z., A.M. Revynthi, C.L. McKenzie, and L.S. Osborne. 2023. Thrips parvispinus (Karny), an emerging invasive regulated pest in the United States. Accessed: November 2, 2023

Ataide, L.M., Vargas, G., et al. 2024. Efficacy of Conventional and Biorational Insecticides against the Invasive Pest Thrips parvispinus (Thysanoptera: Thripidae) under Containment Conditions. Insects, 15(1), 48. 

Joseph, S.V. 2023. Watch for Thrips parvispinus in Georgia. Accessed: November 2, 2023

Sugano J, Hamasaki R, Villalobos E, Chou M-Y, Wright M, Fukuda S, Swift S, Ferreira S, Tsuda D, Diaz-Lyke M, Nakamoto S. 2013. Damage to Papaya Caused by Thrips parvispinus (Karny) (poster). Honolulu (HI): University of Hawaii. 1 p.

Summerfield A, and Jandricic S. 2022. Tropical Thrips Species Intercepted on Plant Material in Ontario: Be Aware – But Don't Panic. Accessed: November 2, 2023