Distribution of Scirtothrips dorsalis (Thysanoptera: Thripidae) cryptic species complex in the United States and reproductive host assessment of its dominant member.

Chilli thrips, Scirtothrips dorsalis Hood, is a cryptic species complex of at least 9 species, 2 of which (South Asia 1 and East Asia 1) have been confirmed damaging >50 plant taxa in the United States. To develop a knowledge-based management program for this pest in the United States, the objectives of the study were to (i) survey for S. dorsalis species complex in the suspected regions and (ii) assess the reproductive hosts of the predominant member available. Thrips samples received from collaborators were subjected to morpholo-molecular characterization. Of the 101 thrips populations received across the United States between 2015 and 2021, 71 populations were confirmed as S. dorsalis, with ~25% further identified as East Asia 1, compared with ~41% identified as South Asia 1, suggesting the latter species is more prevalent in the US. East Asia 1 was primarily found in samples collected from Hydrangea sp. (95%) in Massachusetts, New York, and Pennsylvania, indicating geographic range expansion in the Northeast and successful overwintering in areas with hard freezes. While assessing the host range of South Asia 1 (dominant species), 62 plant taxa were evaluated under greenhouse conditions. Among these, 40 feeding and reproductive hosts were confirmed in Florida. We also found 18 new reproductive hosts and 3 feeding hosts of S. dorsalis, which were not previously reported in the literature. The results provide insight into the increasing host range and expanded geographical distribution of S. dorsalis species and will enable the development of a species-specific monitoring and management program.

Native and Edible Ornamental Plant Congeners Enhance Ecosystem Services Through Key Pest Avoidance and Multifunctionality in Residential Landscapes.

Tea scale, Fiorinia theae Green (Hemiptera: Diaspididae), has long been one of the most important pests of Ilex and Camellia plants, particularly in the southeastern United States. This exotic armored scale insect reduces host plant health and function, and often requires insecticide use, which poses risks to nontarget organisms. While the use of Ilex (Aquifoliales: Aquifoliaceae) and Camellia (Ericales: Theaceae) spp. as landscape ornamentals for aesthetic function is firmly established, we have a poor understanding of species-level susceptibility to F. theae. Additionally, two species, Ilex vomitoria Ait. and Camellia sinensis (L.) O. Kuntze are emerging tisane- and tea-producing commodities in the region, respectively. We propose that these consumable plants may be well-suited alternatives to their traditionally used ornamental congeners in residential landscapes where they may provide enhanced ecosystem services. However, the potential impact of key pests, like F. theae, on these species should be evaluated to anticipate pest pressure that may undermine or offset benefits. In this study, we examine six species within the known host range of tea scale, comparing nonnative I. cornuta Lindl. 'Dwarf Burford,' C. japonica L., C. sasanqua Thunb., and C. sinensis, along with native I. opaca Ait. and I. vomitoria. We found that plant species show a wide range of susceptibility to F. theae and associated damage, with the two native Ilex species and tea-producing C. sinensis displaying the least susceptibility. By reducing the impact of a key pest and considering other ecosystem service traits, these results may help guide more sustainable plant selection decisions where the goal is to integrate native and edible plants into residential landscapes.