Crapemyrtle bark scale (CMBS, Acanthococcus lagerstroemiae), an invasive polyphagous sap-sucking hemipteran, has spread across 14 states of the United States since 2004. The infestation of CMBS has negatively impacted the flowering of ornamental plants and even the fruiting of some crops. Host identification is critical for determining potential risks in ecosystems and industries and helps develop strategic management. A host confirmation test was performed over 25 weeks using six Lagerstroemia species (L. caudata, L. fauriei ‘Kiowa’, L. indica ‘Dynamite’, L. limii, L. speciosa, and L. subcostata) and California loosestrife (Lythrum californicum). The 25-week observations confirmed all tested plants as the hosts. The repeated measures of analysis of variance (ANOVA; Tukey’s HSD, α = 0.05) indicated that the average number of CMBS females differed significantly between L. limii and L. speciosa. The highest number of the females observed on L. limii was 576 ± 25 (mean ± SE) at 17 weeks after inoculation (WAI), while the highest number was 57 ± 15 on L. speciosa at 19 WAI. In addition, L. subcostata and L. speciosa had significantly high and low numbers of males, respectively, among the Lagerstroemia species. Our results suggest that L. speciosa could be incorporated in developing new cultivars with low CMBS suitability.

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae) is an exotic pest species that causes aesthetic and economic damage to crapemyrtles and poses potential threats to other horticultural crops in the United States. Although previous studies reported the infestation of CMBS on several alternative hosts across multiple families in Asia, its potential threats to other documented alternative hosts remain elusive and yet to be confirmed. In this study, feeding preference studies of CMBS were conducted on forty-nine plant species and cultivars in 2016 and 2019, in order to gain insight into the expansion of CMBS distribution in the United States, as well as other regions of the world. The infestations of CMBS were confirmed on apple (Malus domestica), Chaenomeles speciosa, Disopyros rhombifolia, Heimia salicifolia, Lagerstroemia ‘Spiced Plum’, M. angustifolia, and twelve out of thirty-five pomegranate cultivars. However, the levels of CMBS infestation on these test plant hosts in this study is very low compared to Lagerstroemia, and may not cause significant damage. No sign of CMBS infestation was observed on Rubus ‘Arapaho’, R. ‘Navaho’, R. idaeus ‘Dorman Red’, R. fruticosus, B. microphylla var. koreana × B. sempervirens, B. harlandii, or D. virginiana.

Crapemyrtle bark scale [CMBS (Acanthococcus lagerstroemiae)], a newly emerged pest in the United States, has spread to 16 U.S. states and unexpectedly spread on a native species american beautyberry (Callicarpa americana) in Texas and Louisiana in 2016 since it was initially reported on crapemyrtles (Lagerstroemia sp.) in Texas in 2004. The infestation of CMBS negatively impacted the flowering of crapemyrtles. We observed the infestation on the two most commercially available edible fig (Ficus carica) cultivars Beer’s Black and Chicago Hardy in a preliminary trial in 2018. To help estimate CMBS potential in aggravating risks to the ecosystem stability and the green industry, we conducted a host range and suitability test using ‘Bok Tower’ american beautyberry as a positive control with other eight beautyberry (Callicarpa) species [mexican beautyberry (C. acuminata), ‘Profusion’ bodinieri beautyberry (C. bodinieri), ‘Issai’ purple beautyberry (C. dichotoma), japanese beautyberry (C. japonica var. luxurians), ‘Alba’ white-fruited asian beautyberry (C. longissima), taiwan beautyberry (C. pilosissima), luanta beautyberry (C. randaiensis), and willow-leaf beautyberry (C. salicifolia)] and three fig (Ficus) species [creeping fig (F. pumila), roxburgh fig (F. auriculata), and waipahu fig (F. tikoua)] over 25 weeks. All the tested beautyberry species and waipahu fig sustainably supported the development and reproduction of nymphal CMBS and were confirmed as CMBS hosts. Furthermore, comparing with the control, mexican beautyberry, ‘Profusion’ bodinieri beautyberry, taiwan beautyberry, and willow-leaf beautyberry were significantly less suitable, while ‘Issai’ purple beautyberry, japanese beautyberry, ‘Alba’ white-fruited asian beautyberry, and luanta beautyberry were as suitable as ‘Bok Tower’ american beautyberry. Thus, when using beautyberries in landscapes, their different potential to host CMBS should be considered to minimize spreading CMBS through the native ecosystems.

Crapemyrtle Bark Scale (Acanthococcus lagerstroemiae; CMBS) is an invasive pest species that primarily infest crapemyrtles (Lagerstroemia spp.) in the United States. Recent reports have revealed the dire threat of CMBS to attack not only crapemrytles but also the U.S. native species with expanded host plants such as American beautyberry (Callicarpa spp.) and Hypericum kalmianum L. (St. Johnswort). A better understanding of plant–insect interaction will provide better and environmental-friendly pest management strategies. In this study, we constructed the first comprehensive life table for CMBS to characterize its biological parameters, including developmental stages, reproductive behavior, and fecundity. The indirect effects of three plant nutrient conditions (water, 0.01MS, and 0.1MS) on CMBS populations were examined using the age-stage, two-sex life table. The demographic analyses revealed that the plant nutrient conditions had significantly altered CMBS development in terms of the intrinsic rate of increase (r), the finite rate of increase (λ), the net reproductive rate (R0), and mean generation time (T). Higher r, λ, and R0 were recorded under nutrient-deficient conditions (water), while CMBS reared on plants with healthier growing conditions (0.1MS) had the most prolonged T. Overall, CMBS shows better insect performance when reared on plants under nutrient-deficient conditions.

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana) is an invasive insect that was first discovered in the United States in 2004. The polyphagous feeding habit of CMBS has allowed it to infest a wide range of plant species beyond its primary host, Lagerstroemia. Using molecular approaches, we studied the genetic relationships between CMBS specimens and their hosts from different geographic locations. Naturally occurring CMBS infestations were confirmed on American beautyberry (Callicarpa americana L.), a native plant species in the United States, and spirea (Spiraea L.). The new infestation of CMBS found on Spiraea raises the alarm that other economically important crops in the Amygdaloideae subfamily (subfamily under Rosaceae) might be susceptible to CMBS attacks.

Host range confirmation of invasive hemipterans relies on the evaluation of plant susceptibility though greenhouse or field trials, which are inefficient and time-consuming. When the green industry faces the fast-spreading threat of invasive pests such as crapemyrtle bark scale (Acanthococcus lagerstroemiae), it is imperative to timely identify potential host plants and evaluate plant resistance/susceptibility to pest infestation. In this study, we developed an alternative technology to complement the conventional host confirmation methods. We used electrical penetration graph (EPG) based technology to monitor the A. lagerstroemiae stylet-tip position when it was probing in different plant tissues in real-time. The frequency and relative amplitude of insect EPG waveforms were extracted by an R programming-based software written to generate eleven EPG parameters for comparative analysis between plant species. The results demonstrated that the occurrences of phloem phase and xylem phase offered conclusive evidence for host plant evaluation. Furthermore, parameters including the percentage of insects capable of accessing phloem tissue, time duration spent on initiating phloem phase and ingesting phloem sap, provided insight into why host plant susceptibility differs among similar plant species. In summary, this study developed a novel real-time diagnostic tool for quick A. lagerstroemiae host confirmation, which laid the essential foundation for effective pest management.

Host range confirmation of invasive hemipterans relies on the evaluation of plant susceptibility though greenhouse or field trials, which are inefficient and time-consuming. When the green industry faces the fast-spreading threat of invasive pests such as crapemyrtle bark scale (Acanthococcus lagerstroemiae), it is imperative to timely identify potential host plants and evaluate plant resistance/susceptibility to pest infestation. In this study, we developed an alternative technology to complement the conventional host confirmation methods. We used electrical penetration graph (EPG) based technology to monitor the A. lagerstroemiae stylet-tip position when it was feeding on different plant tissues in real-time. The frequency and relative amplitude of insect feeding waveforms (recorded by EPG) were extracted by an R programming-based software written to generate eleven feeding parameters for comparative analysis between plant species. The results demonstrated that the occurrences of phloem phase and xylem phase offered conclusive evidence for host plant evaluation. Furthermore, parameters including the percentage of insects capable of accessing phloem tissue, time duration spent on initiating phloem phase and ingesting phloem sap, provided insight into why host plant susceptibility differs among similar plant species. In summary, this study developed a novel real-time diagnostic tool for quick A. lagerstroemiae host confirmation, which laid the essential foundation for effective pest management.Simple SummaryCrapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae), an invasive polyphagous sap feeder in the United States, has spread across 16 U.S. states in less than two decades, posing potential risks to the Green Industry. Confirming the host range is crucial for effective pest management of invasive insects. However, host range confirmation relying on greenhouse or field trials is often inefficient and time-consuming. In this study, we used the electrical penetration graph (EPG) to monitor the stylet penetration of CMBS in plant tissue in real-time. An R programming-based application was developed to better characterize the insect feeding waveforms recorded by EPG. By analyzing EPG-based feeding parameters, we demonstrated that CMBS have difficulty accessing the phloem tissue (salivation and ingestion) of a resistant plant compared to a susceptible plant. Importantly, we hereby present CMBS typical feeding behaviors on susceptible and non-susceptible plants comparatively, which provides direct evidence for revealing unknown hosts rapidly.

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana), a fast-spreading invasive insect, has been causing damage to popular landscape plants in at least 17 states in the United States since 2004. This invasive insect has a list of documented plant hosts in ∼23 genera, which includes its primary hosts, crapemyrtles (Lagerstroemia spp.), as well as other important plant species, such as pomegranates, apple, and the native plant American beautyberry. Previous studies have shown CMBS causes different levels of feeding damage among its plant hosts, while the underlining plant defense mechanisms toward CMBS attacks remain elusive. A better understanding of plant–CMBS interactions and how CMBS performs under different plants (e.g., a susceptible vs. a resistant host) can provide valuable guidance for integrated pest management. Therefore, in this study, we conducted the age-stage, two-sex table study analysis to evaluate the biological parameters of CMBS on different species or cultivars of crapemyrtle under laboratory conditions (25 °C and 250 μmol·m−2·s−1 light with a photoperiod of 12 hours:12 hours (light:dark). Crapemyrtle bark scale development was found to be greatly influenced by the hosts. This study aims to provide important biological and ecological data on CMBS using a comprehensive life table study to gain a thorough understanding of its development, survival, and fecundity on different crapemyrtle species or cultivars.