Alternative Hosts of Crapemyrtle Bark Scale Mengmeng Gu Associate Professor and Extension Ornamental Horticulturist the Texas A&M University System

Home , Glochidion puberum, Heimia salicifolia, Lagerstroemia

EHT-103 5/18

Alternative Hosts of Crapemyrtle Bark Scale Mengmeng Gu Associate Professor and Extension Ornamental Horticulturist The Texas A&M University System

Crapemyrtle bark scale (Acanthococcus lager- stroemiae) has been confirmed in all the South- eastern U.S. except for Florida. In its native range in East Asia, CMBS is a serious threat to crapemyrtles, persimmons, and pomegranate plants. In the U.S., it is an emerging pest that threatens crapemyrtle production and land- scape use. This is a matter of concern because Fig. 1. A crapemyrtle plant infested crapemyrtle is the highest selling flowering with crapemyrtle bark scale. tree—5 million plants with a combined value of $67M were sold in 2014. Currently, CMBS in the U.S. is only reported Among the documented plants infested by on crapemyrtles, but the spread of CMBS (con- CMBS, other economically important crops firmed by molecular identification) to native include boxwood, soybean, fig, myrtle, cleyera, American beautyberry plants in Texarkana, TX apple, and brambles, such as blackberry, rasp- and Shreveport, LA is alarming. This finding berry, dewberry, juneberry etc. Since Chinese brings to 14 the number of economically and hackberry is identified as a host plant, this raises ecologically important plant families reported concern that the native hackberry—widely as host plants in the CMBS regions of origin established in common crapemyrtle growing (Table 1). regions—may be a possible target species.

Table 1. 1. Buxaceae: Buxus 8. Moraceae: Ficus carica 2. Cannabaceae: Celtis sinensis 9. Myrtaceae: Myrtus 3. Combretaceae: Anogeissus, Anogeissus latifolia 10. Oleaceae: Ligustrum obtusifolium 4. Ebenaceae: Diospyros kaki 11. Pentaphylacaceae: Ternstroemia japonica 5. Euphorbiaceae: Mallotus japonicus 12. Phyllanthaceae: Glochidion puberum 6. Fabaceae: Dalbergia eremicola, Glycine max 13. Rosaceae: Malus pumila, Rubus 7. Lythraceae: Lagerstroemia indica, L. speciosa and Punica granatum 14. Verbenaceae: Callicarpa

1 CMBS may affect the following five beautyberry species (Callicarpa americana, C. formosana, C. ruebella, C. mexicana and C. dichotoma). It may also affect pomegranate, henna, heimia, and winged loosestrife, which has been confirmed under controlled environment. American beautyberry is native in all Southeastern states from Texas to Virginia (Fig. 3), which almost overlap with the CMBS-confirmed states. Natural CMBS infestations of American beautyberry have been found in landscapes in Texas and Louisiana. California produces the most pomegranate, but it is also grown in many states in the south (Fig. 4). Heimia is native in Texas (Fig. 5). Winged loosestrife is native in all states east of Rocky Moun- tains (Fig. 6). These plants, along with many other documented alternative hosts, such as privet, may provide a continuum for spreading CMBS infestation and may cause significant impact on native ecosystems in the Southeast. Although CMBS is rarely kills plants, the Fig. 2. A close-up of the crapemyrtle bark scales and fire ants associated with them. persistent sooty mold it causes on branches and trunks of untreated plants may become unsightly. In extreme cases, the result can be plant romoval Lagerstroemia indica and L. fauriei cultivars from landscapes and a decline in crapemyrtle are the most commonly grown crapemyrtle cul- sales and planting. Crapemyrtles are an import- tivars. In addition to 29 such cultivars, infesta- ant pollen (major protein source for bees) pro- tion of CMBS has been found on 4 crapemyrtle vider during the summer, when flowers from species (Lagerstroemia limii, L. speciosa, L. sub- other plants with pollen are relatively scarce. costata, and L. guilinensis) (Table 2). It’s reason- Crapemyrtle bark scale was listed as a key able to predict that none of these latter common management arthropod and one of the top cultivars or crapemyrtle species are immune to 9 pests reported in the past two years by the CMBS infestation. Greenhouse Grower magazine. In the most recent

Table 2. L. indica and L. fauriei crapemyrtle cultivars Acoma Basham’s Party Pink Biloxi Burgundy Cotton Catawba Chocataw Country Red Diamond Dazzle Ebony and Ivory Ebony Fire Ebony Flame Fantasy Lipan Miami Muskogee Natchez New Orleans Pink Ruffles Pocomoke Powhatan Sarah’s Favorite Royalty Sioux Tuscarora Tuskegee White Twilight Velma William Toovey Yuma Note: Cultivar names in bold indicate that CMBS has been found on the cultivar in both landscapes and the controlled environment. Cultivar names underlined indicate that CMBS has been found on the cultivar in landscapes. The other cultivars were found with CMBS completing life cycle in the controlled environment.

2 Pest Management Strategic Plan for Container California Department of Food and Agriculture and Field-Produced Nursery Crops in FL, GA, has rated CMBS as a 14 on a scale of 1 to15 with KY, NC, SC, TN, and VA: Revision 2015, it was 15 being highest in its pest rating proposal. It noted that “no biological control of the crape- is “likely to establish a widespread distribution myrtle bark scale is known.” However, we have in California;” has “moderate host range,” has found that several lady beetle species and green “both high reproduction and dispersal poten- lacewing larvae prey on CMBS. There is no tial;” and “could cause both economic and report of CMBS in California currently, but the environmental impacts.”1

Fig. 3. Callicarpa americana distribution map Fig. 5. Hemia salicifolia distribution map https:// https://plants.usda.gov/core/profile?symbol=caam2. plants.usda.gov/core/profile?symbol=HESA.

Fig. 4. Punica granatum distribution map https:// Fig. 6. Lythrum alatum distribution map https:// plants.usda.gov/core/profile?symbol=PUGR2. plants.usda.gov/core/profile?symbol=LYAL4.

3 Many exotic pests that appear benign, not too harmful, or even useful at first glance are becoming invasive and causing significant economic and environmental impacts—CMBS should be taken very seriously. For life cycle and management of CMBS, please see Texas A&M AgriLife Extension Service publication EHT-049: Crape Myrtle Bark Scale: A New Exotic Pest available at www. agrilifebookstore.org.

Mentioned species common and scientific names American beautyberry – Callicarpa americana Apple – M. pumila Boxwood – Buxus Brambles, such as blackberry, raspberry, dewberry, juneberry etc. – Rubus Chinese hackberry – C. sinensis Cleyera – T. japonica Crapemyrtle – Lagerstroemia spp. Fig – F. carica Henna – Lawsonia inermis Heimia – Heimia salicifolia Myrtle – Myrtus Native hackberry – C. occidentalis Persimmon – Diospyros kaki Pomegranate – Punica granatum Privet – Ligustrum spp. Soybean – G. max Winged loosestrife – Lythrum alatum

1. (http://blogs.cdfa.ca.gov/Section3162 /?tag=crapemyrtle-scale)

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