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Bean Plataspid: Megacopta cribraria (Fabricius) (Insecta: Hemiptera: Heteroptera: Plataspidae)1

Ashley Poplin and Amanda Hodges2

Introduction

The bean plataspid, Megacopta cribraria (Fabricius), also known as the kudzu bug, lablab bug, and globular stink bug, is native to Asia. The bean plataspid was first reported in the United States in October 2009 (Eger et al. 2010). Before its detection, species of the family Plataspidae were not known to be in the Western Hemisphere. Aggregations were first detected on the outside of houses and surrounding vegetation in Georgia. Currently, the distribution of the bean plataspid in the U.S. includes six southeastern states.

DNA data confirmed that the introduction of the bean plataspid to the United States occurred from a single female lineage originating in Japan (Jenkins and Eaton 2011). DNA from two endosymbionts (organisms that live within another organism) found in bean plataspids in the United States also confirms that the same endosymbionts found in Megacopta sp. in Japan. The two endysombionts are Candidatus Ishikawaella capsulata (gamma-proteobacterium in Enterobacteriales) and Wolbachia (alpha-proteobacterium in Rickettsiales) (Jenkins and Eaton 2011).

In Japan, there are two similar species of Megacopta - M. punctatissima and M. cribraria. Older literature suggested that M. punctatissima was a variety of M. cribraria, but they are now recognized as two different species (Eger et al. 2010). Megacopta punctatissima is a pest of soybean there in mainland Japan. However, Megacopta cribraria is found on Japanese islands and is not known to be an agricultural pest there. These two species have the same morphological characteristics. Though M. punctatissima and M. cribraria do not possess the same gut symbiotic bacteria. The symbiotic bacteria of M. punctatissima allows for digestion of legumes whereas the symbiotic bacteria of M. cribraria does not. In the United States, bean plataspid populations possess gut symbiotic bacteria capable of breaking down legumes and are a pest of soybean and other legumes. Despite differences in behaviors and symbiotic bacteria, the identification of M. cribraria in the United States is confirmed by molecular characteristics previously reported in native regions.

Synonymy

Cimex cribraria Fabricius 1798

Tetyra cribraria Fabricius 1803

Thyreocoris cribrarius [sic] Burmeister 1835

Coptosoma cribrarius Fabricius 1843

Coptosoma xanthochlora Walker 1867

Megacopta cribraria Hsiao and Ren 1977

Distribution

Before the introduction of the bean plataspid to the United States, species of the family Plataspidae were confined to the Old World - those parts of the world consisting of Europe, Africa, and Asia. The native distribution of the bean plataspid includes Australia, China, India, Indonesia, Japan, Korea, Malaysia, Myanmar, New Caledonia, Pakistan, Sri Lanka, Taiwan, Thailand, and Vietnam (Eger et al. 2010).

During October 2009, specimens and photos of the bean plataspid from infested homes were submitted from various locations across northeast Georgia . The specimens and photos were identified by morphological characteristics and molecular, DNA-based diagnosis. After the initial discovery, the bean plataspid was reported from nine counties in northeast Georgia (Suiter et al. 2010b). By the following year, the bean plataspid was reported from 80 counties in Georgia and 16 counties from South Carolina (Jenkins and Eaton 2011). Currently, the bean plataspid is reported in the following states: Alabama, northern Florida, Georgia, South Carolina, North Carolina, and southern Virginia.

Figure 1. 

The current distribution of the bean plataspid, Megacopta cribraria (Fabricius), in the United States as of 17 May 2012.


Credit:

Wayne A. Gardner, University of Georgia


[Click thumbnail to enlarge.]

Description

Adults: The adults are small (3.5 - 6 mm) with a rounded oblong shape and live 23 to 77 days. The dorsal side of the insect is covered in numerous dark punctations and is typically light brown to olive green in color. The scutellum (posterior plate along the dorsal side of the thorax) is enlarged and covers the forewings and most of the abdomen—this is characteristic of plataspids, as well as scutellerids (shield-back bugs) and thyreocorids. More common stink bugs tend to have a triangular shaped scutellum. The scutellum is also truncated with a flattened posterior end, a characteristic unique to this species when compared to other stink bugs in North America. The most distinguishing characteristics of the bean plataspid include its size, two-segmented tarsi, and enlarged, truncated scutellum (Eger et al. 2010).

Figure 2. 

Adult bean plataspids, Megacopta cribraria (Fabricius), on a building in Georgia, USA. Notice the enlarged, truncated scutellum covering the wings.


Credit:

Daniel R. Suiter, University of Georgia, http://www.bugwood.org


[Click thumbnail to enlarge.]

Eggs: Each egg mass has 26 to 274 eggs. The eggs tend to be a pale salmon color with dark bands intermediately spaced in a horizontal direction. The eggs are elongate and have a truncated ring of rugged projections at one end. Along with the eggs, females also deposit dark capsules underneath the eggs. These dark capsules are filled with endosymbionts (bacteria) that immature insects consume for nutritional development.

Figure 3. 

Egg mass of the bean plataspid, Megacopta cribraria (Fabricius), in a laboratory setting. Note the dark regions in the middle where the two rows of eggs meet, these dark regions are filled with endosymbionts.


Credit:

Paul Smith, University of Georgia, www.bugwood.org.


[Click thumbnail to enlarge.]

Nymphs: This species has five nymphal instars. Each nymphal instar takes two to 56 days to develop. Nymphs tend to have a hairy appearance and vary in color but tend to be pale orange, olive green, or light brown.

Figure 4. 

Multiple early instar nymphs of the bean plataspid, Megacopta cribraria (Fabricius), on kudzu, Pueraria montana var. lobata (Willd.) Maesen & S. Almeida.


Credit:

John Ruberson, University of Georgia, http://www.bugwood.org


[Click thumbnail to enlarge.]

Life Cycle

In its native habitat, there are up to three generations of the bean plataspid per year (Eger et al. 2010, Halbert and Eger 2010). The insect colonizes from April to July, forming large mating aggregations, and continues to be present until October. However, the bean plataspid may be active all year in warmer climates (Eger et al. 2010). As they go through reproductive diapause, adults overwinter on nearby buildings and structures, leaf litter, or under the bark of trees to keep warm.

Hosts

The primary hosts of M. cribraria in its native regions are legumes (Fabaceae): mainly soybean, Glycine max Merrill; kudzu, Pueraria montana var. lobata (Willd.) Ohwi; and lablab bean, Lablab purpureus (Linnaeus) Sweet. Megacopta cribraria is reported to develop only on soybean and kudzu in the United States. The adults and nymphs feed on the leaves, stem, flower, and pod of the host plant (Eger et al. 2010, Jenkins and Eaton 2011).

The following table is a compiled list of observed hosts of Megacopta spp. from past literature. Although additional plants other than legumes are listed, it is not confirmed if these plants are used as developmental hosts or if individual adults were observed simply perched on these plants.

Economic Importance

In its native regions, M. cribraria is not an agricultural pest. However in the United States, the bean plataspid is reported to be a pest of soybean in Georgia and South Carolina. The nymphs and adults congregate in high numbers and feed on the underside of leaves and the stem of the plant. Feeding damage results in abnormal pod development and necrotic areas on the plant.

Figure 5. 

Infestation of adult bean plataspids, Megacopta cribraria (Fabricius), on soybeans, Glycine max (L.) Merr., in Georgia, USA.


Credit:

Philip Roberts, University of Georgia, http://www.bugwood.org


[Click thumbnail to enlarge.]

Figure 6. 

Infestation of adult bean plataspids, Megacopta cribraria (Fabricius), on corn, Zea mays L., near Athens, Georgia, USA. A grasshopper is in the upper right corner.


Credit:

Jeremy Greene, Clemson University, http://www.bugwood.org


[Click thumbnail to enlarge.]

Adults from established bean plataspid populations within the United States are reported to overwinter on light colored structures, in leaf litter, and underneath the bark of trees. These insects are attracted to light colored surfaces, predominately white and yellow (Horn and Hanula 2011). Also, like stink bugs, adults tend to excrete an odor as a defense mechanism when disturbed. The defense chemical these insects secrete may stain the surface of the house, building or vehicle where aggregation occurs.

Figure 7. 

Infestation of adult bean plataspids, Megacopta cribraria (Fabricius), on a house in Georgia, USA. Megacopta cribraria have an overwintering stage during their life cycle and tend to swarm to nearby buildings during the overwintering period.


Credit:

Daniel R. Suiter, University of Georgia, http://www.bugwood.org


[Click thumbnail to enlarge.]

Survey and Management

Horn and Hanula (2011) are developing monitoring traps using light colors (i.e. white or yellow) to attract adult specimens. These monitoring traps may be a good tool to survey for bean plataspid. Sweep netting and hand-picking, although time consuming, are also good methods for surveying. For more information about surveying in your area, contact your local county Cooperative Extension Service (CES) agent.

Pyrethroids may be effective for temporary relief. Contact your local county CES agent for proper pest treatment methods.

As this insect moves from overwintering sites in search of food, the bean plataspid may become a nuisance pest in and around structures. Homeowners should ensure screening is placed over possible entries points of insects and that windows and doors are tightly sealed.

Acknowledgements

The authors extend their appreciation to Wayne A. Gardner, of the University of Georgia, for his review of this publication.

Selected References

  • Akin S, All J, Allen C, Boerma R, Buntin D, Cardinal A, Catchot A, Chen P, Clough S, Cook D, Davis J, Dively G, Greene J, Herbert A, Herbert J, Heitholt J, Jones W, Leonard R, Lorenz G, Miranda L, Musser F, Reed T, Reisig D, Roberts P, Smith R, Stewart S, Way M. (May 2011). A strategy for prioritizing research goals and outreach plans to reduce soybean production losses caused by stink bugs and related insect pests. SoyBase and the Soybean Breeder's Toolbox. http://soybase.org/StinkBugStratPlan/StkBgWhtPpStratPlan4May2011Final.pdf (25 May 2012).

  • Eger Jr JE, Ames LM, Suiter DR, Jenkins TM, Rider DA, Halbert SE. 2010. Occurrence of the Old World bug Megacopta cribraria (Fabricius) (Heteroptera: Plataspidae) in Georgia: a serious home invader and potential legume pest. Insecta Mundi 0121: 1-11.

  • FDACS. (August 2011). Field Crops. pp. 30-41, In 2011 - Florida agriculture by the numbers. Florida Department of Agriculture and Consumer Services. http://www.florida-agriculture.com/brochures/P-01304.pdf (25 May 2012).

  • Halbert S, Eger Jr JE. (March 2010). Bean plataspid, Megacopta cribraria (Fabricius) (Hemiptera: Plataspidae) an exotic legume pest established in Georgia. FDACS-Division of Plant Industry. http://www.freshfromflorida.com/pi/pest-alerts/megacopta-cribraria.html (25 May 2012).

  • Horn S, Hanula JL. 2011. Influence of trap color on collection of the recently-introduced bean plataspid, Megacopta cribraria (Hemiptera: Plataspidae). Journal of Entomological Science 46: 85-87.

  • Jenkins TM, Eaton TD. 2011. Population genetic baseline of the first plataspid stink bug symbiosis (Hemiptera: Heteroptera: Plataspidae) reported in North America. Insects 2: 264-272.

  • Jenkins TM, Eaton TD, Suiter DR, Eger Jr JE, Ames LM, Buntin GD. 2010. Preliminary genetic analysis of a recently-discovered invasive true bug (Hemiptera: Heteroptera: Plataspidae) and its bacterial endosymbiont in Georgia, USA. Journal of Entomological Science 45: 1-2.

  • Suiter DR, Eger Jr JE, Gardner WA, Kemerait RC, All JN, Roberts PM, Greene JK, L. Ames M, Buntin GD, Jenkins TM, Douce GK. 2010a. Discovery and distribution of Megacopta cribraria (Hemiptera: Heteroptera: Plataspidae) in northeast Georgia. Journal of Integrated Pest Management 1: 1-4.

  • Suiter DR, Ames LM, Eger Jr JE, Gardner WA. (September 2010b). Megacopta cribraria as a nuisance pest. Urban Entomology Pest Series. UGA-CAES Publications. http://www.caes.uga.edu/Publications/pubDetail.cfm?pk_id=7891 (25 May 2012).

Tables

Table 1. 

Hosts of Megacopta spp. (Eger et al. 2010)

Family

Common Name

Scientific Name

Acanthaceae

firecracker plant

Crossandra infundibuliformis (Linnaeus) Nees

Convolvulaceae

sweet potato

Ipomoea batatas (Linnaeus) Lamarck

Fabaceae

agathi

Sesbania grandiflora (Linnaeus) Pers.

Fabaceae

azuki bean

Vigna angularis (Willd.) Ohwi and Ohashi

Fabaceae

bean

Phaseolus spp.

Fabaceae

broad bean

Vicia faba Linnaeus

Fabaceae

Chinese milk vetch

Astragalus sinicus Linnaeus

Fabaceae

cluster bean

Cyamopsis tetragonoloba (Linnaeus) Taubert

Fabaceae

Indian beech tree

Millettia pinnata (Linnaeus) Pierre

Fabaceae

indigo

Indigofera sp.

Fabaceae

kidney bean

Phaseolus vulgaris Linnaeus

Fabaceae

kudzu

Pueraria montanavar.lobata (Willd.) Ohwi

Fabaceae

lablab bean

Lablab purpureus (Linnaeus) Sweet

Fabaceae

lespedeza

Lespedeza cyrtobotra Miquel

Fabaceae

lima bean

Phaseolus lunatus Linnaeus

Fabaceae

mung bean

Vigna radiata (Linnaeus)

Fabaceae

pigeon pea

Cajanus indicus Spreng

Fabaceae

soybean

Glycine max Merrill

Fabaceae

urd-bean

Vigna mungo (Linnaeus) Hepper

Fabaceae

velvet bean

Mucuna pruriens (Linnaeus)

Fabaceae

vetch

Vicia angustifolia Linnaeus

Fabaceae

wisteria

Wisteria brachybotrys Siebold et Zuccarini

Hydrangeaceae

deutzia

Deutzia crenata Siebold and Zuccarini

Malvaceae

cotton

Gossypium hirsutum Linnaeus

Malvaceae

jute

Corchorus capsularis Linnaeus

Moraceae

white mulberry

Morus alba Linnaeus

Oleaceae

Chinese privet

Ligustrum sinense Loureiro

Poaceae

rice

Oryza sativa Linnaeus

Poaceae

sugarcane

Saccharum officinarum Linnaeus

Poaceae

wheat

Triticum aestivum Linnaeus

Rutaceae

citrus

Citrus

Solanaceae

horsenettle

Solanum carolinense Linnaeus

Solanaceae

potato

Solanum tuberosum Linnaeus

Footnotes

1.

This document is EENY-413 (IN939), one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: June 2012. Revised April 2013. This document is also available on Featured Creatures website at http://entomology.ifas.ufl.edu/creatures. Please visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Ashley Poplin, graduate student; and Amanda Hodges, SPDN assistant director in entomology and training/education, Department of Entomology and Nematology; Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.