ArticlePDF Available

The Erythrina Stem or Twig borer: A new and Potentially Devastating Pest of Coral Trees in California

Authors:
  • Los Angeles County Department of Agricultural Commissioner
The Erythrina Stem or Twig Borer
A New and Potentially Devastating Pest of Coral Trees in California
Donald R. Hodel, James E. Henrich, Kenneth J. Greby,
Gevork Arakelian, Linda M. Ohara, and Surendra K. Dara
The Erythrina stem borer (ESB)
(sometimes known as the Erythrina twig
borer) (Terastia meticulosalis), a potentially
devastating pest of Erythrina spp. (coral
trees), has been sighted numerous times in
southern California in the latter half of 2015
from San Diego to Ventura. Erythrina, a
member of the Fabaceae (formerly
Leguminosae, bean family) encompasses
about 112 species (Bruneau 1996) and
includes some of our most useful, valuable,
well adapted, and spectacular flowering trees,
Figure 1. Erythrina caffra is one of our most handsome, spring-flowering trees. Santa Barbara, CA. (D. R. Hodel).
Figure 2. Another striking landscape tree is
Erythrina coralloides (Huntington Beach, CA. (D.
R. Hodel).
PalmArbor 2016-1: !-101
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
adorning landscapes along the coast and
adjacent plains and valleys in southern
California (Figs. 1-5). Indeed, a famous
planting of E. caffra adorning the broad
median of San Vicente Boulevard in Santa
Monica and West Los Angeles was designated
an exceptional planting (Fig. 6) (Hodel 1988).
The plethora of sightings suggests a more
recent introduction but the ESB was recorded
as early as 1973 at Fort Piute in the California
desert north of Needles near the southern tip
of Nevada (CMSD 2016).
The ESB is of special concern for us
because so little is known about its
management and it appears to be especially
destructive on coral trees, infesting seeds,
destroying branch tips, and even killing whole
plants. In Florida where it is native, it is a
serious pest of naturally occurring and exotic
coral trees, which are valued for agriculture,
medicine, and landscape ornament (Powell
and Westley 1993). Indeed, the cultivation of
exotic coral trees in Florida is essentially
impossible because of the ESB (Raven 1974);
the only coral tree that can be cultivated
PalmArbor 2016-1: !2
Figure 3. Erythrina crista-galli is a handsome
landscape tree. The Los Angeles County Arboretum
& Botanic Gardens, Arcadia, CA (D. R. Hodel).
Figure 4. Erythrina humeana is an attractive, late
summer –flowering tree. Santa Barbara, CA. (D. R.
Hodel).
Figure 5. This gorgeous Erythrina lysistemon makes
a statement in the spring. Golden West College,
Huntington Beach, CA. (D. R. Hodel).
Figure 6. This planting of Erythrina caffra in the
median of San Vicente Blvd. was designated an
exceptional planting in 1988. (D. R. Hodel).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
reliably there is the native Erythrina
herbacea, which likely co-evolved with and is
found over most of the range of the ESB. In
California the ESB has been observed so far
on E. × bidwillii, E. chiapasana, E.
coralloides, E. crista-galli, and E. falcata;
other species will likely be added in the
future. Although much remains to be know
about the ESB in California, at least at this
early stage, the ESB seems to prefer species
of coral trees with more slender stems and
slender regrowth of larger-stemmed species.
Fortunately, another serious pest of
coral trees that is sympatric and co-evolved
with the ESB, the Erythrina leaf roller
(Agathodes designalis), has not yet been
detected in California. The Erythrina leaf
roller and the ESB are in closely related
genera that have tended to niche-partition the
coral tree resource to reduce inter-species
competition (Armstrong and McGehee 1980,
Sourakov 2011).
Much remains to be known about the
natural history of the ESB, and the summary
we provide here of its taxonomy,
identification, distribution, and life cycle and
damage it inflicts on coral trees is mostly
from Arakelian (2016), Sourakov (2011,
2012, 2013), Sourakov et al. (2015), and our
observations of infested coral trees here.
Taxonomy
The ESB is one of five species in the
largely tropical moth genus Terastia, which
ranges from the Americas to Africa, Asia, and
the western Pacific (Sourakov et al. 2015).
The ESB is the only species of the genus
native to the Americas. The other four species
are T. africana, T. egialealis (Africa), T.
margaritis (India), and T. subjectalis (Asia
and western Pacific).
Identification
The adult ESB is a small-sized,
brownish moth with mottled forewings and
whitish hindwings with dark margins (Figs.
7-8). Varying in size, adult forewing
wingspans range from 2.5 to 4.6 cm, and the
PalmArbor 2016-1: !3
Figure 7. The adult Erythrina stem borer is a small-
sized, brownish moth with mottled forewings and
whitish hindwings with dark margins. (A. Sourakov).
Figure 8. With unspread, mottled-brown wings the
adult Erythrina stem borer is easy to miss. Note the
upward-curved and knobby abdomen. The Los
Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
mottled body from 1.5 to 2.5 cm long, the
latter with conspicuous knobs toward the
posterior (Fig. 9) (Sourakov et al. 2015). In
Florida the ESB varies greatly in size, which
largely depends on the seasonal generation
and diet. The spring generation, which feeds
mostly on seeds, is larger than the fall and
summer generation that feeds inside of stems.
For example, wingspans of the spring
generation average about 3.7 cm while those
of the summer and fall generations average
about 3cm and 2.5 cm respectively (Sourakov
2011). When at rest, the mottled- or marble-
brown forewings are effective at
camouflaging the ESB but when the wings
are spread the white hind wings are
conspicuous.
Males and females are similar but the
latter has more beige-brown forewing
markings. In live specimens, the knobby
abdomen is held in a curved, upright position,
mimicking a praying mantis head, which is
possibly a deterrent to predators (Fig. 10)
(Sourakov et al. 2015).
Eggs of the ESB, typically laid singly
in the axil of leaves near stem tips (Fig. 11),
are translucent, white, delicate, dome-shaped
with a reticulated surface, and about 0.8 mm
long (Sourakov 2012). Young larvae are
minute, about 0.5 mm long, and probably
burrow directly into the flower, stem, or
sometimes even a leaf petiole and then follow
it to the stem.
Larvae of the ESB are translucent and
brownish white or cream-colored with a black
sclerotized head and a dark sclerotized
prothoracic plate that becomes lighter as the
larva matures (Fig. 12). Mature larvae are
about 4 cm long. Larvae turn pinkish before
pupation (Fig. 13), especially when they
complete their development on seeds. Pupae
are cigar-shaped, light brown, and enclosed in
a loose, double-layered cocoon (Figs. 14-15)
(Sourakov 2011).
PalmArbor 2016-1: !4
Figure 9. Note the knobby posterior end of the
abdomen of this adult Erythrina stem borer. (A.
Sourakov).
Figure 10. In live specimens, the knobby abdomen
of the Erythrina stem borer is held in a curved,
upright position, mimicking a praying mantis head,
which is likely a deterrent to predators. (A.
Sourakov).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
PalmArbor 2016-1: !5
Figure 11. Eggs of the Erythrina stem borer,
typically laid singly in the axil of leaves near stem
tips), are translucent and white. (A. Sourakov).
Figure 12. Larvae of the Erythrina stem borer have
cream-colored bodies and a black head. The Los
Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
Figure 13. Larvae of the Erythrina stem borer that
feed on seeds typically take on a pinkish hue. The
Los Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
Figure 14. Pupae of the Erythrina stem borer are
cigar-shaped and light brown. (A. Sourakov).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
PalmArbor 2016-1: !6
Figure 15. Pupae of the Erythrina stem borer are
enclosed in a loose, double-layered cocoon, as in
this captive-reared specimen. The Los Angeles
County Arboretum & Botanic Gardens, Arcadia, CA
(D. R. Hodel).
Figure 16. The downward-boring larvae of the
Erythrina stem borer feed internally on stem tissues
near the shoot tips (Erythrina coralloides). The Los
Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
Figure 17. Larvae of the Erythrina stem borer
hollow out the stem as they feed (Erythrina
coralloides). The Los Angeles County Arboretum &
Botanic Gardens, Arcadia, CA (D. R. Hodel).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
PalmArbor 2016-1: !7
Figure 18. Dying-off of stem tips, which turn black
and sometimes collapse, is characteristic of the
Erythrina stem borer (Erythrina chiapasana). The
Fullerton Arboretum, California State University,
Fullerton, CA (D. R. Hodel).
Figure 19. Dying-off of stem tips, which turn black
and sometimes collapse, is characteristic of the
Erythrina stem borer (Erythrina × bidwillii). The
Los Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
Figure 20. Larvae of the Erythrina stem borer can
also attack seed pods (Erythrina crista-galli). The
Los Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
Management
Unfortunately, next to nothing is
known about the management of the ESB.
Nearly all attempts at post-infestation
eradication in Florida have failed. Virtually
nothing is known about resident natural
enemies although they must be present; until
they are identified biological control holds
little promise. Perhaps vigilant scouting,
judicious and immediate removal, bagging,
and disposal of infested shoot tips, and
ground and foliar treatment with systemic
pesticides might be effective and justified for
rare, exceptional, and/or noteworthy and
valuable coral tree specimens. Because the
ESB pupates in leaf litter on the ground,
thorough raking and disposal of fallen leaves
might reduce regeneration and provide some
control. Cover/barrier insecticides, like
pyrethroids (permethrin, cyfluthrin,
bifenthrin) or emulsifiable concentrate
formulation of carbaryl, might work well in
killing of newly hatched larvae when they
attempt to bore into the stems; although not
yet tested for ESB, they have relatively long
residual effects and might be effective.
Further work is needed on this pest that poses
a serious threat to California’s ornamental
landscape coral trees.
PalmArbor 2016-1: !8
Figure 21. Larvae of the Erythrina stem borer can
also attack seed pods (Erythrina crista-galli). The
Los Angeles County Arboretum & Botanic Gardens,
Arcadia, CA (D. R. Hodel).
Figure 22. Larvae of the Erythrina stem borer
typically purge the hollowed out stem of frass by
crawling backwards to the entry hole to defecate
(Erythrina coralloides). The Los Angeles County
Arboretum & Botanic Gardens, Arcadia, CA (D. R.
Hodel).
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
Acknowledgements
We thank Andrei Sourakov of the University of Florida for reviewing this paper and
providing some of the images. Readers interested in supporting his important work can contact
Andrei directly (asourakov@flmnh.ufl.edu).
Literature Cited
Arakelian, G. 2016. Erythrina Stem Borer (Terastia meticulosalis). L. A. County Dept. Agri.
Comm./Weights Measures Pest Note.
Armstrong, R. A. and R. McGehee. 1980. Competitive exclusion. Amer. Naturalist 115: 151-170.
Bruneau, A. 1996. Phylogenetics and biogeographical patterns in Erythrina (Leguminosae:
Phaseoleae) as inferred from morphological and chloroplast DNA characters. Syst. Bot.
21(4): 587-605.
CMSD. 2016. California Moth Specimens Database. On-line: https://essigdb.berkeley.edu/cgi//
calmoth_query?stat=BROWSE&query_src=eme_BrowseCalmothNames&where-
genus=Terastia. Accessed 5 January 2016.
Hodel, D. R. 1988. Exceptional Trees of Los Angeles. California Arboretum Foundation, Arcadia.
Powell, M. H. and S. B. Westley. 1993. Erythrina Production and Use: A Field Manual.
Nitrogen Fixing Tree Association, Paia, HI.
Raven, P. H. 1974. Erythrina (Fabaceae): achievements and opportunities. Lloydia 35: 321-331.
Sourakov, S. 2011. Niche-partitioning, co-evolution and life histories of erythrina moths,
Terastia meticulosalis and Agathodes designalis (Lepidoptera: Crambidae). Trop. Lepid.
Res. 21(2): 89-94.
Sourakov, A. 2012. On the biology of moths that feed on Erythrina in Florida. Trop. Lepid. Res.
22(2): 110-118.
Sourakov, A. 2013. Erythrina moths Terastia meticulosalis Guenée and Agathodes designalis
Guenée. Department of Entomology, Florida Cooperative Extension Service, Institute of
Food and Agricultural Sciences, University of Florida, Publ. EENY 516. Available on-
line: http://edis.ifas.ufl.edu/in921.
Sourakov, A., D. Plotkin, A. Y. Kawahara, L. Xiao, W. Hallswachs, and D. Janzen. 2015. On the
taxonomy of the erythrina moths Agathodes and Terastia (Crambidae: Spilomelinae):
PalmArbor 2016-1: !9
PalmArbor Hodel et al.: Erythrina Stem Borer Vol. 2016-1 2016
Two different patterns of haplotype divergence and a new species of Terastia. Trop.
Lepid. Res. 25(2): 80-97.
Swezey, O. H. 1923. The Erythrina twig borer (Terastia meticulosalis) in Hawaii (Pyralidae,
Lepidoptera. Proc. Hawaiian Ent. Soc. 5(2): 297-298.
Zimmerman, E. L. 1958. Insects of Hawaii. Vol. 8 (Lepidoptera: Pyraloidea). University of
Hawaii Press, Honolulu.
_______________
Donald R. Hodel is landscape horticulture advisor for the University of California Cooperative
Extension in Los Angeles. drhodel@ucanr.edu.
James E. Henrich is curator of living collections at the Los Angeles County Arboretum &
Botanic Garden in Arcadia, CA. jim.henrich@arboretum.org.
Kenneth J. Greby is an arborist with ArborPro in Yorba Linda, CA. fastfeat@gmail.com.
Gevork Arakelian is the entomologist with the Los Angeles County Agricultural Commissioner/
Weights & Measures in South Gate, CA. GArakelian@acwm.lacounty.gov.
Linda M. Ohara is a biology sciences lab technician at El Camino College in Torrance, CA, a
horticulturist, and a former nurserywoman. lohara@elcamino.edu.
Surendra K. Dara is IPM advisor for the University of California Cooperative Extension in
Ventura, CA. skdara@ucanr.edu.
PalmArbor 2016-1: !10
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
The life histories of the erythrina leafroller, Agathodes designalis, and the erythrina stem-borer, Terastia meticulosalis from north central Florida are described and illustrated, complementing previous literature accounts. It is proposed that competition among larvae of these two crambid moths has resulted in ecological niche partitioning. In the studied populations, both species feed on the coral bean, Erythrina herbacea, and each species occupies different parts of the plant and different plants in the ecosystem. Larval behavior and morphology are consistent with adaptation for resource partitioning. Distribution, hostplant and life history information are compiled from the literature, with a special emphasis on the economic importance of T. meticulosalis throughout the tropical and subtropical regions of the world, where this species and its sister species, T. subjectalis, attack a variety of Erythrina species. In Florida, both species are multivoltine and their life history varies between generations, suggesting adaptation to changes in environmental and hostplant conditions. The co-evolution of these moths in association with the diverse, pan-tropical genus Erythrina is proposed and discussed.
Article
Full-text available
New studies on the life histories of erythrina leafroller Agathodes designalis, and erythrina borer Terastia meticulosalis (Crambidae), conducted in Florida, complement previous literature accounts. Specifically, oviposition, egg morphology, survival of larvae, and pupation behavior of these two closely related species are discussed. Another unrelated micro-moth species - erythrina leafminer, Leucoptera erythrinella (Lyonetiidae) - also uses coral bean as its hostplant, utilizing this resource in a manner that minimizes interspecific competition witht the abovementioned crambids. New studies on life history of L. erythrinella are presented, including illustrations of the immature stages, and sexual dimorphism.
Article
The seven papers that follow present an up-to-date review of the botany of Erythrina (Fabaceae-Faboideae), including morphology, distribution, palynology, chromosome number, alkaloids, and amino acids. This much-studied genus of 108 species of trees, shrubs, and a few herbs, and of wide distribution in the warm parts of the World, has been divided for the first time consistently into 26 sections assigned to five subgenera. The flowers of all but one species (which are green) are red, scarlet, or orange and so constructed that outcrossing is universal; two species are reported to be genetically self-incompatible. There appear to be no barriers to interspecific hybridization except ecological/geographical ones, and all species are pollinated by birds, which are not known to discriminate between them. Hybrids are frequent in cultivation and where species come together in nature, and hybridization seems to have played a central role in the evolution of the genus. The nature and extent of polyploidy in the genus should be reexamined. Its reticulate pattern of evolution is reflected in its morphology, palynology, amino acids, and alkaloids. So much is now known about Erythrina that it is an ideal model group for evolutionary studies, including biosystematic ones and those involving predator-prey relationships, and an even more detailed knowledge of it should illuminate the kinds of evolutionary pattern found in many other less well studied groups of plants. The large collection of living plants being assembled at the Pacific Tropical Botanical Garden in Kauai should provide an excellent basis for many such studies.
Article
A cladistic analysis is presented for a subset of 51 species of Erythrina (Leguminosae: Phaseoleae) representing the morphological, ecological and geographical diversity of the genus. The results are similar to a previously published cladistic analysis of chloroplast DNA restriction site characters. The combined analysis supports as monophyletic subg. Erythraster, but suggests that subg. Micropteryx, Erythrina and Chirocalyx are paraphyletic. At the sectional level, several of the traditionally recognized groups are supported as monophyletic. A paraphyletic assemblage of South American elements are basal in the genus. From this group are derived two main clades. One comprises South American and Mexican taxa. The other includes Asian species from which are derived a New World group and a primarily African clade, with derived Asian and South American species. Biogeographical patterns, fossil evidence, and the probable age of avian pollinators suggest a possible Early Tertiary occurrence in North America, with subsequent diversification in South America, Africa, and Asia.
Exceptional Trees of Los Angeles. California Arboretum Foundation
  • D R Hodel
Hodel, D. R. 1988. Exceptional Trees of Los Angeles. California Arboretum Foundation, Arcadia.
Erythrina Production and Use: A Field Manual. Nitrogen Fixing Tree Association
  • M H Powell
  • S B Westley
Powell, M. H. and S. B. Westley. 1993. Erythrina Production and Use: A Field Manual. Nitrogen Fixing Tree Association, Paia, HI.
Erythrina moths Terastia meticulosalis Guenée and Agathodes designalis Guenée. Department of Entomology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences
  • A Sourakov
Sourakov, A. 2013. Erythrina moths Terastia meticulosalis Guenée and Agathodes designalis Guenée. Department of Entomology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Publ. EENY 516. Available online: http://edis.ifas.ufl.edu/in921.
Lepidoptera: Pyraloidea)
  • E L Zimmerman
Zimmerman, E. L. 1958. Insects of Hawaii. Vol. 8 (Lepidoptera: Pyraloidea). University of Hawaii Press, Honolulu.