Lymantria mathura

 
IDENTITY
Name:   Lymantria mathura
Pest Authorities:  Moore
Taxonomic Position:  Insecta: Lepidoptera: Lymantriidae
Sub-specific Taxon:  
Pest Type:   Insect
Common Name(s):
   Pink gypsy moth (English)
   Rosy gypsy moth (English)
   Russian gypsy moth (English)
   Sal defoliator (English - common name used in India)
   Spongieuse rose (French)
Synonym(s):
 
RISK RATING SUMMARY
Numerical Score:  9
Relative Risk Rating:  Very High Risk
Uncertainty:   Very Certain
RISK RATING DETAILS
Establishment Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Suitable climatic conditions and suitable host material coincide with ports of entry or major destinations.
  • Organism has active, directed host searching capability or is vectored by an organism with directed, host searching capability.
  • Organism has high inoculum potential or high likelihood of reproducing after entry.
Justification: Lymantria mathura would find suitable climatic conditions at many North American ports of entry. Since this insect prefers to feed on plants in the family Fagaceae (e.g. oaks), it would find an abundance of potential host plants in the forests of eastern North America and much of the Pacific Coast region. If introduced, it would have a high likelihood of reproducing.

Spread Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Organism is capable of dispersing more than several km per year through its own movement or by abiotic factors (such as wind, water or vectors).
  • Organism has a high reproductive potential
  • Potential hosts have contiguous distribution.
  • Eradication techniques are unknown, infeasible, or expected to be ineffective.
  • Organism has broad host range.
Justification: Both male and female adults are capable of flying and could disperse over distances of several km either on their own or assisted by air currents. Early instar larvae are also subject to dispersal by air currents. This insect has a high reproductive potential and during outbreaks, females tend to lay eggs indicriminantely on a variety of sites including ships and products destined for export. Egg masses of Lymantria mathura have been found on ships arriving in North America from the Russian Far East (Baranchikov et al. 1995).

If successfully introduced, this insect has the potential to spread over the full range of its potential hosts in North America. Early detection would be difficult unless specific surveys are conducted. Defoliation caused by this insect could be easily confused with that of native broadleaf defoliators or the already established gypsy moth, Lymantria dispar.

Economic Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Organism attacks hosts or products with significant commercial value (such as for timber, pulp, or wood products.
  • Organism directly causes tree mortality or predisposes host to mortality by other organisms.
  • Damage by organism causes a decrease in value of the host affected, for instance, by lowering its market price, increasing cost of production, maintenance, or mitigation, or reducing value of property where it is located.
  • Organism may cause loss of markets (domestic or foreign) due to presence and quarantine significant status.
Justification: In its native range, the rosy gypsy moth is a defoliator of valuable forest tree species, such as oaks. Other species in the genus Lymantria have had significant impacts on forest health and L. mathura is likely to do so in North America. However, the relative lack of literature on L. mathura outbreaks makes accurate assessment of its potential economic impact difficult.

Environmental Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Organism is expected to have direct impacts on species listed by Federal, Provincial, or State agencies as endangered, threatened, or candidate. An example would be insuring a listed plant species.
  • Organism may attack host with small native range.
  • Introduction of the organism would likely result in control/eradication programs that may have potential adverse environmental affects.
Justification: Oaks, beeches and other potential host trees provide important food crops for wildlife. Physiological stress from defoliation could adversely affect mast production, which could be detrimental to wildlife populations. Defoliated trees can refoliate, so any potential loss of foliar shelter would be temporary. Introduction and establishment of Lymantria mathura in North America would result in increased use of biological and chemical insecticides with accompanying undesireable effects on non-target organisms.

 
HOSTS
Lymantria mathura larvae are polyphagous and feed on 13 to 20 families of primarily deciduous trees. These families include the Fagaceae (oaks and beeches), Salicaceae (willows), Rosaceae (fruit trees) Betulaceae (birches), Juglandaceae (hickories and walnuts), Oleaceae (ashes) and a number of tropical families of trees (Baranchikov et al. 1995, Dey and Tiwari 1997, Zlotina et al. 1998).

Recorded hosts in India include Antocephalus cadamba, Mangifera indica, Quercus incana, Quercus serrata, Shorea robusta, Syzygium cuminii, Terminalia arunja and Terminalia myriocarpa (Browne 1968). In Honk Kong, Mangifera indica, Lichi chinensis and Liquidambar formosana are hosts (Mohn 2001), in China and Korea, Castania sp. and Castanea mollisima are hosts, (Lee and Lee, 1996; Zheng et al. 1994) and in Russia, Quercus mongolica is a reported host (Yurkchenko et al. 2000).

Lymantria mathura larvae can also survive on conifer foliage. Larvae reared on plants of the Pinaceae genera Abies, Pinus and Larix performed poorly with less than 13% survivorship. However, larvae reared on Douglas-fir, Pseudotsuga menziesii, averaged 33% survivorship (Zlotina et al. 1998).

 
GEOGRAPHICAL DISTRIBUTION
Asia:
     This insect is found in China, including Hong Kong and northeast China, Bangladesh, India, Japan, Korea, Pakistan, Taiwan, and the Russian Far East.
 
BIOLOGY
The genus Lymantria consists of at least 17 species of broadleaf and conifer defoliating insects, two of which are of major economic importance: the gypsy moth, L. dispar and the nun moth, L. monacha. Most species are found on the Indian subcontent. This genus is not represented among the native Lymantriid fauna in North America although L. dispar has been introduced and is now a major forest pest (Browne 1968).

Two subspecies of Lymantria mathura are recognized, L. mathura aurora from Japan and Korea (Schaefer and Ikebe 1992, Lee and Lee 1996) and L. mathura subpallida from Taiwan (http://www.geocities.com/felix33w/native.39.html). Populations from China, Russia, India and Bangladesh are simply referred to as L. mathura.

Lymantria mathura has one generation per year in Japan and Korea, two in India and possibly three in Hong Kong (Dey and Tiwari 1997, Kendrick in press). In the univoltine populations Lymantria mathura overwinters as egg masses. First instar larvae hatch in May and emergence of adults from pupal cases occurs from mid August to mid September. An average of 258 eggs/mass are deposited in crevices on tree boles and are covered with anal tuft scales. Choice of oviposition site becomes indiscriminant during outbreaks (Lee and Lee 1996, Dey and Tiwari 1997, Pucat and Watler 1997).

In India larvae appear in April and in June-July. The second generation overwinters as egg masses. Larvae tend to be gregarious (Browne 1968) and have six instars. They are nocturnal and congregate low on tree boles during the day (Dey and Tiwari 1997). Early instar larvae often prefer to feed on flowers of host plants and later switch to foliage. They can also injure the bark of young shoots (Browne 1968). The larvae undergo unusual movements, referred to as a “dance,” throughout the feeding cycle. They hold on to a branch with their prolegs and repeatedly arch of bend both the head and tail segments to touch. The reason for this behavior is unclear but could be a defensive response to natural enemies (Mohn 2001).

Pupation occurs in leaves sealed with silken webbing, and adults are abundant in May and October. Larvae from both generations are active nocturnally, congregating low on tree boles during the day (Dey and Tiwari 1997). Adults of both sexes fly (Wallner et al. 1995, Oliver et al. 1997). Cotesia melanoscelus (Hymenoptera: Braconidae) and Brachymeria lasus (Hymenoptera: Chalcididae) are the major larval and pupal parasitoids, respectively, in Korea. A total of nine parasitoids have been reported from Korea, and two pathogens, a nuclear polyhedris virus (NPV) and a fungus Beauvaria sp. (Lee and Lee 1996). Other parasites reported from Lymantria mathura are Carcelia excavata (Diptera: Tachinidae), and a nematode, Hexamermis sp. (Nematoda: Mermithidae), both from Japan (Togashi 1978, Schaefer and Ikebe 1982).

 
PEST SIGNIFICANCE
Economic Impact:    The rosy gypsy moth is a forest defoliator. Outbreaks in Russia are not well documented but can be extensive. Sometimes Lymantria mathura outbreaks in Russia are concurrent with those of the Asian gypsy moth, Lymantria dispar. Little is known about the subsequent effects of rosy gypsy moth defoliation on forest health (Baranchikov et al. 1995, Zlotina et al. 1998). In India outbreaks are infrequent but extensive when they do occur. No significant tree mortality occurs after defoliation of the sal tree, Shorea robusta, but tree vigor may be reduced and susceptibility to attack from other insect species may increase (Dey and Tiwari 1997).

Environmental Impact:   Reduction in tree vigor or health from defoliation may reduce mast production in host trees. Wildlife species that rely on beech nuts and acorns for a food source may be adversely affected. The impairment of tree health can make host species more susceptible to attack from other insect pest species (Dey and Tiwari 1997). In addition, introduction of this defoliator into North America would undoubtedly result in use of biological and chemical insecticides for eradication/suppression programs and accompanying adverse effects on non-target organisms.

Control:    The bacterial insecticide Bacillus thuringiensis has been aerially applied to an outbreak of Asian and pink gypsy moths but suppression was not successful (Anonymous 2001). Mechanical control methods, such as tree banding, can be used.

In the Russian Far East, ship and port lighting is known to attract females of Lymantria dispar, L. monacha and L. mathura. Reducing light in port areas during times of female flight activity can reduce the risk of egg masses being deposited on sea containers, other cargo and ships. Shipping companies and port operations are cooperating with the Russian Plant Quarantine Agency to reduce lighting based on flight periodicity data (USDA Forest Service, 2001).

 
DETECTION AND IDENTIFICATION
Symptoms:    Symptoms include defoliation of leaves and flowers (Pucat and Watler 1997) and the presence of insect life stages.

Morphology:    Eggs are deposited in masses of about 200 eggs each, usually in bark crevices. Egg masses are pale yellow in color when first laid and darken after about two weeks.

The larvae are stout bodied, ashy gray-brown in color with transverse yellow bans on the thorax. The entire body is covered with prominent bristles. They have one pair of anterior and two pairs of posterior hair pencils or long hair tufts. The larvae are about 3.4 mm long when first hatched, second instars are 5.8 mm long, third instars 2 cm long and fourth instars average 4 cm long. By the third instar, female larvae are significantly larger and faster growing than the males. Mature male larvae are about 4.2 cm long and females about 6 cm long (Mohn 2001).

Pupae are stout and medium brown in color. Male pupae average 2 cm in length and female pupae average 3 cm. The first abdominal segment has a pair of clusters of short white hairs (Mohn 2001).

The adults are moderate sized moths, which are hairy and heavy-bodied. The females bear a thick anal tuft of scale hairs and the last three abdominal segments are extended. The ovipositor of Lymantria mathura is elongated, but not as much as that of the nun moth, L. monacha. The hind wings of the female L. mathura are pink and those of the male are yellow. Female wingspan ranges from 75-95 mm and the male wingspan ranges from 35-46 mm.

Testing Methods for Identification:    Examination of adults by a taxonomist with expertise in the family Lymantriidae is required for positive identification.

 
MEANS OF MOVEMENT AND DISPERSAL
Adults of both sexes are capable of flight. Larvae are capable of ballooning, and egg masses are deposited in sheltered locations that lend themselves to human assisted means of transport (Zlotina et al. 1999). Egg masses of Lymantria mathura have been detected on ships and shipping containers coming from Russian ports (Baranchikov et al. 1995, Anonymous 2001).

Used motor vehicles are another human assisted means by which defoliators of the family Lymantriidae, including Lymantria mathura can be moved. In a study conducted between September 2000 and June 2002, 152 lymantriid interceptions (primarily the Asian form of Lymantria dispar) were made at New Zealand ports of entry. All but one of these interceptions was from used vehicles imported from Japan. Egg masses were the most common life stage intercepted although small numbers of larvae, pupae and adults were also detected (Armstrong et al., 2003).

 
BIBLIOGRAPHY
Anonymous. 2001. Russian Lymantria project. USFS Forest Health Protection Intermountain Region, Boise, Idaho. On-line: http://www.fs.fed.us/r4/health/bugcruds/weis_final.html.
Armstrong, K.F.; McHugh, P.; Chinn, W.; Frampton, E.R.; Walsh, P.J. 2003. Tussock moth species arriving on imported used vehicles determined by DNA analysis. New Zealand Plant Protection Society Incorporated, 56th Conference Proceedings.
Baranchikov, Y.; Vahivkova, T.; Montgomery, M. 1995. Suitability of foreign tree species for Lymantria mathura Moore. In: Fosbroke, S.L.C. and K.W. Gottschalk, eds. Proceedings, USDA Interagency Gypsy Moth Research Forum 1995. January 17-20, Annapolis, MD. Gen. Tech. Rep. NE-213. USDA Forest Service, Northeast Forest Experimental Station, Radnor, PA. 133 p.
Browne, F.G. 1968. Pests and diseases of forest plantation trees. Oxford: Clarendon Press, 1330 pp.
Dey, R.K.; Tiwari, K.P. 1997. Detection of an imminent defoliator attack on the borer infested sal forests of Madhya Pradesh. Vaniki Sandesh 21(4): 21-24.
Kendrick, R.C. 2002. (In press). The Moths (Insecta: Lepidoptera) of Hong Kong: Zoogeography, Phenology and Community Composition. 2002 Unpublished Ph.D. thesis. University of Hong Kong. Additional information available on-line at http://hkusub.hku.hk/~kendrick/hkmoth.htm.
Lee, J.H.; Lee, H.P. 1996. Parasites and phenology of Lymantria mathura Moore (Lymantriidae: Lepidoptera) in Kyonggi Province, Korea. Korean Journal of Entomology 26(4): 393-401. Cited in Review of Agricultural Entomology 85: 999 (1997).
Mohn, D.L. 2001. Rosy gypsy moth (Lymantriidae Lymantria mathura – Moore, 1865). Light Creations, On line: http:www.ccs-hk.org/DM/butterfly/ Lymantriid/Lymantra-mathura.html
Oliver, J.E.; Dickens, J.C.; Zlotina, M.; Mastro, V.M. 1997. Sex pheromone of the Russian gypsy moth, (Lymantria mathura Moore). US Department of Agriculture, Tektran Agricultural Research Service. On-line: http://gopher.nal.usda.gov/ttic/tektran/data/000008/49/0000084967.html.
Pucat, A.M.; Watler, D.M. 1997. Lymantria mathura Moore: Rosy (pink) gypsy moth. Plant Health Risk Assessment Unit. On-line: http://www.inspection.gc.ca/english/ppc/science/pps/datasheets/lymmate.shtml.
Schaefer, P.W.; Ikebe, K. 1982. Recovery of Hexamermis sp. (Nematoda: Mermithidae), paratizing gypsy moth, Lymantria dispar (L.), in Hokkaido, Japan. Environmental Entomology 11(3): 675-680.
Togashi, I. 1978. Tachinid flies (Diptera: Tachinidae) occuring in the chestnut orchards in Ishikawa Prefecture. (Insect fauna of chestnut orchards in Ishikawa Prefecture VI). Transactions of the Shikoku Entomological Society (1997) 13(3/4): 147-149. Cited in Review of Applied Entomology Series A 66: 495 (1978).
Wallner, W.E.; Humble, L.M.; Levin, R.E.; Baranchikov, Y.N.; Cardé, R.T. 1995. Response of adult lymantriid moths to illumination devices in the Russian Far East. Journal of Economic Entomology 88(2): 337-342.
Zlotina, M. A.; Mastro, V.C.; Leonard, D.E.; Elkinton, J.S. 1998. Survival and development of Lymantria mathura (Lepidoptera: Lymantriidae) on North American, Asian and European tree species. Journal of Economic Entomology 91(5): 1162-1166.
Zlotina, M.A.; Mastro, V.C.; Elkinton, J.S.; Leonard, D.E. 1999. Dispersal tendencies of neonate larvae of Lymantria mathura and the Asian form of Lymantria dispar (Lepidoptera: Lymantriidae). Environmental Entomology 28(2): 240-245.
 
AUTHOR(s)
Name(s):
Judy Rosovsky
 
 
Name and Address of the First Author:
Judy Rosovsky
Vermont Monitoring Cooperative
111 West St.
Essex Junction, VT
USA 05452
 
CREATION DATE:        03/11/01
MODIFICATION DATE:       

    
Selected images from Forestry Images (www.forestryimages.org)
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1277089
1277089

Adult(s)
Male, Hong Kong
Photo by David Mohn,


1277093
1277093

Adult(s)
Female. Hong Kong
Photo by David Mohn,



1277083
1277083

Pupa(e)
Hong Kong
Photo by David Mohn,


1277076
1277076

Larva(e)
Hong Kong
Photo by David Mohn,



1277070
1277070

Larva(e)
Second instar, Hong Kong
Photo by David Mohn,


1277064
1277064

Egg(s)
Hong Kong
Photo by David Mohn,