Tomato Leaf Miner | Liriomyza bryoniae (Kaltenbach)

Tomato Leaf Miner (Liriomyza bryoniae)
W. Billen, Pflanzenbeschaustelle, Weil am Rhein,
California Pest Rating for
Tomato leaf miner | Liriomyza bryoniae (Kaltenbach)
Diptera: Agromyzidae
Pest Rating: A



Initiating Event:

Liriomyza bryoniae is currently Q-rated.  A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background:  Adult Liriomyza bryoniae are small (approximately 2 mm in length) flies that are yellow, brown, and black in color. (Spencer, 1973).  This fly is a pest in field crops and in greenhouses.  An unusually broad range (for an agromyzid) of plant families are attacked, including Apiaceae, Asteraceae, Brassicaceae, Capparaceae, Caryophyllaceae, Chenopodaceae, Cucurbitaceae, Fabaceae, Malvaceae, and Solanaceae, among others (Spencer, 1990).  Economically-significant host plants include tomato, cucumber, melons, beans, parsley, coriander, lettuce, squash, spinach, peppers, petunias, and chrysanthemum (Elkhouly et al., 2015; Masetti et al., 2004; Minkenberg and Van Lenteren, 1986; Shiao, 2004; Tran, 2009; Van Der Linden, 1993).  Reproductive potential is high.  Individual females have been reported to lay up to 183 eggs (Tokumaru and Abe, 2003). The eggs are laid in leaves that then serve as food for the larvae.   The larvae are legless and cream to yellow-orange in color, and tunnel or “mine” between the upper and lower epidermal layers of the leaf. The mines are not associated with the leaf veins (as in some other agromyzid species), except sometimes the midrib, and sometimes form secondary blotch mines.  The larvae exit the leaf to pupate, presumably in soil like most Liriomyza species (Collins and Anderson, 2016; Pitkin et al., 2017; Spencer, 1973).  Larval feeding damage can kill the leaves and sometimes the entire plant, especially if it is young (Spencer, 1973).  Some Liriomyza species are known to vector plant viruses, although it is not known if L. bryoniae does (Zitter and Tsai, 2013), and some agromyzids are known to vector plant pathogenic fungi (Mathew et al., 2015).

Worldwide Distribution:  Liriomyza bryoniae is widely distributed and present from Europe and northern Africa east to East Asia.  It is apparently native to southern Europe; the other areas it is found in (including northern Europe, where it is found mainly in greenhouses) are presumed to represent introductions (CABI, 2018; Minkenberg and Van Lenteren, 1986; Spencer, 1973).

Official Control: Liriomyza bryoniae is listed as a high priority pest in Australia and it is considered Reportable by the USDA-APHIS.

California Distribution:  Liriomyza bryoniae is not known to be present in California (Symbiota Collections of Arthropods Network).

California Interceptions:  Liriomyza bryoniae may have been intercepted on Polemonium sp. from Washington in September, 2002.  This identification was tentative (California Department of Food and Agriculture).

The risk Liriomyza bryoniae would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Liriomyza bryoniae is widely distributed, suggesting it is tolerant of a wide range of conditions. Although it does not tolerate the very cold temperatures found in northern Europe, as shown by its apparent restriction to greenhouses there, it has been shown to successfully overwinter and survive frost in the Netherlands (Van der Linden, 1993).  It seems likely that the climate of a large portion of California would be suitable for this fly.  This species is highly polyphagous, and known host plants occur over much of the state.  Therefore, Liriomyza bryoniae receives a High (3) in this category.

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Liriomyza bryoniae is highly polyphagous and has been reported to feed on plants in at least 16 families. Therefore, it receives a High (3) in this category.

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Reproductive and Dispersal Potential: Liriomyza bryoniae, like other agromyzids is a strong flier, and the larvae could possibly be moved with infested plant material. The species has high reproductive potential, with individual females laying up to 183 eggs each. Therefore, it receives a High (3) in this category.

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Feeding by larvae of Liriomyza bryoniae impacts numerous vegetable crops, including tomato, peppers and cucumber.  This damage could lower crop yield and increase production costs.  The presence of this species in crop fields could trigger the loss of markets.  Therefore, it receives a High (3) in this category.

Economic Impact:  A, B, C

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 3

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

– High (3) causes 3 or more of these impacts.

5) Environmental Impact: Liriomyza bryoniae is a pest of vegetables, including tomato, peppers and cucumber. Infestations of this fly could impact home gardens and trigger treatments.  Therefore, it receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact:  D, E

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

 E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Environmental Impact Score:  3

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Liriomyza bryoniae: High (15)

Add up the total score and include it here.

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: Liriomyza bryoniae is not known to be present in California.  It receives a Not established (0) in this category.

–Not established (0) Pest never detected in California, or known only from incursions.

–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: High (15)


The most significant uncertainty in this proposal is the potential for Liriomyza bryoniae to significantly impact crop plants.  Although death of seedlings is reported to occur, little quantitative information was found regarding the damage inflicted by this fly.  It is possible that this fly would have a more significant impact in California than it does in the Old World, because it is presumably somewhat controlled by natural enemies that are present in Europe but not in California.

Conclusion and Rating Justification:

Liriomyza bryoniae is a polyphagous pest of vegetables and horticultural plants in fields and greenhouses.  It is not known to be present in California.  For these reasons, an “A” rating is justified.


Benker, U.  2012.  Monochamus alternatus – The next alien causing trouble.  Forstschutz Aktuell 55:34-37.

CABI.  2018.  Liriomyza bryoniae.  CAB International.  Accessed May 23, 2018:

California Department of Food and Agriculture.  2018.  Pest and damage record database.  Accessed April 18, 2018:

Collins, D. and Anderson, H.  2016.  Liriomyza species – leaf mining flies.  Plant Pest Factsheet.  Department for Environment Food & Rural Affairs.

Elkhouly, A. R., Albasha, M. O., and Hririg, A. L.  2015.  Population abundance of the ectoparasitoid Diglyphus isaea Walker (Hymenoptera: Eulophidae) on tomato leaf miner Liriomyza bryonia. (Kaltenbach) (Diptera: Agromyzidae) on some winter host plants in Alejelat Region, Libya.  Journal of Agricultural Engineering and Biotechnology 3:41-45.

Masetti, A., Lanzoni, A., Burgio, G., and Süss, L.  2004.  Faunistic Study of the Agromyzidae (Diptera) on weeds of marginal areas in northern Italy agroecosystems.  Annals of the Entomological Society of America 97:1252-1262.

Mathew, F. M., Prasifka, J. R., Gaimari, S. D., Shi, L., Markell, S. G. and Gulya, T. J. 2015. Rhizopus oryzae associated with Melanagromyza splendida and stem disease of sunflowers (Helianthus annuus) in California. Plant Health Progress 16:39–42.

Minkenberg, O. P. J. M. and Van Lenteren, J. C.  1986.  The leafminers Liriomyza bryoniae and L. trifolii (Diptera: Agromyzidae), their parasites and host plants: A review.  Agricultural University Wageningen Papers 86-2:1-50.

Pitkin, B., Ellis, W., Plant, C., and Edmunds, R.  2017.    Liriomyza bryoniae (Kaltenbach, 1858).  The leaf and stem mines of British flies and other insects.  Accessed May 15, 2018:

Shiao, S. -F.  2004.  Morphological diagnosis of six Liriomyza species (Diptera: Agromyzidae) of quarantine importance in Taiwan.  Applied Entomology and Zoology 39:27-39.

Spencer, K.A.  1973.  Agromyzidae (Diptera) of Economic Importance.  Springer.

Spencer, K.A. 1990. Host Specialization in the World Agromyzidae (Diptera). Kluwer Academic Publishers, Dordrecht, Netherlands.

Symbiota Collections of Arthropods Network.  Accessed May 18, 2018:

Tokumaru, S., and Abe, Y. 2003. Effects of temperature and photoperiod on development and reproductive potential of Liriomyza sativae, L. trifolii, and L. bryoniae (Diptera: Agromyzidae). Japanese Journal of Applied Entomology and Zoology 47:143-152.

Tran, D. H.  2009.  Agromyzid leafminers and their parasitoids on vegetables in central Vietnam.  Journal of the International Society for Southeast Asian Agricultural Sciences 15:21-33.

Van der Linden, A.  1993.  Overwintering of Liriomyza bryoniae and Liriomyza huidobrensis (Diptera: Agromyzidae) in the Netherlands.  Proceedings of the section Experimental and Applied Entomology of the Netherlands Entomological Society 4:145-150.

Zitter, T. A. and Tsai, J. H.  2013.  Flies.  pp. 165-176 in K.F. Harris and K. Maramorosch (eds.), Vectors of Plant Pathogens.  Academic Press, New York, NY.


Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741;[@]

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211,[@]

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7/24/18 – 9/07/18


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Pest Rating: A


Posted by ls