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Publication #EENY073

 

Blotch Leafminer,Amauromyza maculosa(Malloch) (Insecta: Diptera: Agromyzidae)1

H. V. Weems, Jr. and G. W. Dekle2

Introduction

A blotch leafminer, Amauromyza maculosa (Malloch), is a pest of dooryard plantings of chrysanthemum throughout most of Florida. It is not an important pest of commercial chrysanthemums in the principal commercial planting areas of Bradenton-Ft. Myers and Stuart-Delray Beach. This species, which, according to Spencer and Stegmaier (1973), probably evolved in South America and has extended its range into North America since the end of the Pleistocene Period, may be distinguished readily from related species by the variegated color of the halteres of the adult flies. The large blotch mines, produced on foliage by the feeding of the larvae, are similar to those produced by larvae of another agromyzid fly, Nemorimyza posticata (Meigen), which also occurs in Florida and usually on Solidago and Aster.

Figure 1. 

Foliar damage caused by the blotch leafminer, Amauromyza maculosa (Malloch), showing leaf with mines and oviposition punctures.


Credit: Division of Plant Industry
[Click thumbnail to enlarge.]

Synonymy

Agromyza maculosa Malloch, 1913: 302. Holotype female from Jamaica, New York, in U.S. National Museum of Natural History.

Phytobia (Amauromyza) maculosa Frick, 1952: 393.

Distribution

Throughout most of the United States, including Florida and Hawaii; Antilles, Bahamas, Bermuda, Costa Rica, Argentina, Brazil, Uruguay and Venezuela.

Identification

The adult is a small, shiny black, clear-winged fly about 2.2 to 2.7 mm long. Head entirely black; mesonotum shining black; pleura and legs entirely black; squamae and fringe silvery white; halteres variegated, primarily white, but knob with a conspicuous black area above; wing length about 2.2 to 2.7 mm. Larvae are yellowish white, about 3 mm long, and make blotch-like tunnels within leaves where these larvae are readily visible as they feed.

Figure 2. 

Adult female blotch leafminer, Amauromyza maculosa (Malloch), ovipositing in a chrysanthemum leaf.


Credit: Division of Plant Industry
[Click thumbnail to enlarge.]

Figure 3. 

Mature larva of the blotch leafminer, Amauromyza maculosa (Malloch).


Credit: Division of Plant Industry
[Click thumbnail to enlarge.]

Hosts

Polyphagous on Compositae; known hosts in Florida include Baccharis, Bidens, Chrysanthemum, Emilia, Erechtites, Eupatorium, Gaillardia, Gnaphalium, Helianthus, Melanthera, Senecio, Sonchus, and Tagetes. Recorded hosts elsewhere include Arctium, Artemisia, Aster, Erigeron, Lactuca, and Xanthium.

Leaf Damage

Feeding larvae cause conspicuous blotch mines in foliage before they emerge and pupate externally. Injury to foliage by mines and oviposition punctures causes plant to be unsightly. Heavy infestations may cause some leaf mortality. Three to six larvae are common in a single leaf, frequently forming a large community mine.

Figure 4. 

Chrysanthemum plant severely infested by the blotch leafminer, Amauromyza maculosa (Malloch).


Credit: Division of Plant Industry
[Click thumbnail to enlarge.]

Figure 5. 

Blotch mine in chrysanthemum leaf opened to expose the feeding larva of the blotch leafminer, Amauromyza maculosa (Malloch).


Credit: Division of Plant Industry
[Click thumbnail to enlarge.]

Figure 6. 

Oviposition punctures in chrysanthemum leaf caused by the blotch leafminer, Amauromyza maculosa (Malloch).


Credit: Division of Plant Industry
[Click thumbnail to enlarge.]

Management

Pest management programs for commercial production of chrysanthemums are sufficient to control A. maculosa.

For additional information see the Insect Management Guide for Landscape Plants (http://edis.ifas.ufl.edu/IG013).

Selected References

Frick, K.E. 1952. A generic revision of the family Agromyzidae (Diptera) with a catalogue of New World species. California University Publication Entomological 8: 339-452.

Frick, K.E. 1959. Synopsis of the species of agromyzid leafminers described from North America (Diptera). U.S. Natural History Museum 108: 347-465.

Frost, S.W. 1924. A study of the leaf-mining Diptera of North America. New York (Cornell) Agricultural Experiment Station 78: 1-228.

Malloch, J.R. 1913. A revision of the species in Agromyza Fallén, and Cerodontha Rondani (Diptera). Annals of the Entomological Society of America 6: 269-336.

Mizell, R.F., D.E. Short and T.R.Fasulo. (May 1998). WoodyPest. UF/IFAS. http://entomology.ifas.ufl.edu/fasulo/woodypest (January 29, 2010).

Spencer, K.A., and C.E. Stegmaier, Jr. 1973. Agromyzidae of Florida with a supplement of species from the Caribbean. Arthropods of Florida and neighboring land areas 7: 1-205.

Stegmaier, C.E., Jr. 1967. Some new host plant records and parasites of Phytobia (Amauromyza) maculosa in Florida (Diptera: Agromyzidae). Florida Entomologist 50: 99-101.

Stone, Alan, et al. 1965. A catalogue of the Diptera of America north of Mexico. USDA Agricultural Handbook No. 276. 1696 p.

Waters, W.E., and C.A. Conover. 1969. Chrysanthemum production in Florida. University of Florida Agricultural Experiment Station Bulletin 730: 1-64.

Footnotes

1.

This document is EENY-073 (originally published as DPI Entomology Circular No. 132), 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: February 1999. Reviewed: March 2011. 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.

H.V. Weems, Jr., and G.W. Dekle, Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, FL.

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 extension publications, contact your county Cooperative Extension service.

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