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Liriomyza brassicae (Riley)

Serpentine Leafminer
Hosts Distribution Damage Biology Behavior Management Reference


Ronald F.L. Mau, Extension Entomologist

Jayma L. Martin Kessing, Educational Specialist

Department of Entomology

Honolulu, Hawaii

Updated by: J.M. Diez April 2007


Food hosts comprise of cultivated and wild plants in the family Cruciferae. In Hawaii it is considered a serious pest on broccoli, cabbage, cauliflower, Chinese broccoli, flowering white cabbage and other cruciferous crops (Spencer, 1973).


The serpentine leafminer is the most cosmopolitan species known in the Agromyzidae. Although it is not found in Britain and parts of Northern Europe, it has a wide distribution in the Pacific area including Australia, Hawaii, the Orient and Ethiopian regions. In North America it can be found locally in Canada and is abundant in California, Florida and other southern states. It was first recorded on Oahu in 1952 and is now widespread throughout the State.


Larvae feed as leaf-miners on the mesophyll, or middle tissue layer, of the leaf. Mines are linear and irregular, whitish or greenish in color, with occasional thread-like black frass. Individual mines are of little significance, however, entire leaves may be mined when larval populations are large. Injury to mature cabbage plants is usually confined to outer leaves and has no influence on the growth of the plant. In contrast, seedlings may be killed or severely weakened by high larval densities.


The average period of the life cycle of the serpentine leafminer is 21 days, but can be as short as 15 days. The length of the life cycle varies with host and temperature.


Eggs are laid singly in punctures in the leaf epidermis. There is no preference for upper or lower surface. The freshly laid eggs are creamy white and shaped like an elongated oval. The eggs are small, 1/100 inch in length, and hatch 2-4 days.


The maggots are bright yellow to yellow green in color, measuring 1/6 inch in length and 1/50 inch in breadth. There are three larval stages. Each larval instar is completed in 2 - 3 days.


The pupal stage is yellow-brown in color and distinctly segmented. Pupae are rectangular oval shaped narrowing at the ends. This stage does no feeding damage and development is completed in 5 to 12 days.


This adult is a small fly of mat gray with black and yellow splotches and about 1/12 inch of length. Adults live for 10-20 days depending on environmental conditions.


The first larval stage of the serpentine leafminer burrows into the mesophyl tissue. The second stage also feeds in the mesophyl tissue. The third stage larva concentrates its feeding towards the upper leaf surface. When it is mature, it cuts a longitudinal slit in the leaf and leaves to pupate on the leaf surface or on the ground.

Adult emergence generally occurs in the early morning hours before 9:00 a.m.


In Florida, California, Venezuela and Hawaii L. brassicae usually occurs with L. sativae Blanchard (Spencer, 1973).

Infestation is usually heaviest in shady places.


Although not considered a serious pest of crucifers in California and Hawaii.

Parasites of the serpentine leafminer present in Hawaii are Cothonaspis pacifica Yoshimoto, Chrysachares parksi Crawford, and Halticoptera patellana (Dalman).


Cyromazine (Trigard) and abamectin (Avid) are effective against this leafminer pest. Both of the insecticide products have limited crop registrations and must not be used on unregistered crops.

The pest is highly resistant to most other insecticides. Application of ineffective insecticides to control the celery leafminer is futile. It usually results in a larger leafminer problem in the pesticide reduces field densities of leafminer parasites.

There are no listings for Trigard and Avid as of April 2007.


Beri, S. K. 1974. Biology of a Leaf Miner Liriomyza brassicae (Riley) (Diptera: Agromyzidae). J. Nat. Hist. 8(2):143-151.

Hardy, D. E. and M. D. Delfinado. 1980. Genus Liriomyza Mik. pp. 208-211. In Insects of Hawaii. A Manual of the Insects of the Hawaiian Islands, including an Enumeration of the species and Notes on their Origin, Distribution, Hosts, Parasites, etc. Volume 13. Diptera: Cyclorrhapha III, Series Schizophora, Section Acalypterae, Exclusive of Family Diptera. University of Hawaii Press, Honolulu. 451 pages.

Spencer, K. A. 1973. Liriomyza brassicae (Riley, 1884) - Cosmopolitan. pp. 151- 157. In Agromyzidae (Diptera) of Economic Importance. Dr. W. Junk B. V. , Publishers, The Hague.

Waterhouse, D. F. and K. R. Norris. 1987. Liriomyza Species, Diptera: Agromyzidae, Leafminers. pp. 159-176. In Biological Control Pacific Prospects (Ed D.F. Waterhouse & K.R. Norris). Inkata Press, Melbourne. 454 pages.





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