Liriomyza huidobrensis (Blanchard)
Common name: Pea leafminer.
Geographical distribution: A cosmopolitan pest of South American origin that has spread throughout the world due to trade in cut flowers. There are indications that the entity known as Liriomyza huidobrensis is made up of two sibling species, one from North America, the other from South America.
Host plants: Polyphagous, affecting plants in over 20 families
Morphology: Adults are small, less than 2.5 mm in length, mostly black, except for yellow parts of the head. The yellow maggots are about 3 mm in length.
Life history: Females insert their eggs (about 100/female) under the epidermis of the host leaf. The hatched maggots mine within the leaf and at maturity chew a hole in the leaf and drop to pupate on the ground. The females live about 2-3 weeks and have a diel pattern of activity, active at sunrise and again around sunset. The pest prefers cool weather and fails to develop at 30ºC. Its estimated threshold of development is between 7.3 and 8.1ºC. In the hot and dry Middle East the pest is inactive uring most of the summer, active from late autumn to early summer, being very susceptible to severe heat.
Economic importance: The pea leafminer attacks ornamentals and vegetables in open fields, as well as under glass in tropical, subtropical and temperate countries. The larvae mine in the leaves, usually along the midrib and lateral veins, reducing Photosynthetic rates. Overall damage is due to the this reduction and to aesthetic injury from adult feeding wounds on the leaf surfaces. These puncture wounds are made by the females with their ovipositor in order to feed on the expressed plant juices; the wounds result in leaf stippling. The amount of stippling varies with plant species, from about 50 to 300/day. Overall damage affects the commercial value of crops whose leaves are sold as edibles, such as lettuce and spinach, and the aesthetic appearance of ornamentals.
Sampling: Counting live larvae and/or mines, collecting pupae, rearing adults from infested foliage, catching adults with a vacuum sampler and trapping adults on yellow sticky boards.
Horticultural control: Sanitation by removing all harvested plants and adjacent weeds that may serve as reservoirs for the pest. There has been only limited success in using yellow sticky traps, trap plants, and vacuum removal of flies, because the pests quickly reinvade fields.
Chemical control: Adults are relatively resistant to insecticides, and chemical control is directed towards the relatively susceptible early larval stages. Spray decisions should therefore be based only on catches in yellow sticky traps in conjunction with monitoring larval activity. Only translaminar insecticides, like abamectins, neem and spinosad are still effective.
Biological control: A guild of at least 14 hymenopterous parasitoids usually attacks and often controls the pest in the Middle East. Releases of Dacnusa sibirica Telenga, Opius pallipes Wesmael (Braconidae) and Diglyphus isaea Walker (Eulophidae) in greenhouses abroad have been very effective, and D. isaea, along with Neochrysocharis formosa (Westwood) (Eulophidae), are the predominant species in Turkey. Some success has been achieved in using entomopathogenic nematodes for pea leafminer control.
Cıvelek, H.S., Yoldas¸ Z. and Weintraub, P. 2002. The parasitoid complex of Liriomyza huidobrensis in cucumber greenhouses in Izmir Province, Western Turkey. Phytoparasitica 30: 285-287.
Lanzoni, A., Bazzocchi, G.G., Burgio, G. and Fiacconi, M.R. 2002. Comparative life history of Liriomyza trifolii and Liriomyza huidobrensis (Diptera: Agromyzidae) on beans: Effect of temperature on development. Environmental Entomology 31: 797-803.
Maseti, A., Luchetti, A., Mantovani, B. and Burgio, G. 2006. Polymerase chain reaction-restriction fragment length polymorphism assays to distinguish Liriomyza huidobrensis (Diptera: Agromyzidae) from associated species on lettuce cropping systems in Italy. Journal of Economic Entomology 99: 1268-1272.
Parrella, M.P., Jones, V.P., Youngman, R.R. and Lebeck, L.M. 1985. Effect of leaf mining and leaf stippling of Liriomyza spp. on photosynthetic rates of chrysanthemum. Annals of the Entomology Society of America 78: 90-93.
Rauf, A., Shepard, B.M. and Johnson, M.W. 2000. Leafminers in vegetables, ornamental plants and weeds in Indonesia: surveys of host crops, species composition and parasitoids. International Journal of Pest Management 45: 257-266.
Weintraub, P.G. 2001. Changes in the dynamics of the leafminer, Liriomyza huidobrensis, in Israeli potato fields. International Journal of Pest Management 47: 95-102.
Weintraub, P.G. (and 17 co-authors) 2017. The Invasive Liriomyza huidobrensis (Diptera: Agromyzidae): understanding its pest status and management globally. Journal of Insect Science 17: 1-21.
Phyllis G. Weintraub, e-mail: email@example.com Gilat Research Center D.N. Negev, 85280, Israel Telephone: 08 992-6-8678; Fax: 08 992-6485