Retithrips syriacus (Mayet)
Taxonomic placing: Insecta, Hemimetabola, Thysanoptera, Terebrantia, Thripidae.
Common name: Black vine thrips.
Geographical distribution: The Middle East, Africa, India, North and Central America.
Host plants: Over 50 hosts, including avocado, grape, mango, pecan, walnut and many ornamentals.
Morphology: The adult is 1.3-1.5 mm long, dark red, the feather-like wings are pale brown. The nymphs are initially hyaline, later turning yellow-orange, and then red; length up to 1.5 mm.
Life cycle: Females insert their eggs (about 50/female) into leaves, and the emerging young feed immediately. The adults also feed, usually on the lower side of leaves. A complete life cycle can take about 15-30 days in the field, less in greenhouses. Adults live for more than one month, producing several annual generations.
Economic importance: The feeding of thrips nymphs and adults results in grey markings on the leaves, accompanied by shiny black dots, which are the insects’ excrement. Heavy infestations cause leaf wilt and drop. Attacked fruits may fail to develop normally. The market value of contaminated roses can drop due to the damaged leaves.
Management
Monitoring: The invasions of the black vine thrips often begin at the borders of orchards, thus periodical leaf examinations of the relevant trees for the easily-seen red pest can serve as monitoring.
Chemical control: The pest can readily be controlled with Sabadilla, a botanical pesticide produced from seeds of Schoenocaulon officinale (Schltdl. & Cham.) A.Gray (Liliaceae) and by Timor C, a product based on the extracts of several plants.
Biological control: The larval parasitoid Ceranisus menes and the egg parasitoid Megaphragma priesneri are common enemies of R. syriacus. Predators include the thrips Franklinothrips megalops Trybom and several phytoseiid mites, but their overall effect is not clear.
References
Ben-Yakir, D. 2012. The black vine thrips Retithrips syriacus (Mayet) as a pest of fruit trees and grape vine. Alon HaNotea 66 (11): 40-41 (in Hebrew with an English abstract).
lzhar, Y., Ben-Yehuda, S., Swirski, E., Wysoki, M., and Dagan, M., 1992. Occurrence of the black vine thrips, Retithrips syriacus Mayet, on avocado in Israel and trials in controlling the pest by insecticides of plant origin. Alon HaNotea 46: 523-529 (in Hebrew, with an English abstract).
Kotzer, Y., Dagan, D., Vardi, Y., and Reuveni, H. 2009. Timor C – an organic compound to control the black vine thrips in persimmon. Alon HaNotea 63 (12): 39-41 (in Hebrew with an English abstract).
Kuslitzky, W. 2003. New variant: Annotated list of hymenopterous parasitoids of thrips in Israel. Phytoparasitica 31 (3).
Mound, L. 2007. Black vine thrips (Retithrips syriacus) pest and diseases image library. At website http: www.padil.gov.au simplePestSearchResults.aspx? fldKeywords=retithrips%20syriacus.