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Gladiolus Thrips, Thrips simplex (Morison) (Insecta: Thysanoptera: Thripidae)1
H. A. Denmark and J. F. Price2
Introduction
The gladiolus thrips causes deformities and discoloration of gladiolus flowers, and corms (bulbs) become soft and are prone to decay.
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Figure 1. Adult female gladiolus thrips, Thrips simplex (Morison). Synonymy
The gladiolus thrips was described by Morison (1930) as Physothrips simplex from five female specimens collected on carnation flowers, Dianthus caryophyllus, from Urrbrae, South Australia. The holotype and one paratype are deposited in the British Museum.Moulton and Steinweden (1931) described this thrip under the name Taeniothrips gladioli from Ontario, Canada, and it was synonymized by Steele (1935). Bhatti (1969) placed gladioli in the genus Thrips. Kellie O'Neill of the U.S. National Museum (retired) has suggested that this thrips probably originated in Africa as did its preferred host, gladiolus, Gladiolu x hortulanus.
Distribution
Gladiolus thrips is widespread and is found where gladiolus are grown in Africa, Asia, Australia, the Pacific Islands, Europe, and North and South America. It is found in almost all states in the United States. Although it cannot overwinter out-of-doors in northern Europe and northern North America, the spread of this thrips probably results from its infested corms being shipped to all parts of the country. It was first found in Florida in 1932 (Watson 1941).Description
Adults emerge milky-white, but soon turn brown and begin feeding. The female is approximately 1.65 mm long and slightly larger than the male. The antennae are dark brown except for the 3rd segment which is light brown. The wings have a light tranverse band near the base. The egg is about 0.3 mm long, opaque white, smooth, and bean-shaped. Eggs are deposited in the leave tissue and corms. The two larval stages are light yellow and are usually found beneath the leaves or bracts. The fully developed 2nd instar larva is about the size of the adult. The 1st pupal stage is distinguished from the 2nd pupal stage by having forward projecting antennae and short wing pads. The 2nd pupal stage, which is a quiescent period, has the antennae folded over the back and much longer wing pads.
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Figure 2. From left to right: egg and first larval stage, second larval stage, first pupal stage, second pupal stage.
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Figure 3. Head and prothorax of the gladiolus thrips, Thrips simplex (Morison), showing setae. Host Plants
The thrips feed and reproduce primarily on gladiolus flower spikes and corms; however, it has been recorded from Philodendron selloum, Clitoria sp., Rhododendron indicum, Calendula, and crow-foot grass, Eleusine indica. This thrips has never been reared from these plants and they cannot be considered valid hosts. It was reported to reproduce on Tritonia sp., Tigridia sp., and Kniphofia sp.
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Figure 4. Flower damage caused by feeding of the gladiolus thrips, Thrips simplex (Morison).
CREDITS: Division of Plant Industry
Figure 5. Gladiolus bloom damage (on right), produced by gladiolus thrips, Thrips simplex (Morison), feeding.
CREDITS: Division of Plant Industry
Figure 6. Gladiolus corm on right showing advanced stage of injury by gladiolus thrips, Thrips simplex (Morison). Management
Several insecticides can be used to suppress gladiolus thrips.
For more information please see:
Insect and Mite Management Guide for Gladiolus (http://edis.ifas.ufl.edu/IG005 ).Selected References
Bhatti, J.S. 1969. Taxonomic studies in some Thripini (ThysanopteraThripidae). Oriental Insects 3:373-382.Funderburk J, Stavisky J, Olson S, Momol T. (2000). Thrips biology and management. http://thrips.ifas.ufl.edu/Background.htm (18 August 2004).
Magie, R.O., A.J. Overman, J.P. Gilbreath, W. E. Waters, G..J. Wilfret, J.F. Price, and S.S. Woltz. 1988. Gladiolus corm production. Gladio Grams Bulletin No. 69 2-28.
Mizell, R.F., T.R. Fasulo, and D.E. Short. 2002. WoodyBug pest and beneficial arthropods of southeastern U.S. woody ornamentals . University of Florida/IFAS. CD-ROM. SW 119.
Morison, Guy D. 1930. On a collection of Thysanoptera from South Australia. Bulletin of Entomological Research 21 9-14.
Moulton, Dudley and John B. Steinweden. 1931. A new Taeniothrips on gladiolus. Canadian Entomologist 43 20-21.
Steele, H. Vevers. 1935. Thrips investigation Some common Thysanoptera in Australia. Council for Scientific and Industrial Research, Commonwealth of Australia, Pamphlet 54. 59 p.
Watson, J.W. 1941. The gladiolus thrips in Florida. University of Florida Agricultural Experiment Station Bulletin 357. 23 p.
Footnotes
1. This document is EENY-036 (IN163) (originally published at DPI Entomology Circular 322), 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: June, 1998. Revised: January 2007. This document is also available on Featured Creatures Website at http://creatures.ifas.ufl.edu. Please visit the EDIS Website at http://edis.ifas.ufl.edu.2. H. A. Denmark and J. F. Price, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.
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. Larry Arrington, Dean.
Copyright Information
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