Dendrothripoides innoxius (Karny, 1914)

Thripinae, Thripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: 8-segmented antenna, segments III and IV with forked sense cone, terminal segments VI-VIII
Fig. 2: Head dorsal with ocellar triangle, scape and pedicel
Fig. 3: Head dorsal with ocellar triangle
Fig. 4: Pronotum
Fig. 5: Meso- and metanotum
Fig. 6: Fore wing and base of fore wing
Fig. 7: Tergites V-VII
Fig. 8: Tergites VIII-XI

Dendrothripoides innoxius breeds on leaves of several species of Ipomoea, including cultivated sweet potato and Chinese water spinach. Female macropterous or micropterous (with wing lobe shorter than thorax width); body color golden yellow, with brown shadings laterally; antennal segments IV & VI brown in apical half or more, segments VII & VIII brown; fore wings pale with brown marking sub-basally and more extensively medially (about one-fourth to one-third in length). Antennae 8-segmented; segments III & IV with slender forked sense cone, VIII at most 1.5 times as long as VII (Fig. 1). Head with cheeks bulging behind eyes but constricted to basal neck; dorsal surface reticulate; with 2 pairs of ocellar setae, pair I absent, pair III on anterior margins of ocellar triangle (Fig. 2 and 3). Pronotum with discal setal bases prominent and without long setae; single posteroangular setae short and as long as discal setae (Fig. 4). Meso- and metafurca without spinula. Metanotum irregularly reticulate; median setae arise well behind anterior margin; campaniform sensilla present (Fig. 5). Mid and hind tarsi 2-segmented. Fore wing unusually slender; veinal setae minute (Fig. 6). Tergites II-VIII with numerous irregular arranged, stout and large microtrichia laterally; VI-VIII with 1 or 2 pairs of stout setae medially pointing toward midline (Fig. 7); IX & X with setae stout; X fully divided medially. Sternites without sculpture; median pair of setae on VII arising at margin (Fig. 8).
Male micropterous and similar to female; tergite IX with pair of stout thorn-like setae arising from a large median tubercle, posterior to this a group of 6 small tubercles; antecostal ridge of sternites IV-VII with small transverse glandular area.

The genus Dendrothripoides Bagnall, 1923
There are 5 known species included in this genus, one is from Southern Africa, three from Asia and the fifth, Dendrothripoides innoxius, is widespread around the world on Ipomoea leaves (Mound & Marullo 1996). The species in this genus have unique numerous stout tooth-like michrotrichia on the lateral thirds of the tergites, the fore wings are unusually slender, and the pronotum has a single pair of posteroangular setae.

Compared to Dendrothripoides venustus, Dendrothripoides innoxius has no elongate posteroangular pronotal setae (a single posteroangular seta is short and as long as discal setae), antennal segment VIII is at most 1.5 times as long as VII, fore wings are pale with brown markings sub-basally and more extensive medially (median dark band about one-fourth to one-third in length), and tergites VI & VII bear 1 or 2 pairs of stout setae medially pointing toward midline. Dendrothripoides venustus with 1 pair of elongate posteroangular pronotal setae which are twice the length of discal setae, antennal segment VIII is about twice as long as VII, the median dark area of fore wings are broad and about two-thirds in length, and tergites VI & VII bear a median pair of small and straight setae.
Species of Dendrothripoides are similar to species of Scirtothrips, Kenyattathrips katarinae, Neohydatothrips samayunkur and Hydatothrips adolfifriderici in having the surface of lateral thirds of tergites bearing numerous microtrichia, but only in the genus Dendrothripoides these microtrichia are irregular, stout and teeth-like. In other species the microtrichia are fine and normally arranged in regular rows.

Life history
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle can take less than one week to over a month and adults may live for more than one month producing several generations in one year depending on seasonal weather (Lewis 1973).

Host plants
Ipomoea (sweet potato, Ipomoea batalas, and chinese water spinach, Ipomoea aquatica).

Vector capacity
None identified, but possible mechanical distribution of phytopathogenic fungi and bacteria.

Damage and symptoms
-

Detection and control strategies
-

Additional notes
-

Biogeography

Oriental region, Pacific region, French Polynesia, India, Indonesia, Brazil, Panama, Carribean Islands, Australia. Nigeria.

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Girault AA (1933). Some beauties inhabitant not of commercial boudoirs but of nature's bosom, notably new insects. Published privately, Brisbane, 5 pp

Karny H (1914). Beiträge zur Kenntnis der Gallen von Java. Zweite Mitteilung über die javanischen Thysanopterocecidien und deren Bewohner. Zeitschrift für Wissenschaftliche Insektenbiologie. 10: 355-369

Karny H (1925). Die an Tabak auf Java und Sumatra angetroffenen Blasenfüsser. Bulletin van het deli Proefstation te Medan. 23: 1-55

Karny H (1926). Studies on Indian Thysanoptera. Memoirs of the Department of Agriculture in India, Entomological Series. 9 (6): 187-239

Kudo I (1977). The genus Dendrothripoides Bagnall (Thysanoptera, Thripidae). Japanese Journal of Entomology (Konchū). 45 (4): 495-500

Lewis T (1973). Thrips: their biology, ecology and economic importance. Academic Press Inc., London Ltd., 349 pp

Moritz G (2006). Thripse. Pflanzensaftsaugende Insekten, Bd. 1, (1. Auflage). Westarp, Hohenwarsleben, 384 pp. ISBN-13: 978 3 89432 891 7

Moritz G, Morris DC & Mound LA (2001). ThripsID - Pest thrips of the world. ACIAR and CSIRO Publishing Collingwood, Victoria, Australia, CDROM ISBN 1 86320 296 X

Moritz G, Mound LA, Morris DC & Goldarazena A (2004). Pest thrips of the world - an identification and information system using molecular and microscopical methods. Centre for Biological Information Technology, University of Queensland, Australia, CDROM ISBN 1 86499 781 8

Moritz G, O'Donnell C & Parrella M (2009). Pest thrips of North America. Centre for Biological Information Technology, University of Queensland, Australia, CDROM ISBN-13: 978 1 86499 940 2

Mound LA & Marullo R (1996). The Thrips of Central and South America: An introduction (Insecta: Thysanoptera). Memoirs on Entomology, International, Vol. 6. Associated Publishers, Gainesville, 487 pp

Nickle DA (2003). A checklist of commonly intercepted thrips (Thysanoptera) from Europe, the Mediterranean, and Africa at U.S. ports-of-entry (1983-1999). Part 1. Key to genera. Proceedings of the Entomological Society of Washington. 105 (1): 80-99