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Stenchaetothrips biformis
Fig. 1


Fig. 2


Fig. 3


Fig. 4


Fig. 5


Fig. 6

Tergites 4-6

Fig. 7

Sternites 4-6

Fig. 8

Tergites 8-9


Fig. 1: Antenna (inset: III. and IV. antennal segment)
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Forewing
Fig. 6: Tergites IV - VI
Fig. 7: Sternites IV - VI
Fig. 8: Tergites VIII and IX

Taxonomic Information

Stenchaetothrips biformis (Bagnall, 1913)

Chloethrips blandus zur Strassen, 1975 
Thrips dobrogensis Knechtel, 1964 
Plesiothrips o Girault, 1929 
Thrips holorphnus Karny, 1925 
Thrips(Bagnallia) oryzae Williams, 1916
Bagnallia adusta Bagnall, 1913 
Bagnallia biformis Bagnall, 1913 
Bagnallia melanurus Bagnall, 1913 

Common name:
Oriental rice thrips

Present taxonomic position:
Family: Thripidae Stephens, 1829
Subfamily: Thripinae (Stephens) Karny, 1921
Gebus: Stenchaetothrips Bagnall, 1926


Species Recognition

General information about the genus Stenchaetothrips:
This genus is thought to be closely related to the genus Thrips and has the common character of paired ctenidia on the lateral sides of the abdominal tergites V through VIII. In addition, the antennae are seven segmented, and segments III and IV have forked sense cones. The 24 species that are included in this genus are associated with grasses and we include S. biformis the ‘rice thrips’ in this key.

Typical character states of Stenchaetothrips biformis:

Body color
Mainly brown

Number of antennal segments: 7
Segment IV - forked sensorium: scarcely extending beyond base of segment V
Segments II and III shape: more or less symmetric
Segments III & IV sensoria: emergent and forked
Base of sensorium on antennal segment VI: no more than 2 times as wide as base of nearest seta
Terminal antennal segments: rarely elongate

Distance between bases of ocellar setae III: greater than width of first ocellus
Head shape between compound eyes: not prolonged
Ocellar setae III on head: arising on anterior margin of, or in front of, ocellar triangle
Postocular setae I: absent
Surface of head, pronotum and fore legs: without strong reticulate sculpture
Ocellar setae I in front of anterior ocellus: absent

Number of pairs of elongate pronotal setae: 0-3
Number of pairs of elongate posteroangular pronotal setae: 2
Pronotum shape: rectangular
Number of pairs of pronotum posteromarginal minor setae: 3
Length of anteromarginal median seta: S1 longer than S2

Mesothoracic endofurca: without median spinula

Metanotal median area sculptured lines: transverse at anterior, but longitudinal and parallel on posterior half
Metanotal median setae position: arising behind anterior margin
Metanotum: with campaniform sensilla
Metanotum major sclerite: with two major sclerites, metascutum and metascutellum
Metanotum median area: with no equiangular reticulation
Metanotum sculpture: without dominant sculptured triangle medially
Metathoracic endofurca: transverse, sometimes with simple median spinula

Wings: present and more than half as long as abdomen
First vein of forewing: distinct from costal vein
Forewing anterior margin: with setae and cilia but cilia longer than setae
Forewing color: uniformly light brown
Forewing costal fringe of cilia: arising at anterior margin of wing
Forewing costal setae at middle of wing: shorter than median width of wing
Forewing first vein setal row: incomplete, with setae not closely and uniformly spaced
Forewing posterior margin cilia: undulated near apex
Forewing second vein setal row: complete, with setae closely and uniformly spaced
Forewing surface: not reticulate
Forewings: with veins, setae and microtrichia

Fore tibial apex: not extending around fore tarsus
Mid and hind tarsi: with two segments

Abdominal pleurotergites:  not covered in microtrichia
Abdominal segment X: never tubular, longitudinally incomplete ventrally in both sexes
Abdominal sternite III of female: without glandular areas
Abdominal sternite VII: with marginal setae but no discal setae
Abdominal sternite VII median marginal setae: arising in front of margin
Abdominal sternites IV , V and VI: with marginal setae but no discal setae
Number of lateral marginal setae on abdominal tergite II: 4
Abdominal tergites: without curved wing-retaining setae
Abdominal tergites IV & V median setal pair: much shorter than distance between their bases
Abdominal tergites V-VII: with pair of ctenidia laterally
Setae on abdominal tergite X: slender
Surface of lateral thirds of abdominal tergites: without regular rows of fine microtrichia
Ctenidia on tergite VIII: posteromesad to spiracle
Tergite VIII posteromarginal comb of microtrichia: present, complete medially
Tergite VIII posteromarginal microtrichia: long, slender and regular or irregular



Life history:
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle can take about 15 days (Lewis, 1973) to over a month and adults may live for more than one month producing several generations in one year depending on seasonal weather.

Host plants:
Rice, grasses 

Vector capacity:
None identified

Current known distribution:
Africa, Central and South America, Europe

Additional notes:
This species is a pest of rice and other grasses and damages the sheath by feeding and laying eggs. The larvae develop and feed on developing leaves.


Lewis, T (1973): Thrips their biology, ecology and economic importance. Academic Press Inc., London Ltd. 349 pp.
Madhusudhan, VV & Gopalan, M (1989): Studies on the biology of rice thrips, Stenchaetothrips biformis (Bagnall) in India. - Tropical Pest Management 35 (4): 394-396.
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 microscopial methods. CBIT, University of Queensland,CDROM ISBN 1-86499-781-8.
Mound, LA & Kibby, G (1998): Thysanoptera: An identification guide,  (2nd edition). CAB International, Wallingford and New York, 70pp.
Mound, LA & Marullo, R (1996): The thrips of Central and South America: An Introduction (Insecta: Thysanoptera). Associated Publishers, Gainesville.
Nugaliyadde, L & Heinrichs, EA (1984):Biology of rice thrips, Stenchaetothrips biformis (Bagnall) (Thysanoptera, Thripidae) and a greenhouse rearing technique. - Journal of Economic Entomology 77 (5): 1171-1175.
Nugaliyadde, L & Heinrichs, EA (1984): Resistance of Oryza Spp to thrips, Stenchaetothrips biformis (Bagnall) (Thysanoptera, Thripidae). - Crop Protection 3 (3): 305-313.
Velusamy, R (1990): Relative susceptibility of high-yielding rice varieties to the thrips, Stenchaetothrips biformis (Bagnall) (Thysanoptera, Thripidae). - Crop Protection 9 (3): 193-196.
Velusamy, R & Saxena, RC (1991): Genetic evaluation for resistance to rice thrips (Thysanoptera, Thripidae) in leafhopper-resistant and planthopper-eesistant eice varieties. - Journal of Economic Entomology 84 (2): 664-668.

Mound, LA (2005): Thysanoptera (Thrips) of the World - A Checklist. http://www.ento.csiro.au/thysanoptera/worldthrips.html