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Scirtothrips perseae
Fig. 1

Antenna

Fig. 2

Head

Fig. 3

Pronotum

Fig. 4

Pteronotum

Fig. 5

Forewing

Fig. 6

Sternites 5-7

Fig. 7

Tergites 5-7

Fig. 8

Tergites 7-9

Fig. 9

18SMP/28SMP

Figures

Fig.1: Antenna
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Forewing, base of fore wing with alula
Fig. 6: Sternites V - VII
Fig. 7: Tergites V- VII
Fig. 8:Tergites VII - IX

ITS-RFLP gel patterns (1&8 ladder, 2 PCR-product, 3 RSAI, 4 HaeIII, 5 MspI, 6 HinfI, 7 AluI)
Fig. 9: Primer pair 18SMP/28SMP

Taxonomic Information

Species:
Scirtothrips perseae Nakahara, 1997

Common name:
Avocado thrips

Present taxonomic position:
Family: Thripidae Stephens, 1829
Subfamily: Thripinae (Stephens) Karny, 1921
Genus: Scirtothrips Shull, 1909

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Species Recognition

General information about the genus Scirtothrips:
This genus contains about 60 species all having rows of microtrichia on the lateral sides of the tergites and a complete comb on tergite VIII. These are small, pale yellow thrips with eight segmented antennae and segments III and IV have forked sense cones. The pronotum on these thrips is closely and transversely striate and most have spotted areas interrupting the striae. The forewings are narrow with only a few distal setae on the first vein and a few apical setae on the hind vein.

Typical character states of Scirtothrips perseae:

Body color
Mainly pale or yellow,with some darker markings

Antennae
Number of antennal segments: 8
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

Head:
Distance between bases of ocellar setae III:less 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 orarising within ocellar triangle anterior to tangent of anterior margin of hind ocelli
Postocular setae I:present
Surface of head, pronotum and fore legs:without strong reticulate sculpture
Ocellar setae I in front of anterior ocellus: present

Prothorax
Number of pairs of elongate pronotal setae: 0-3
Number of pairs of elongate posteroangular pronotal setae: 1-2
Pronotum shape:rectangular

Mesothorax
Mesothoracic endofurca:with median spinula

Metathorax
Metanotal median area sculptured lines:transverse at anterior, but forming irregular longitudinal reticulations 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
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 brownoruniformly pale or weakly shaded
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:incomplete, with setae not closely and uniformly spaced
Forewing surface:not reticulate
Forewings:with veins, setae and microtrichia

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

Abdomen:
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 at margin
Abdominal sternites IV , V and VI:with marginal setae but no discal setae
Abdominal sternites V & VI microtrichia: restricted to lateral thirds of discal area
Abdominal tergites:without curved wing-retaining setae
Abdominal tergites IV & V median setal pair:longer than distance between their bases
Abdominal tergites V-VII:without paired ctenidia, sometimes with irregular microtrichia
Markings on tergites IV to VI:with shaded areas laterally and antecostal ridges dark
Setae on abdominal tergite X:slender
Surface of lateral thirds of abdominal tergites:with many regular rows of fine microtrichia
Ctenidia on tergite VIII:not present, but groups of microtrichia
Tergite VIII posteromarginal comb of microtrichia:present, complete medially
Tergite VIII posteromarginal microtrichia:long, slender and regular

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Biology

Life history:
The developmental time from egg to adult has been studied in Scirtothrips perseae by Mark Hoddle (2002) who examined the developmental time under several temperatures ranging from 15C to 30C (Hoddle, 2002). In summary the range for development time was 18 to 49 days.

Host plants:
Avocado (Persea americana)

Vector capacity:
None identified

Current known distribution:
Central and South America, North America

Additional notes:
All of the members of this group feed on the leaves of their plant hosts and are quite cryptic in habit. Scirtothrips perseae feeds on the newly developing avocado fruit reducing the fruit from high quality fresh market avocados to processing for guacamole at a significant reduction in crop value in California (Nakahara, 1997).

Bibliography

Bailey, SF (1957): The thrips of California Part I: Suborder Terebrantia. Bulletin of the California Insect Survey 4, no. 5: 143-220.
Bailey, SF (1964): A revision of the genus Scirtothrips Shull (Thysanoptera: Thripidae). Hilgardia 35: 329–362.
Byrne, FJ, Toscano, NC, Urena, AA & Morse, JG (2005): Quantification of imidacloprid toxicity to avocado thrips, Scirtothrips perseae Nakahara (Thysanoptera : Thripidae), using a combined bioassay and ELISA approach. - Pest Management Science 61 (8): 754-758.
Byrne, FJ, Toscano, NC, Urena, AA & Morse, JG (2007): Toxicity of systemic neonicotinoid insecticides to avocado thrips in nursery avocado trees. - Pest Management Science 63 (9): 860-866.
Hoddle, MS (2002):
Developmental and reproductive biology of Scirtothrips perseae (Thysanoptera : Thripidae): a new avocado pest in California. - Bulletin of Entomological Research 92 (4): 279-285.
Hoddle, MS (2002): Oviposition preferences of Scirtothrips perseae Nakahara (Thysanoptera : Thripidae) in southern California avocado orchards. - Pan-Pacific Entomologist 78 (3): 177-183.
Hoddle, MS (2003): The effect of prey species and environmental complexity on the functional response of Franklinothrips orizabensis: a test of the fractal foraging model. - Ecological Entomology 28 (3): 309-318.
Hoddle, MS (2003): Predation behaviors of Franklinothrips orizabensis (Thysanoptera : Aeolothripidae) towards Scirtothrips perseae and Heliothrips haemorrhoidalis (Thysanoptera : Thripidae). - Biological Control 27 (3): 323-328.
Hoddle, MS, Heraty, JM, Rugman-Jones, PF, Mound, LA & Stouthamer, R (2008):Relationships among species of Scirtothrips (Thysanoptera : Thripidae, Thripinae) using molecular and morphological data. - Annals of the Entomological Society of America 101 (3): 491-500.
Hoddle, MS, Jetter, KM & Morse, JG (2003): The economic impact of Scirtothrips perseae Nakahara (Thysanoptera : Thripidae) on California avocado production. - Crop Protection 22 (3): 485-493.
Hoddle, MS, Jones, J, Oishi, K, Morgan, D & Robinson, L (2001): Evaluation of diets for the development and reproduction of Franklinothrips orizabensis (Thysanoptera : Aeolothripidae). - Bulletin of Entomological Research 91 (4): 273-280.
Hoddle, MS, Mound, LA, Rugman-Jones, PF & Stouthamer, R (2008): Synonomy of five Scirtothrips species (Thysanoptera : Thripidae) described from avocados (Persea americana) in Mexico. - Florida Entomologist 91 (1): 16-21.
Hoddle, MS, Nakahara, S & Phillips, PA (2002): Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera : Thripidae) and associated natural enemies on avocado (Persea americana Miller). - Biological Control 24 (3): 251-265.
Hoddle, MS, Oevering, P, Phillips, PA & Faber, BA (2004): Evaluation of augmentative releases of Franklinothrips orizabensis for control of Scirtothrips perseae in California avocado orchards. - Biological Control 30 (2): 456-465.
Hoddle, MS & Robinson, L (2004): Evaluation of factors influencing augmentative releases of Chrysoperla carnea for control of Scirtothrips perseae in California avocado orchards. - Biological Control 31 (3): 268-275.
Hoddle, MS, Robinson, L & Morgan, D (2002): Attraction of thrips (Thysanoptera : Thripidae and Aeolothripidae) to colored sticky cards in a California avocado orchard. - Crop Protection 21 (5): 383-388.
Humeres, EC & Morse, JG (2006): Resistance of avocado thrips (Thysanoptera : Thripidae) to sabadilla, a botanically derived bait. - Pest Management Science 62 (9): 886-889.
Hoddle, MS, Heraty, JM, Rugman-Jones, PF, Mound, LA & Stouthamer, R (2008): Relationships among species of Scirtothrips (Thysanoptera : Thripidae, Thripinae) using molecular and morphological data. - Annals of the Entomological Society of America 101 (3): 491-500.
Khan, I & Morse, JG (2006): Impact of citrus thrips chemical treatments on the predatory mite Euseius tularensis. - Journal of Applied Entomology 130 (6-7): 386-392.
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.
Mound, LA & Reynaud, P (2005): Franklinothrips; a pantropical Thysanoptera genus of ant-mimicking obligate predators (Aeolothripidae). - Zootaxa (864): 1-16.
Nakahara, S (1997): Scirtothrips perseae (Thysanoptera: Thripidae), a new species infesting avocado in southern California. Insecta Mundi, Vol. 11, No. 2, ppg. 189-192.
Rugman-Jones, PF, Weeks, AR, Hoddle, MS & Stouthamer, R (2005): Isolation and characterization of microsatellite loci in the avocado thrips Scirtothrips perseae (Thysanoptera : Thripidae). - Molecular Ecology Notes 5 (3): 644-646.
Rugman-Jones, PF, Hoddle, MS & Mound, LA & Stouthamer, R (2006): Molecular identification key for pest species of Scirtothrips (Thysanoptera : Thripidae). - Journal of Economic Entomology 99 (5): 1813-1819.
Rugman-Jones, PF, Hoddle, MS & Stouthamer, R (2007): Population genetics of Scirtothrips perseae: tracing the origin of a recently introduced exotic pest of Californian avocado orchards, using mitochondrial and microsatellite DNA markers. - Entomologia Experimentalis Et Applicata 124 (1): 101-115.
Stannard, LJ (1968): The thrips, or Thysanoptera, of Illinois. Illinois Natural History Survey Bulletin 29: 215-552.
Takano-Lee, M & Hoddle, MS (2002): Oligonychus perseae (Acari : Tetranychidae) population responses to cultural control attempts in an avocado orchard. - Florida Entomologist 85 (1): 216-226.
Tollerup, KE & Morse, JG (2005): The effect of horticultural spray oil and surfactants on the residual efficacy of spinosad against avocado thrips, Scirtothrips perseae (Thysanoptera : Thripidae). - Journal of Agricultural and Urban Entomology 22 (3-4): 127-131.
Yee, WL, Faber, BA, Phillips, PA & Rodgers, JL (2003): Comparison of Scirtothrips perseae (Thysanoptera : Thripidae) infestation levels on avocado fruit and leaves. - Florida Entomologist 86 (4): 409-419.
Yee, WL, Phillips, PA & Faber, BA (2001): Effects of aerial spray volume, coverage, and abamectin on Scirtothrips perseae (Thysanoptera : Thripidae). - Journal of Economic Entomology 94 (5): 1090-1096.
Yee, WL, Phillips, PA & Faber, BA (2001): Effects of aerial spray volume, coverage, and sabadilla on Scirtothrips perseae (Thysanoptera : Thripidae). - Journal of Economic Entomology 94 (5): 1085-1089.
Yee, WL, Phillips, PA, Faber, BA & Rodgers, JL (2001): Relationships between Scirtothrips perseae (Thysanoptera : Thripidae) populations on avocado leaves, fruit, and scarring damage on fruit. - Environmental Entomology 30 (5): 932-938.
Yee, WL, Phillips, PA, Rodgers, JL & Faber, BA (2001): Phenology of arthropod pests and associated natural predators on avocado leaves, fruit, and in leaf litter in southern California. - Environmental Entomology 30 (5): 892-898.

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

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