Thrips Pests

Cluever, Jeffrey D. & Smith, Hugh A., 2017, A photo-based key of thrips (Thysanoptera) associated with horticultural crops in Florida, Florida Entomologist 100 (2), pp. 454-454 : 454-

Key to the Larvae of Common Thrips Pests of Crops in Florida

24. (1’) Annulations on antennal segments III and IV absent; microtrichia on antennal segments III and IV absent ( Fig. 20a )....................................................................................................... Family Phlaeothripidae

24’. — Annulations on antennal segments III and IV present, with microtrichia typically arising from annulations ( Fig. 20b ).......................................................................................................... Family Thripidae , 25

25. (24’) Two setae present on each of sternites IV–VIII ( Fig. 21a ); 12 setae (6 pairs) on pronotum ( Fig. 22a ).............................................................................................................................. Stage I Larva 25’. — Six setae present on each of sternites IV–VIII ( Fig. 21b ); 14 (7 pairs) setae present on pronotum ( Fig. 22b )........ Stage II Larva, 26

26. (25’) Dorsal setae extremely long, length greater than 15 times the diameter of seta socket ( Fig. 23a )................... Scolothrips sp.

26’. — Dorsal setae not extremely long, length less than 10 times the diameter of seta socket ( Fig. 23b )............................. 27

27 (26’) Cuticle heavily stippled, appearing shagreen-like ( Fig. 24a ); cuticle of head heavily reticulated ( Fig. 25 ); dorsal abdominal setae small ( Fig. 24a ).................................................................................. Scirtothrips dorsalis Hood

27’. — Cuticle not stippled, but with oval plaques ( Fig. 24b ); head not heavily reticulated; dorsal abdominal setae moderately enlarged ( Fig. 24b )............................................................................................. 28

28. (27’) Dorsal setae expanded apically ( Fig. 26 ); teeth on posterior margin of tergite IX large, prominent ( Fig. 27a )... Chaetanaphothrips sp.

28’. — Most dorsal setae not greatly expanded apically; teeth on posterior margin of tergite IX small, indistinct ( Fig. 27b,c )............. 29

29. (28’) Sensilla on tergite IX separated by 1.0–1.5 times the space between the D 1 setae................................... Thrips spp.

29’. — Sensilla on tergite IX separated more than 2.0 time the space between the D 1 setae ( Fig. 28 ).................... Frankliniella , 30

30. (29’) Abdominal tergite setae pointed ( Fig. 29a ); microtrichia on plaques of tergite VIII well developed ( Fig. 30 ).................................................................................................... Frankliniella occidentalis (Pergande)

30’. — Abdominal tergites with blunt setae ( Fig. 29b ); microtrichia on plaques of tergite VIII well developed or absent................. 31

31. (30’) Plaques on tergite VIII with well-developed microtrichia ( Fig. 30 ); tergite IX with posteromarginal teeth longer than basal width of D 1 setae ( Fig. 27b )........................................................................ Frankliniella bispinosa (Morgan)

31’. — Plaques on tergite VIII lacking well-developed microtrichia; tergite IX with posteromarginal teeth equal to or shorter than basal width of D 1 setae ( Fig. 27c ).................................................................... Frankliniella schultzei (Trybom)

Figures

Figs. 20–22. Plate IX: Larval antennal, sternite and pronotal characteristics. 20a. Antennal segments with smooth margins, lacking annulations (larval Tubulifera: Phlaeothripidae). 20b. Antennal segments with margins interrupted by annulations, microtrichia arise from these annulations (white arrows) (larval Terebrantia). 21a. Two setae present on each sternite (white arrows) (larva I). 21b. Six setae present on each sternite (white arrows) (larva II). 22a. Twelve setae (6 pairs, D1–D6) on pronotum (Larva I). 22b. Fourteen setae (7 pairs, D1–D7) on pronotum (Larva II).

Figs. 23–26. Plate X: Larval cuticular, abdominal and head characteristics. 23a. Pronotal setae extremely long (white line) (larval Scolothrips). 23b. Pronotal setae not extremely long (white line) (other larval thrips). 24a. Cuticle of abdomen ornamented with small stipples (white box); dorsal setae small (white arrows) (larval Scirtothrips dorsalis). 24b. Cuticle of abdomen ornamented with oval plaques,forming distinct rows (white box); moderate-sized dorsal setae (white arrows) (larvae other species). 25. Cuticle of head patterned with irregularly shaped reticulations (white arrows) (larval Scirtothrips dorsalis). 26. Dorsal setae funnel shaped (white arrows) (larval Chaetanaphothrips).

Figs. 27–30. Plate XI: Larval abdominal characteristics. 27a. Teeth (black arrow) on posterior margin of abdominal segment IX large, prominent (larval Chaetanaphothrips). 27b. Teeth (black arrow) on posterior margin of abdominal segment IX small but longer than basal width of D1 setae; base of D1 seta (white arrow) (larval Frankliniella bispinosa). 27c. Teeth (black arrow) on posterior margin of abdominal segment IX small and equal to or shorter than basal width of D1 setae; base of D1 seta (white arrow) (larval Frankliniella schultzei). 28. Campaniform sensilla (white arrows) on abdominal segment IX separated by 2.0 times the distance (long white line) as compared with the distance (short white line) between D1 setae (larval Frankliniella). 29a. Setae arising from tergites on abdominal segment IX pointed (black arrows) (adult Frankliniella occidentalis). 29b. Setae arising from tergites on abdominal segment IX blunt (black arrows) (adult Frankliniella bispinosa or Frankliniella schultzei). 30. Plaques with well-defined microtrichia (white arrows) on abdominal segment VIII (larval Frankliniella occidentalis or Frankliniella bispinosa).