Florithrips traegardhi (Trybom, 1911)

Thripinae, Thripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: 8-segmented antenna, segments III and IV with forked sense cone, terminal segments V-VIII
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Fore wing basal region, clavus
Fig. 6: Fore wing and distal region of fore wing
Fig. 7: Sternite VII
Fig. 8: Tergite VIII with posteromarginal comb

Florithrips traegardhi can cause leaf damage on several grasses, cereal crops and sugar cane. Both sexes macropterous; body light yellow; tip of tarsi dark; antennal segments I & II light yellowish, III-VI basally yellow and distally grey, VII & VIII grey; fore wings very pale yellowish. Antennae 8-segmented; segments III & IV with forked sense cone, microtrichia on III-VI (Fig. 1). Head wider than long; 4 pairs of ocellar setae or more, interocellar pair long and arising on or behind tangent of anterior margin of hind ocelli (Fig. 2). Pronotum with distinct transverse lines of sculpture; with 2 pairs of long posteroangular setae (Fig. 3). Mesosternal furca with median spinula. Metanotum medially with mainly equiangular reticulation; median setae longer than lateral setae and arising at anterior margin; campaniform sensilla present (Fig. 4). Mid and hind tarsi 2-segmented. Fore wings first vein with 2 distal setae; second vein with a complete row of 13-16 setae (Fig. 5 and 6). Tergites laterally and pleurotergites with dense rows of microtrichia along lines of sculpture; tergite VIII with complete posteromarginal comb of long and slender microtrichia (Fig. 8); tergite X without longitudinal split. Sternites without discal setae; median setae of sternite VII arising in front of posterior margin (Fig. 7).
Male similar to female; sternites III-VII each with a transverse glandular area medially.

The genus Florithrips Bhatti, 1970
2 species from Africa, Florithrips dilutus and Florithrips traegardhi are placed in this genus. Florithrips traegardhi, is widespread throughout the Sahel zone from Morocco and Senegal to Bangladesh (Mound & Kibby 1998). The genus is characterised by having 4 pairs of ocellar setae or more, second vein of fore wings with 6 or more setae, tergite X without split, and pleurotergites with dense rows of microtrichia (Bhatti 1969).

Florithrips traegardhi differs from all other species of Thripinae in having 4 pairs of ocellar setae or more (species of other genera with 2 or 3 pairs of ocellar setae). Furthermore, it is one of few species that bears dense rows of microtrichia on pleurotergites and laterally on tergites. Similarly, species of the genus Scirtothrips have pleurotergites and tergites laterally covered with fine microtrichia, but in Scirtothrips these are arranged in closely spaced rows, whereas in Florithrips traegardhi these microtrichia extend along lines of sculpture. In addition, tergites II-VII of Scirtothrips species have a fine comb laterally at posterior margin, and sternites covered with rows of microtrichia, which lacking in Florithrips traegardhi. A few species of the genus Thrips have also pleurotergites covered with many rows of fine microtrichia (Thrips acaciae, Thrips gowdeyi, Thrips simplex, Thrips subnudula, Thrips tabaci), but no microtrichia laterally on the tergites.

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
Crops: amaranthus, beans, capsicum, cashew, groundnut, granate apple, kale, maize, onion, rice, sorghum, sugarcane, tomato, wheat.
Weeds: Acanthospermum hispidum, Bidens pilosa, Senna longiracemosa, Senna occidentalis, Sphaeranthus ukambensis var. ukambensis, Tagetus minuta.

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

Damage and symptoms
The species is common on ears, leaves and leaf-sheaths of many grasses, cereal crops and sugarcane. In large numbers it can cause severe bleaching of the leaves.

Detection and control strategies
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Additional notes
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Biogeography

India, southern Mediterranean, Yemen, Africa. Egypt (Pyramids Road near Cairo; Kerdasa; Gezirah - northern Nile Island in Cairo), Kenya, Morocco, Senegal (Fété Olé), Sudan (Kaka).

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