Journal of Economic Entomology (2015) 108, 1164-1175

Anitha Chitturi, David Riley, Claudia Nischwitz, Ron Gitaitis and Rajagopalbabu Srinivasan (2015)
Thrips settling, oviposition and IYSV distribution on onion foliage
Journal of Economic Entomology 108 (3), 1164-1175
Abstract: Thrips tabaci Lindeman (Thysanoptera: Thripidae) adult and larval settling and oviposition on onion (Allium cepa L.) foliage were investigated in relation to leaf position and leaf length at prebulb plant growth stages under controlled conditions. In the laboratory, four and six adult females of T. tabaci were released on onion plants at three-leaf stage and six- to eight-leaf stage, respectively, and thrips egg, nymph, and adult count data were collected on each of the three inner most leaves at every 2-cm leaf segment. Thrips settling and oviposition parameters were quantified during the light period on the above ground portion of onion plants from the distal end of the bulb or leaf sheath "neck" through the tips of the foliage. Results from studies confirmed that distribution of thrips adults, nymphs, and eggs were skewed toward the base of the plant. The settling distributions of thrips adults and nymphs differed slightly from the egg distribution in that oviposition occurred all the way to the tip of the leaf while adults and nymphs were typically not observed near the tip. In a field study, the foliage was divided into three equal partitions, i.e., top, middle, basal thirds, and thrips adults by species, primarily Frankliniella fusca (Hinds) and T. tabaci, were collected from each partition to determine if there was a similar bias of all adult thrips toward the base of the plant. The results suggested that adults of different species appear to segregate along leaf length. Finally, thrips oviposition on 2-cm segments and Iris yellow spot virus positive leaf segments were quantified in the field, irrespective of thrips species. Both variables demonstrated a very similar pattern of bias toward the base of the plant and were significantly correlated.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): David G. Riley, Rajagopalbabu Srinivasan, Claudia Nischwitz

Research topic(s) for pests/diseases/weeds:
transmission/dispersal of plant diseases
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Thrips tabaci	Onion/garlic/leek (Allium)
	Orthotospovirus iridimaculaflavi	Onion/garlic/leek (Allium)
	Frankliniella fusca	Onion/garlic/leek (Allium)