Economic damage by
onion thrips infestation is caused by bot h nymph and
adult feeding on green leaf parts. They feed by piercing
surface tissues and suck up the exuded cellular contents.
The empty cell s show silvery-white spots on the leaf
surface, which are referred to as silver damage. As a
consequence, particularly leek plants become unmarketable
(Cr. uger, 1991) Besides qualitative losses, quantitative
yield reductions in leek (Vierbergen and Ester,
2000) and onions (Kendall and Capinera, 1987) occur as
well.