Petal-feeding behavior of Liriomyza trifolii in gerbera cut-flower production

Liriomyza trifolii (Burgess) has been an important economic pest of horticultural and ornamental crops for over 30 years. Cut-flowers, in particular, have been an especially vulnerable commodity. Adult females puncture the leaf's surface during ovoposition and feeding, resulting in a stippled appearance to leaves. However, the major source of damage is caused by larvae, which tunnel through mesophyll tissue, leaving behind serpentine trails. Gerbera, unlike many other cut-flowers, are sold without leaves and have therefore been able to sustain large populations without great economic loss. Recently, however, at least one grower has experienced an increased incidence of petal feeding and petal-oviposition by adult flies, thereby elevating this pest to a new level of severity. This study tests the benefits of petal-feeding behavior by assessing longevity and fecundity of adult flies with access to flowers, leaves or both. Preliminary results indicate that flower-feeding increases the lifespan and fecundity of adult flies. Possible reasons for the increased incidence of this behavior are explored.