LEAF MINING FLIES - IMPORTANT PESTS OF CUCURBITS

Sa？etak Leaf-mining flies (Agromyzidae) is a family of small yellow and black coloured flies, whose larvae cause damage on cultural plants by tunnelling into the leaf tissue between upper and lower leaf surfaces, creating characteristic ？mines“. Females cause additional damage by creating small round feeding and oviposition punctures on upper leaf surface. The most important pests of cucurbits are four polyphagous species: Chromatomyia horticola (Goureau, 1851), Liriomyza trifoli (Burgess, 1880), Liriomyza bryoniae (Kaltenbach, 1858) and Liriomyza huidobrensis (Blanchard, 1926). The life-cycle of leaf-mining flies comprises following stages: egg, three larval instars, a pupal instar and adult fly. Leaf-mining flies develop numerous, overlapping generations throughout the year, especially in greenhouse conditions. “Mines” and punctures made by female flies greatly reduce photosynthesis and can lead to desiccation and premature leaf-fall that subsequently reduces yield and fruit quality. As a result of the damage caused by leaf-mining flies, seedlings and young plants can be totally destroyed. Control of leaf-mining flies is very difficult, particularly in protected cucurbits due to many generations these pest have during a year, fast development of resistance to most commonly used insecticides and larvae being hidden inside the “mines” in leaves. Also, there is currently a lack of registered products on the market in Croatia for the chemical control of these pests. Therefore, IPM must be applied for the efficient control of leaf-mining flies in cucurbits, including all available cultural, physical and biological measures