The black fig fly Silba adipata (Diptera: Lonchaeidae) as an emerging pest in Tunisia: preliminary data on geographic distribution, bioecology and damage

Abstract

Frugivorous fruit flies are considered among the most damaging pests of cultivated fruit crops. The most studied ones are those belonging to the Tephritidae family such as the Mediterranean fruit fly (Medfly) Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). The black fig fly (BFF) Silba adipata McAlpine (Diptera: Lonchaeidae) is a frugivorous monophagous fly species originating from the Mediterranean Basin and the Middle East. Very few data are available in the literature regarding its bioecology, symptoms, distribution and damage. In 2015, severe fruit losses caused by this pest were reported in numerous fig producing areas in Tunisia. In this study we report for the first time the occurrence of this pest in Tunisian fig plantations. Furthermore, laboratory and field observations performed in the main Tunisian fig production areas allowed to address the geographic distribution and the pest status in Tunisia and to characterize its symptoms. We found that the BFF is widely distributed in Tunisia as it was present in all 12 prospected fig producing areas. Moreover, field monitoring of the infestation rates on caprifigs (male fruits) and figs (female fruits) of many cultivars, types (Caprifig, Common, San Perdro and Smyrna) and crops (first and second crops) in three main Tunisia production areas (Djebba, Chott-Mariem and Medenine) allowed to assess its damageability. We showed that it caused high losses on figs and caprifigs. Maximum cumulated infestation rates of caprifigs were registered on cultivar Wedlani (81.25%) in the region of Medenine while the highest infestation rates of figs were registered on the first crops of the San Pedro cultivars Wahchi Thibar (88.17%), Thguegli Thibar (73.98%) and Khenziri (43.75%) in the region of Chott-Mariem. Consequently, the BFF should be probably considered as an emerging economic pest of caprifigs and figs in Tunisia. Possible control methods are explored and discussed.