Report of first investigations on phytophagous and predatory mites in cork oak (Quercus suber L.) trees in Tunisian forests
Abstract: During the last decades, in the early 1980’s, cork oak forests have suffered from degradation and depletion. The reasons are diverse but the incidence of pests and diseases can be pointed out as a triggering factor for the decline process. The impact of these biotic agents is of big concern, especially in a scenario of climatic changes, with a pronounced increase in the occurrence and severity of extreme temperatures and drought. In fact, numerous species of defoliators, gall wasps and bark and ambrosia beetles, were reported in Tunisia. However, as far as we know, there are no studies on the mites in Tunisian forests and their putative contribution to cork oak decline and loss of biodiversity, although several studies have already been conducted worldwide on Quercus species. The objective of the current work is to make an inventory of mites occurring in cork oak forests in four sites in the North West of Tunisia (Ain Boulahia, Ain Snoussi, Babouch, and Homran). Four trees were randomly selected in each site and one hundred leaves per tree were sampled during 2018. Results revealed the presence of six genera of Acari belonging to five families: Brevipalpus (Tenuipalpidae), Eotetranychus (Tetranychidae), Zetzellia (Stigmaeidae), Bariella (Eriophyidae), Typhlodromus and Typhloseiulus (Phytoseiidae). Our results showed that cork oak trees host both predatory and phytophagous mites with high diversity in mites’ communities. Further surveys at a larger scale would be important to complete the inventory. Besides, studies regarding bio-ecology of predatory families and their contribution in biological control and balance are essential, namely in a context of global climate modifications and risk of invasive species.