**1. Introduction**

The date palm trees have many important socio-economic and ecological roles in oases ecosystems [1]. In North Africa and in Morocco, the oases are facing several constraints related to urbanization, drought, salinity, desertification, poor soils in organic matter and nutrients, genetic erosion, aging, diseases like Bayoud palm caused by *Fusarium oxysporum* fsp *albidinis* [2–4] and pests attacks [5, 6]. Palm trees are strongly threatened by the red weevil caused by *Rhynchophorus ferrugineus,* which causes huge economic losses [7]. The red weevil causes economy loss, resulting in millions of dollars each year, related to agricultural production or costs related to pest control [8]. In the Gulf countries and the Middle East, US\$ 8 million is spent every year to cut

down contaminated trees [8, 9]. In Spain, red palm weevil has appeared since 1999 and damaged almost 20,000 palms of *Phoenix dactylifera* [10]. In the North of Morocco and more precisely in Tangier, the number of *Phoenix canariensis* prospected during 2009–2016 is 244,393 [11]. The number of *P. canariens is* infested with *R. ferrugineus* was 904, which 896 were incinerated [11], whereas no *P. dactylifera* has been infested with *R. ferrugineus*. In Morocco, *Potosia opaca* var. cardui Gyllenhal has been observed for the first time by Meddich and Boumezzough [12]. Indeed, in Marrakesh and Errachidia regions, it attacks *P. dactylifera* L. and *P. canariensis* by consuming their wood, which causes faster degradation. Thus, to remedy the damage caused by *P. opaca*, most farmers were forced to use synthetic pesticides. However, the intensive use of these pesticides are generally effective in protecting crops [13], but they are toxic to wildlife and to organisms from different levels of the ecosystems [14–17]. Over time, the permanent use of insecticides may be accompanied by the development of resistant strains in some treated species. Biocontrol strategies for pests need to be investigated and developed to provide an ecological substitute or alternative approach to the conventional methods. Some sub-products such as olive oil mill waste waters (OMW) are currently used to control pests, which is essential for crop protection [18, 19]. Most of the OMW phenolic compounds derived from olive polyphenols have many other biological properties [20, 21], as well as biocide activities [22] and phytotoxic effects [23]. Due to their particular characteristics, these effluents are a serious problem for the Mediterranean region, which annually produce around 30 million m3 of OMW with a damaging effect on the environment [23] and accounts for approximately 95% of olive oil production in the world [19]. In addition, different physicochemical methods have been proposed to treat OMW, including natural and forced evaporation [24], electro-coagulation [25], oxidation by ozone and Fenton reagent [26] as well as their agricultural spreading [21], which is an alternative among the suggested solutions. However, the agronomic application of OMW is limited by the doses to be applied and the risk of polyphenols accumulation in the soil after consecutive applications [21–27]. In parallel with researches made on the treatment of OMW, many studies have been carried out aiming the recovery of OMW phenolic compounds. Recent studies tried to take its advantage from the antimicrobial and phytotoxic properties by using it as biopesticide for crops protection [28–30] or as insecticides to control *P. opaca* larvae [31]. This contribution summarized the quality of palm health status, OMW characteristics and its application as insecticides to control *P. opaca* larvae in date palm, especially in *P. dactylifera* L.
