**5. Conclusions and future directives**

*Biotechnological Applications of Biomass*

sexual confusion may be a means.

the core of in any integrated pest management [48–50].

• Also, use entomo-pathogenic nematodes with a dose of 180 million nematodes per 100 L of water, which act by reducing the size of the larvae and consequently affect the number of female adults capable of laying the eggs.

• Trapping control using pheromones. The use of such specific substances for

Efforts now focus on the development of integrated pest management methods based on biological control and pheromone traps rather than on conventional insecticides [45]. Since it is an internal tissue borer, *R. ferrugineus* is difficult to control in the early stage of attack [38–46]. Initial efforts to control red palm weevil in the Kingdom of Saudi Arabia using chemical insecticides were failed [47]. An integrated pest management strategy, developed in India, has successfully suppressed the pest in the date plantations in the Kingdom of Saudi Arabia [38]. The strategy is modeled on the lines of tackling the pest on coconut. The pheromone traps has been used successfully to monitor and mass attract the pest, and it could be considered as

There is a great danger from chemicals such as insecticides and fungicides in human's food and animal use. Recognizing this real danger, farmers and consumers turned their efforts to environmental and eco-friendly practices by using as well as consuming biological and healthy products. The polyphenols are natural molecules present in OMW from the olive fruit which could be an alternative and an asset for pest control. However, the amount of OMW polyphenols may vary based on multitude factors, such as climatic conditions, olive variety and fruit ripening stage as well as the harvest period [51–53]. The OMW phenolic compounds content, can be considerably affected by the technological processes used for olive oil extraction [54]. In this context, the phenolic compounds content of OMW which, presented potential insecticidal activity has been assessed and investigated by Boutaj et al. [31] in view to develop new valorization strategies. Additionally, an application of a hydroxytyrosol-rich OMW extract by spraying it against olive psyllid (*Euphyllura olivine*), in a drip-irrigated olive orchard for evaluating the insecticidal activity of OMW, was carried out in 2008 and 2009 [29]. The extract from OMW had a strong insecticidal activity control this insect when the applied concentration was 2 g/L. In addition, the authors observed a significant biocide effect depending on OMW phenolic extracts concentration on *E. olivina* larvae as well as adults. Indeed, OMW showed similar toxicity to the Kemaban insecticide at 0.5 μL/mL dose. Nevertheless, it is clear that the obtained results were attributed to the chemical molecules that contain the two commercial insecticides. Cordus presents two active molecules namely chlorpyriphos ethyl and cypermethrin. As for Kemaban contains a single active molecule which, is chlorpyriphos ethyl. These molecules act on the spread of nerve impulses along the axon (cypermethrin action) and inhibit the acetylcholine esterase by blocking the transmission of the nerve flux (chlorpyriphos ethyl action) [55, 56]. The main mechanisms which explain the OMW's biocide effect on invasive species in general including insects are not clarified. It has been suggested that the transmission of the nerve flux may be blocked by the high phenolic compounds content in OMW [57, 58]. A significant inhibition of acetylcholine esterase activity in a marine mollusk (*Mytilusgallo provincialis*) has been reported by Danellakis et al. [57] after exposition to OMW. While, Campani et al. [58] reported that the inhibition of acetylcholine esterase may be attributed to the potential presence in OMW of organophosphates and carbamates, two pesticides which, are strong inhibitors of acetylcholine esterase activity and commonly used to treat the olive fruit fly (*Bactroceraoleae*). However, the authors did not dismiss the inhibition of acetylcholine esterase possible which, could be explained, by the phenolic

**502**

In this chapter, we present a new eco-friendly approach to control the spreading of *P. opaca* which started in Morocco. Microbiological analysis show the presence of saprophytic fungi and genus *Fusarium* with a non-virulent strain. On the other hand, the two insecticides used separately and crude OMW are toxic on *P. opaca* var. Cardui Gyllenhal larvae. These results are promising and suggest the possibility of using OMW due to their high content of phenolic compounds as a means of biological control to overcome environmental problems caused by synthetic pesticides. The OMW and their phenolic extract compounds could be used in agricultural systems. Moreover, focused field researches (each plant-pathogen system) could be carried out to understand and evaluate the effects of OMW on specific *in situ* pest problems. Based on the main findings, it is clear that OMW may contribute to improve the date palm protection to control *P. opaca* and could be used as bioinsecticides. Nevertheless, OMW could be used safely as a challenge to control plant pest without affecting negatively the soil and plants. Besides, the use of OMW combined with other pest bio-control practical methods which could be a sustainable approach to minimize the potential risks. In this context and to understand the beneficial effects of OMW, more investigations could be required to assess the feasibility of OMW application in bio-controlled systems at large-scale, and determining the limitations and advantages on the long term. Further, research works are needed to test, besides crude OMW, pretreated OMW (ultra-filtered or heated) and its phenolic extracts as biodegradable pesticides.
