**3.3 Breeding of larva and nymphs**

After one month of larval rearing, the majority of stage III (L3) larvae are transformed into nymphs (the last stage before adult release) [12]. At the end of the last stage of development, the larva becomes more yellowish (accumulation of adipose tissue to the detriment of the stercoral volume of the rectal sac). The premymphal phase lasts a few days during which the elderly larva (L3) no longer feeds and migrates to the bottom of the substratum to build a pupal cocoon, which it generally chooses to make against a support (**Figure 5**).

Pupation occurs in the dorsal position since the larvae move on the back, which distinguishes them from Oryctes larvae (Rhinoceros). In general, its cycle development from the egg to the imago known to be set on one year [40]. However, its metabolic activity is closely related to the ambient temperature, the low temperatures slow down this passage, which may last 2 years [40]. The oases, Moroccan as already said are relatively warm, which could privilege this passage. The nymph of brown-orange color has appendages entirely free and folded down on its ventral surface. During this critical phase of development, the insect does not feed, its mobility is very limited and it is very dependent on the conditions of the environment (temperature, humidity and predation). During this passive stage of development, the nymph gradually acquires a darker color. This pigmentation is perfected in the days before the molt. On the occasion of this final metamorphosis, the insect takes a ventral position, in order to facilitate the deployment of wings and elytra. Its tissues harden progressively in the presence of oxygen from the air. After gaining greater rigidity, the adult perforates its cocoon and migrates to the surface of the substrate in order to begin its phase of aerial life. The adult that has just hatched is sometimes still a little soft and often presents colors less sustained and clearer than its older congeners (**Figure 6**) [12].

Examination of adults under binocular loupe and using a dichotomous key and reference collections from the laboratory led us to the species of Coleoptera Scarabaeidae: *Potosia opaca* var. Cardui Gyllenhal. This species varies greatly in size (from 14 to 24 mm), its morphology with the sides of the pronotum, which can

**Figure 4.** *Larvae found in the palm crown (*P. canariensis*) (A) and (B) larvae, (C) leaf base.*

**497**

*Use of Olive Mill Wastewaters as Bio-Insecticides for the Control of* Potosia Opaca *in Date Palm…*

be weakly indented before the posterior angles, or not indented. The, the general coloring on the topis black, passes more rarely to the black green (typical form) and even to bronze and green with coppery metallic reflection. On the underside, the color is sometimes black, sometimes bluish, or sometimes greenish or white.

**Table 2** shows the physicochemical characteristics of the OMW according to Boutaj et al. [31]. In addition, these effluents have an acidic pH of 4.7, a high electrical conductivity of 23.5 mS/cm, a residual oil of 2.2 g/L, a high polyphenol content of 8.38 g GAE/L of crude OMW, and an average dry matter content of 94.86 g/L.

As described by Boutaj et al. [31], OMW present a high phenol content. **Table 3** summarizes the qualification and quantification of these principal phenolic compounds identified by HPLC analysis. Based on comparisons of their retention times and their UV spectra with standards analyzed under the same conditions, 10 free compounds were provisionally identified and quantified in crude OMW (**Table 3**). HPLC analysis revealed that the two main monomeric phenolic compounds in OMW

The effect of OMW spray on the larvae was significantly important compared to the control larvae sprayed with distilled water (**Figure 7**). Over time, larvae treated with OMW showed a significant weight loss from 2.38 to 2.02 g after 216 h. In contrast, the negative control was increased from 2.38 to 2.45 g after 168 h, and then decreased slightly from 2.41 to 2.39 g from 192 to 456 h. In comparison with the crude OMW and the negative control, the two positive controls (Cordus and Kemaban) showed a significant difference (**Figure 7**). Indeed, Cordus is a very effective insecticide resulting from the combination of

*3.4.2 Identification and quantification of OMW phenolic compounds*

**3.5 Olive mill wastewater as bio-insecticides to control** *P. OPACA*

were hydroxytyrosol (0.248 g/L) and tyrosol (0.201 g/L).

*DOI: http://dx.doi.org/10.5772/intechopen.93537*

**Systematic**

**Figure 6.**

Coleoptera, Scarabaeidae Cetoniini

Hexapoda (Insecta)

*Potosia opaca* Fabricius.

*3.5.1 Weight loss of treated larvae*

**3.4 Olive mill wastewater characteristics**

*3.4.1 Physicochemical characteristics of crude OMW*

*Adult observed in its damaged cocoon (A), (B) and (C) free adults.*

**Figure 5.** *Observed cocoons (A) and nymphs (B).*

*Use of Olive Mill Wastewaters as Bio-Insecticides for the Control of* Potosia Opaca *in Date Palm… DOI: http://dx.doi.org/10.5772/intechopen.93537*

#### **Figure 6.**

*Biotechnological Applications of Biomass*

**3.3 Breeding of larva and nymphs**

chooses to make against a support (**Figure 5**).

After one month of larval rearing, the majority of stage III (L3) larvae are transformed into nymphs (the last stage before adult release) [12]. At the end of the last stage of development, the larva becomes more yellowish (accumulation of adipose tissue to the detriment of the stercoral volume of the rectal sac). The premymphal phase lasts a few days during which the elderly larva (L3) no longer feeds and migrates to the bottom of the substratum to build a pupal cocoon, which it generally

Pupation occurs in the dorsal position since the larvae move on the back, which distinguishes them from Oryctes larvae (Rhinoceros). In general, its cycle development from the egg to the imago known to be set on one year [40]. However, its metabolic activity is closely related to the ambient temperature, the low temperatures slow down this passage, which may last 2 years [40]. The oases, Moroccan as already said are relatively warm, which could privilege this passage. The nymph of brown-orange color has appendages entirely free and folded down on its ventral surface. During this critical phase of development, the insect does not feed, its mobility is very limited and it is very dependent on the conditions of the environment (temperature, humidity and predation). During this passive stage of development, the nymph gradually acquires a darker color. This pigmentation is perfected in the days before the molt. On the occasion of this final metamorphosis, the insect takes a ventral position, in order to facilitate the deployment of wings and elytra. Its tissues harden progressively in the presence of oxygen from the air. After gaining greater rigidity, the adult perforates its cocoon and migrates to the surface of the substrate in order to begin its phase of aerial life. The adult that has just hatched is sometimes still a little soft and often presents

colors less sustained and clearer than its older congeners (**Figure 6**) [12].

*Larvae found in the palm crown (*P. canariensis*) (A) and (B) larvae, (C) leaf base.*

Examination of adults under binocular loupe and using a dichotomous key and reference collections from the laboratory led us to the species of Coleoptera Scarabaeidae: *Potosia opaca* var. Cardui Gyllenhal. This species varies greatly in size (from 14 to 24 mm), its morphology with the sides of the pronotum, which can

**496**

**Figure 5.**

**Figure 4.**

*Observed cocoons (A) and nymphs (B).*

*Adult observed in its damaged cocoon (A), (B) and (C) free adults.*

be weakly indented before the posterior angles, or not indented. The, the general coloring on the topis black, passes more rarely to the black green (typical form) and even to bronze and green with coppery metallic reflection. On the underside, the color is sometimes black, sometimes bluish, or sometimes greenish or white.

**Systematic** Hexapoda (Insecta) Coleoptera, Scarabaeidae Cetoniini *Potosia opaca* Fabricius.

#### **3.4 Olive mill wastewater characteristics**

### *3.4.1 Physicochemical characteristics of crude OMW*

**Table 2** shows the physicochemical characteristics of the OMW according to Boutaj et al. [31]. In addition, these effluents have an acidic pH of 4.7, a high electrical conductivity of 23.5 mS/cm, a residual oil of 2.2 g/L, a high polyphenol content of 8.38 g GAE/L of crude OMW, and an average dry matter content of 94.86 g/L.

### *3.4.2 Identification and quantification of OMW phenolic compounds*

As described by Boutaj et al. [31], OMW present a high phenol content. **Table 3** summarizes the qualification and quantification of these principal phenolic compounds identified by HPLC analysis. Based on comparisons of their retention times and their UV spectra with standards analyzed under the same conditions, 10 free compounds were provisionally identified and quantified in crude OMW (**Table 3**). HPLC analysis revealed that the two main monomeric phenolic compounds in OMW were hydroxytyrosol (0.248 g/L) and tyrosol (0.201 g/L).

#### **3.5 Olive mill wastewater as bio-insecticides to control** *P. OPACA*

#### *3.5.1 Weight loss of treated larvae*

The effect of OMW spray on the larvae was significantly important compared to the control larvae sprayed with distilled water (**Figure 7**). Over time, larvae treated with OMW showed a significant weight loss from 2.38 to 2.02 g after 216 h. In contrast, the negative control was increased from 2.38 to 2.45 g after 168 h, and then decreased slightly from 2.41 to 2.39 g from 192 to 456 h. In comparison with the crude OMW and the negative control, the two positive controls (Cordus and Kemaban) showed a significant difference (**Figure 7**). Indeed, Cordus is a very effective insecticide resulting from the combination of two active substances, whose weight loss was similar to that of OMW for the two doses applied. The greatest weight loss over the first three days compared to the other treatments was achieved at a dose of 1 μL/mL, which resulted from the slow decrease in weight. Then, a more or less similar weight loss was observed for both doses. Kemaban insecticide is formed by a single active substance and resulted in significant weight loss at both doses compared to control and other treatments (Cordus and OMW) (**Figure 7**). Significant weight loss was seen during the first 4 days at a dose of 1 μL/mL of Cordus compared to 0.5 μL/mL of Kemaban. Thereafter, weight loss was found to be almost similar until 174 h, and then became slight and stable at a dose of 1 μL/mL until 224 h. The stability was the result of larval death.
