Dactylopius opuntiae (Hemiptera: Dactylopiidae) as a Diet Source for Mass Rearing Cryptolaemus montrouzieri (Coleoptera: Coccinelidae).

Although natural enemies play an important role in most integrated pest management programs, biological control agents remain poorly adopted in food production systems primarily due to the high costs associated with their implementation. Cryptolaemus montrouzieri (Mulsant, 1853) is a very promising candidate for the biological control of mealybugs. However, mass rearing of this predator is critical to provide sufficient numbers so that effective control of mealybugs can be achieved. Thus, this work focuses on mass rearing of this biological control agent under controlled conditions at T = 28 ± 1 °C, RH = 70 ± 5%, and 12:12-h photoperiod L:D. This experiment was based on feeding this predator three diets: a freeze-dried artificial food source, the cactus cochineal-Dactylopius opuntiae (Cockerell, 1929), and a combination of the two diets. The fecundity recorded in the freeze-dried artificial food, D. opuntiae, and mixed diet was 2.73, 8.79, and 8.78 larvae/female, respectively. The sex ratios (male:female) of the cochineal adults that emerged on the three diets were 1:1.35, 1:1.23, and 1:1.11, respectively, for the freeze-dried artificial food, D. opuntiae, and mixed diet. The emerged adults had an average weight of 9.2 mg when fed the artificial diet, 13.8 mg for the D. opuntiae diet, and 9.5 mg for the mixed diet, while the life cycle duration for each diet was 50.1, 43.5, and 42.3 d, respectively. At the beginning of the C. montrouzieri rearing process with 40 adults, our results indicated that an average of 1031.1 adults can be produced using D. opuntiae as the diet in a volume of 1 m3. The D. opuntiae diet is recommended due to its overall lower costs. Additionally, this study indicates that mass-rearing of C. montrouzieri can be achieved with cheaper and more readily available materials for diets, instead of purchasing a freeze-dried artificial food source.

Chemical Composition, Antioxidants, Antibacterial, and Insecticidal Activities of Origanum elongatum (Bonnet) Emberger & Maire Aerial Part Essential Oil from Morocco.

The aim of this research is to profile the chemical composition of the essential oil (EO) extracted from the aerial parts of Origanum elongatum (O. elongatum) and to evaluate its antioxidant, antibacterial and insecticidal activities on Ceratitis capitata adults. Gas chromatography coupled with mass spectrometry (GC/MS) revealed a total of 27 constituents in EO of O. elongatum, which accounted for 99.08% of its constituents. Carvacrol (57.32%) was a main component, followed by p-cymene (14.70%) and γ-terpinene (9.84%). The antioxidant activity of O. elongatum EO was investigated using DPPH (1,1-diphenyl-2-picrylhydrazyl), FRAP (Ferric reducing antioxidant power), and TCA (the total antioxidant capacity) methods. This EO exhibited a remarkable antiradical and reducing power against DPPH (IC50 = 2.855 ± 0.018µL/mL), FRAP (EC0.5 = 0.124 ± 0.013µL/mL) and TCA (IC50 = 14.099 ± 0.389 mg AAE/g of the EO). The antibacterial tests in vitro, using the disc and dilution methods, were carried out on nine pathogenic bacteria isolated from the hospital patients, such as Enterococcus faecalis, Serratia fonticola, Staphylococcus aureus, Acinétobacter baumannii, Klebsiella oxytoca, Klebsiella pneumoniae sensible, E.coli sensible, E.coli resistante, and Enterobacter aerogenes. The EO demonstrated a considerable antibacterial activity with minimum inhibitory concentrations (MIC) from 2 to 8 µL/mL against all strains except Staphylococcus aureus (MIC = 32 µL/mL). Regarding the insecticidal activity, the fumigation test indicated a high efficacy (100% mortality), and a lethal dose of LD50 = 17 ± 0.53 µL/L air was found after 24 h of exposureTherefore, O. elongatum EO could be utilized as a natural antioxidant, antibiotic and biopesticides.

Chemical Composition and Bioinsecticidal Effects of Thymus zygis L., Salvia officinalis L. and Mentha suaveolens Ehrh. Essential Oils on Medfly Ceratitis capitata and Tomato Leaf Miner Tuta absoluta.

The present work was aimed to study the toxicity of the essential oils of three aromatic and medicinal plants on the tomato leaf miner Tuta absoluta and the Medfly Ceratitis capitata as an alternative to conventional pesticides. We carried out a phytochemical and insecticide study of T. zygis L., S. officinalis L. and M. suaveolens Ehrh. essential oils (EOs) through the study of their chemical composition and their toxicity on C. capitata adults and T. absoluta larvae. The extraction of the EOs by hydrodistillation showed yields of 3.87 ± 0.03, 4.09 ± 0.23 and 4.35 ± 0.11 for T. zygis, S. officinalis L. and M. suaveolens Ehrh., respectively. The identification of the chemical composition of the EOs by GC/MS showed that oxygenated monoterpenes constituted the most abundant group for all the extracted EOs. The major compounds were rather diversified depending on plant species. In fact, the S. officinalis L. EO mainly contained trans-thujone (21.80 %), the M. suaveolens Ehrh. EO mainly contained piperitenone oxide (71.19%), and carvacrol (61.60%) was the main component of the T. zygis L. EO. An insecticidal effect was observed for the three studied EOs on C. capitata adults and T. absoluta larvae. The observed LD50 values were 0.80 µL/mL and 11.04 µL/mL for M. suaveolens and S. officinalis, respectively, on T. absoluta larvae. For C. capitata adults, the obtained LD50 values were 0.9 µL/mL and 11.78 µL/mL for M. suaveolens and T. zygis, respectively. The presented findings could contribute to the development of biopesticides for plants as a component of integrated pest management strategies in citrus and tomato crops.

Self- and Cross-Pollination in Argane Tree and their Implications on Breeding Programs.

The argane tree (Argania spinosa L.) is a mostly self-incompatible species that must be cross-pollination. However, the cross-pollination is often insufficient to obtain a desirable fruit yield in the absence of compatibility between the orchard's argane trees. Proper pollination design is therefore essential to ensure a supply of compatible pollen. In this study, pollen germination and pollen development following cross- and self-pollination were investigated in A. spinosa. The choice of compatible parents or a pollinizer is currently a new research topic for the production of argane fruits in the framework of argane farming programs. Different pollination experiments were designed with two main objectives: (i) to study cross/self-(in)compatibility in the argane tree, and (ii) to determine the degree of compatibility between selected superior genotypes for pollination strategies to improve fruit set in argane orchards. Thus, to determine if a pollination deficit exists, experiments were carried out on 14 genotypes, and 5421 flowers served as sampling. The germination rate of pollen was lower than 50% for three genotypes, and only four genotypes bloom twice a year. From cross-pollination trials, traits related to the mother trees, such as the shape of the fruit and fruit ripening duration, are not influenced by the gene flow transmitted by pollens. Self-pollination was very low (0.2%) for both hand- and free self-pollination but the highest fruit set rate observed was 5.3%. Based on the pollen effect study results, it can be concluded that different pollen sources affected the fruit set. Thus, the choice of an efficient pollinizer genotype must be inter-compatible with the main variety, bloom at the same time, and be regular (no alternation). This is the first time that a pollinizer tree was reported and studied for argane. To meet future argane farming requirements, the number and location of compatible pollinizers is very important in the argane orchard design. This design of pollination remains to be checked by alternately planting a row of pollinizer trees or inter-rows with main varieties.

Chemical Composition and Insecticidal Potential of Six Essential Oils from Morocco against Dactylopius opuntiae (Cockerell) under Field and Laboratory Conditions.

The carmine cochineal Dactylopius opuntiae (Cockerell) is the major insect pest of the prickly-pear cactus Opuntia ficus-indica (L.) in Morocco. The present study investigated the insecticidal activities of six essential oils (EOs) against nymphs and adult females of D. opuntiae applied singly or in combination with a detergent under laboratory and field conditions. Under laboratory conditions, M. pulegium and O. vulgare L. essential oils showed a high level of insecticidal activity at 5%, with 98% and 92% females' mortality, respectively, 5 days after treatments. The M. pulegium and O. vulgaris oils at 5% applied in combination with black soap at (60 g/L) induced the highest toxic activity on adult females, 100% and 96% at 5 days after treatments, respectively. Under field conditions, M. pulegium and O. vulgare oils at 5% in combination with black soap (60 g/L) showed the highest adult female mortalities with 96.33 and 92.56%, respectively, 7 days after the first application. The double application of M. pulegium oil at 5% significantly increased the mortality of adult females up to 91%, 5 days after the second spray. GC-MS analysis revealed that the most abundant constituent of M. pulegium and O. vulgare oils was pulegone (84.69%) and durenol (76.53%), respectively. These findings showed that the use of M. pulegium and O. vulgare in combination with black soap or in double sprays could be incorporated in the management package for the control of the wild cochineal D. opuntiae, as a safe and natural alternative to chemical insecticides.

Diversity of entomopathogenic fungi associated with Mediterranean fruit fly (Ceratitis capitata (Diptera: Tephritidae)) in Moroccan Argan forests and nearby area: impact of soil factors on their distribution.

BACKGROUND: Studying the ecology of biocontrol-agents is a prerequisite to effectively control medfly (Ceratitis capitata (Diptera: Tephritidae)) with entomopathogenic fungi. In this context, factors affecting the occurrence and distribution of medfly-associated entomopathogenic-fungi were studied. Soil samples (22) were collected from natural and cultivated areas of Souss-region Morocco. RESULTS: A total of 260 fungal isolates belonging to 22 species and 10 genera were obtained by using medfly pupae as bait. Medfly-associated fungi were detected in all studied soils and pupae infection percentages ranged from 3.33% to 48%. Two genera, Fusarium and Beauveria were the most frequent with 83 isolates (32%) and 50 isolates (19.23%) respectively. Pathogenicity test of isolated species against medfly pupae showed high mortality rates up to 91% for some strains. Principal component analysis (PCA) demonstrated a strong influence of origin, physical, and chemical properties of soil on the abundance of these fungi. In general, medfly-associated fungi were more abundant in soils with moderate pH (7.5 to 8) having high sand and organic content. High relative humidity negatively influenced the abundance of these fungi. Both factors directly affected the fungal infection percentages in pupae. The response of fungi to these parameters varied among species. According to principal component analysis (PCA), the soils of argan fields and forests were more suitable for the development of medfly-associated fungi than citrus orchards. CONCLUSIONS: These results guide identifying suitable soils for the effective application of entomopathogenic fungi as biological control agents. In summary, isolated indigenous strains seem to be a promising option to control C. capitata.

Inoculation of tomato plants with rhizobacteria suppresses development of whitefly Bemisia tabaci (GENNADIUS) (HEMIPTERA: ALEYRODIDAE): Agro-ecological application.

In agroecosystems, soil biodiversity is increasingly becoming more recognized as providing benefits to both plants and human health. It performs a wide variety of ecological services beyond the recycling of nutrients to plant growth and manage pests and diseases below the economic injury level. This study investigated the effects of three Pseudomonas isolates (Q172B, Q110B and Q036B), isolated from untreated tomato rhizospheric soil, as a biological control agent of Bemisia tabaci which is a key pest of tomato crops. The study was conducted under laboratory and glasshouse conditions and the water treatment was used as a control. Adult mortality rates were assessed during three days at 24h interval and larva mortality rates were evaluated during six days after treatment at 48h interval. Results indicate that Q036B isolate has a faster effect on B. tabaci adult and larvae. Under laboratory conditions, all three Pseudomonas isolates (Q110B, Q036B and Q172B) have a significant effect on B. tabaci adult mortality compared to control. The earliest and the most important mortality rate of 76% was recorded by Q036B. Two isolates Q036B and Q110B caused a significant mortality on B. tabaci larvae; with highest mortality effect (79%) was observed for Q036B compared to control. However, Q172B has no mortality effects on B. tabaci larvae under laboratory conditions. In glasshouse conditions, only Q036B provided high mortality rates of 91% at 168h after treatment. The results of this study indicate that the Pseudomonas isolate Q036B significantly suppresses B. tabaci in tomato plant and could substitute the excessive use of chemicals. Current research indicates that soil biodiversity could be promising to preserve agro-ecological sustainability.