The use of essential oils has emerged as an ecofriendly solution for controlling different pests, particularly insects of stored products. Essential oils (EOs) from Thymus capitatus (TC) and Origanum compactum (OC) have received less attention for these bioactivities. Therefore, our study aimed to assess the repellent, antifeedant and contact toxicity of their EOs against a major stored product pest Tribolium castaneum. Besides, GC-MS was also carried out to determine the compounds responsible for the observed bioactivities. Regarding contact toxicity, LC50 values were 0.58 and 0.35 µL/cm2 for TC and OC after 24 h of exposure, respectively. For the repellent effect, the percentage of repellency (PR) was variable across different concentrations and exposure durations. TC exhibited the best PR (98%) after 3 h of exposure at 0.031 µL/cm2. For prolonged repulsive effect (24 h), TC sustained its repulsive efficacy with a PR of 90% at 0.062 µL/cm2 followed by OC with a PR of 88% at 0.125 µL/cm2. As for the antifeedant effect, both EOs had a significant impact on nutritional indexes, especially the feeding deterrent index and relative consumption rate. OC displayed a notable effect, causing 59% of feeding deterrence at 1.92 µL/pellet. These multifaced effects can be explained by the high content of carvacrol in both EOs (OC: 90% and TC: 78%). These multifaced effects demonstrated through different exposure routes and bioassays promote the use of T. capitatus and O. compactum EOs as a sustainable management strategy to control T. castaneum.
The Opuntia ficus-indica (L.) cactus, a crucial crop in Morocco, is threatened by the wild cochineal, Dactylopius opuntiae (Cockerell). The aim of this research was to investigate the efficacy of nine bacterial strains against both D. opuntiae nymphs and adults females applied individually or after black soap in the laboratory, greenhouse, and field conditions. Using the partial 16S ribosomal DNA, the bacterial isolates were identified as Pseudomonas koreensis, Pseudomonas sp., Burkholderia sp. and Bacillus sp. Under laboratory conditions, the insecticidal activity of P. koreensis strain 66Ms.04 showed the level mortality (88%) of adult females' at 108 CFU/mL, 7 days after application. At a concentration of 108 CFU/mL, P. koreensis strain 66Ms.04 and Pseudomonas sp. (strains 37 and 5) caused 100% nymphs mortality rate three days after application. Under greenhouse conditions, the use of P. koreensis strain 66Ms.04 at 108 CFU/mL following the application of black soap (60 g/L) demonstrated the maximum levels of females and nymphs' mortalities with 80 and 91.25%, respectively, after 8 days of treatment. In field conditions, the combined application of the P. koreensis strain 66Ms.04 at 108 CFU/mL with black soap at 60 g/L, for an interval of 7 days, significantly increased the mortality of adult females to 93.33% at 7 days after the second application. These findings showed that the combined treatment of P. koreensis strain 66Ms.04 with black soap can be a potent and eco-friendly pesticide against D. opuntiae.
Hemiptera , Opuntia , Animals , Female , Biological Control Agents , Morocco , Virulence , Soaps , Hemiptera/genetics , Carmine
Sesquiterpenoids constitute the largest subgroup of terpenoids that have numerous applications in pharmaceutical, flavor, and fragrance industries as well as biofuels. Bergamotenes, a type of bicyclic sesquiterpenes, are found in plants, insects, and fungi with α-trans-bergamotene as the most abundant compound. Bergamotenes and their related structures (Bergamotane sesquiterpenoids) have been shown to possess diverse biological activities such as antioxidant, anti-inflammatory, immunosuppressive, cytotoxic, antimicrobial, antidiabetic, and insecticidal effects. However, studies on their biotechnological potential are still limited. This review compiles the characteristics of bergamotenes and their related structures in terms of occurrence, biosynthesis pathways, and biological activities. It further discusses their functionalities and potential applications in pharmaceutical, nutraceuticals, cosmeceuticals, and pest management sectors. This review also opens novel perspectives in identifying and harnessing bergamotenes for pharmaceutical and agricultural purposes.
Mayetiola hordei (Kieffer), known as barley stem gall midge, is one of the most destructive barley pests in many areas around the world, inflicting significant qualitative and quantitative damage to crop production. In this study, we investigate the presence of reproductive symbionts, the effect of geographical origin on the bacterial microbiome's structure, and the diversity associated with natural populations of M. hordei located in four barley-producing areas in Morocco. Wolbachia infection was discovered in 9% of the natural populations using a precise 16S rDNA PCR assay. High-throughput sequencing of the V3-V4 region of the bacterial 16S rRNA gene indicated that the native environments of samples had a substantial environmental impact on the microbiota taxonomic assortment. Briefly, 5 phyla, 7 classes, and 42 genera were identified across all the samples. To our knowledge, this is the first report on the bacterial composition of M. hordei natural populations. The presence of Wolbachia infection may assist in the diagnosis of ideal natural populations, providing a new insight into the employment of Wolbachia in the control of barley midge populations, in the context of the sterile insect technique or other biological control methods.
The wild cochineal Dactylopius opuntiae (Hemiptera: Dactylopiidae) is one of the major insect pests of the prickly pear Opuntia ficus-indica (L.) in Morocco, a well-known fruit and vegetable crop of arid and semi-arid regions around the world. The present study investigated the insecticidal potential of six extracts (three aqueous and three hydroalcoholic (MeOH/H2O, 20/80 (v/v)) from Atriplex halimus (leaves), Salvia rosmarinus (leaves) and Cuminum cyminum (seeds) to control nymphs and adult females of D. opuntiae under laboratory and greenhouse conditions. Out of the tested samples, A. halimus aqueous extract showed the highest activity, inducing mortality rates of 67.04% (after 4 days) and 85% (after 8 days) on nymphs and adult females of D. opuntiae, respectively, at a concentration of 5% under laboratory conditions. It also showed the highest mortality rate of nymphs with 100% (4 days after application) and 83.75% of adult females (7 days after the second application) at a concentration of 5% when combined with black soap at 10 g/L under greenhouse conditions. The difference in the toxicity of plant species of the study was correlated with their saponin content. A total of 36 of these triterpene glucosides were suggested after a comprehensive LC-MSn profiling of the most active extract, A. halimus, in addition to phytoecdysones and glycosylated phenolic acids and flavonoids. These findings provided evidence that the aqueous leaf extract of A. halimus could be incorporated in the management of the wild cochineal as an alternative to chemical insecticides.
The stem borer weevil, Lixus algirus L. (Coleoptera: Curculionidae), causes severe damage to faba beans (Vicia faba L.) in Morocco. A survey was conducted to determine the distribution of L. algirus, its natural enemies, and the severity of damage it causes to faba beans in Morocco. A total of 16 and 27 stops were randomly selected and surveyed in the major faba bean-growing regions during the years 2017 and 2018, respectively. The Gharb region recorded the highest level of L. algirus infestation at 80% and 71.42% in 2017 and 2018, respectively, followed by the Saïs region at 58.75% and 36% in 2017 and 2018, respectively. Two egg parasitoids (Chlorocytuslixi and Anaphes longicornis), one egg predator (Orius sp.), and a larval parasitoid (Cyanopterobracon) were identified. The ectoparasitoid C. lixi was observed to be the most dominant species, with percentages of parasitism in the regions ranging between 35.75% and 70.49%. The larval parasitoid Cyanopterobracon was the second most abundant species, with percentages of parasitism ranging between 3.03% to 15.96%. Understanding the parasitoid complex of L. algirus in Morocco is necessary for the subsequent development of a biological control program.
Pea aphid (Acyrthosiphon pisum Harris) is the major insect pest of lentil in Morocco. We investigated pea aphid mean numbers and yield losses on three lentil varieties at one location during three successive cropping seasons during 2015-2018. The effects of several weather factors on pea aphid population dynamics were investigated. Population density increased in early spring followed by several peaks during March-April and then steeply declined during the late spring. Aphid populations peaked at different times during the three years of the study. In 2016, higher populations occurred during the second and third weeks of April for Abda and Zaria varieties with averages of 27 and 28 aphids/20 twigs, respectively. In 2017, higher populations occurred on the 12th and 13th standard meteorological weeks (SMWs) for Zaria with averages of 24.7 and 27.03 aphids/20 twigs, respectively. In 2018, the population peaked for all varieties at three different times, 11th, 13th, and 17th SMW, with the highest for Zaria being 26.00, 47.41, and 32.33 aphids/20 twigs. Pea aphid population dynamics changed with weather conditions. The number of aphids significantly and positively correlated with maximum temperature, but significantly negatively correlated with relative humidity and wind speed. The minimum temperature and rainfall had non-significant correlations. Pea aphid infestation resulted in losses of total seed weight for all lentil varieties, with the highest avoidable losses for Bakria being 12.51% followed by Zaria with 7.72% and Abda with 4.56%. These losses may justify the development of integrated management options for control of this pest.
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.
