A study of Hessian fly, Mayetiola destructor (Say), biotypes and resistance in wheats in Morocco

Call number: LD2668 .T4 1986 E42Master of ScienceEntomolog

Cloning, Expression, Sequence Analysis and Homology Modeling of the Prolyl Endoprotease from Eurygaster integriceps Puton

Eurygaster integriceps Puton, commonly known as sunn pest, is a major pest of wheat in Northern Africa, the Middle East and Eastern Europe. This insect injects a prolyl endoprotease into the wheat, destroying the gluten. The purpose of this study was to clone the full length cDNA of the sunn pest prolyl endoprotease (spPEP) for expression in E. coli and to compare the amino acid sequence of the enzyme to other known PEPs in both phylogeny and potential tertiary structure. Sequence analysis shows that the 5ꞌ UTR contains several putative transcription factor binding sites for transcription factors known to be expressed in Drosophila that might be useful targets for inhibition of the enzyme. The spPEP was first identified as a prolyl endoprotease by Darkoh et al., 2010. The enzyme is a unique serine protease of the S9A family by way of its substrate recognition of the gluten proteins, which are greater than 30 kD in size. At 51% maximum identity to known PEPs, homology modeling using SWISS-MODEL, the porcine brain PEP (PDB: 2XWD) was selected in the database of known PEP structures, resulting in a predicted tertiary structure 99% identical to the porcine brain PEP structure. A Km for the recombinant spPEP was determined to be 210 ± 53 µM for the zGly-Pro-pNA substrate in 0.025 M ethanolamine, pH 8.5, containing 0.1 M NaCl at 37 °C with a turnover rate of 172 ± 47 µM Gly-Pro-pNA/s/µM of enzyme

Ennemis naturels associés à Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae) au Maroc et leurs fluctuations démographiques

Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae) is the most important pest of prickly pear cactus Opuntia ficus-indica in Morocco in recent years. In order to identify the natural enemies associated with this pest, and determine their population fluctuations, samplings were carried out at two distinct areas, sampling area 1- Zemamra in the Sidi Bennour region (120 km north-west of Marrakech), Morocco and sampling area 2-Gharbia in the same region. 15 species were found and identified: Episyrphus balteatus de Geer, Eupeodes corollae Fabricius (Diptera: Syrphidae), Hyperaspis campestris (Herbst, 1783), Scymnus interruptus (Goeze). Scymnus loewii, Nephus redtenbacheri (Mulsant, 1846), Scymnus latemaculatus, Scymnus guttulatus LeConte, Exochomus nigripennis (Erichson, 1843), Coccinella septempunctata (Linnaeus, 1758), Hippodamia convergens, Chilocorus bipustulatus (Linnaeus, 1758), and Chilocorus politus (Mulsant, 1850) (Coleoptera: Coccinellidae) and Emmelina Monodactyla (Lepidoptera: Pterophoridae). Hyperaspis campestris was found to be the most important specie associated with D. opuntiae in study area-1 and Chilocorus bipustulatus in study area-2. Keywords:  Dactylopius opuntiae, Hyperaspis campestris, Chilocorus bipustulatus, biocontrolDactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae) est le principal ravageur du cactus Opuntia ficus-indica, au Maroc, ces dernières années. Afin d'identifier les ennemis naturels associés à cet insecte nuisible et de déterminer leurs fluctuations démographiques,des échantillonnages ont été effectués dans deux zones distinctes durant deux années 2017- 2018, la zone d'échantillonnage 1- Zemamra dans la région de Sidi Bennour (120 km au nord-ouest de Marrakech), au Maroc et zone d'échantillonnage  2- Gharbia localité dans la même région. 15 espèces ont été trouvées et identifiées: Episyrphus balteatus de Geer,  Eupeodes corollae Fabricius (Diptera: Syrphidae), Hyperaspis campestris (Herbst, 1783), Scymnus interruptus (Goeze). Scymnus loewii, Nephus redtenbacheri (Mulsant, 1846), Scymnus latemaculatus, Scymnus guttulatus LeConte, Exochomus nigripennis (Erichson, 1843), Coccinella septempunctata (Linnaeus, 1758), Hippodamia convergens, Chilocorus bipustulatus (Linnaeus, 1758), and Chilocorus politus (Mulsant, 1850).  (Coleoptera: Coccinellidae), and Emmelina Monodactyla (Lepidoptera: Pterophoridae). Hyperaspis campestris s'est révélé être l'espèce la plus importante associée à D. opuntiae dans la zone d'étude 1 et à Chilocorus bipustulatus dans la zone d'étude 2. Mots-clés: Dactylopius opuntiae, Hyperaspis campestris, Chilocorus bipustulatus, biocontrôl

Wheat breeding for Hessian fly resistance at ICARDA

Hessian fly (HF), Mayetiola destructor (Say) is an important pest of wheat in North Africa, North America, Southern Europe, Northern Kazakhstan, Northwestern China, and New Zealand. It can cause up to 30% yield losses and sometimes can result in complete crop failure if infestation coincides with young stage of the wheat crop. Studies to-date have shown the availability of genetic diversity in the wheat genetic resources (landraces, wild relatives, cultivars, etc.) for resistance to Hessian fly. About 37 resistance genes have been reported from these wheat genetic resources for resistance to Hessian fly, of which, some have been deployed singly or in combination in the breeding programs to develop high yielding varieties with resistance to HF. Deployment of resistant varieties in different agro-ecologies with other integrated management measures plays key role for the control of HF. This paper summarizes the importance, life cycle, mechanisms of resistance, gene mining, and wheat breeding efforts for HF resistance

Genome-Wide Association Study for Multiple Biotic Stress Resistance in Synthetic Hexaploid Wheat

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to overcome previously identified resistance genes. A total of 125 synthetic hexaploid wheats (SHWs; 2n = 6x = 42, AABBDD, Triticum aestivum L.) were characterized for resistance to fungal pathogens that cause wheat rusts (leaf; Puccinia triticina, stem; P. graminis f.sp. tritici, and stripe; P. striiformis f.sp. tritici) and crown rot (Fusarium spp.); cereal cyst nematode (Heterodera spp.); and Hessian fly (Mayetiola destructor). A wide range of genetic variation was observed among SHWs for multiple (two to five) biotic stresses and 17 SHWs that were resistant to more than two stresses. The genomic regions and potential candidate genes conferring resistance to these biotic stresses were identified from a genome-wide association study (GWAS). This GWAS study identified 124 significant marker-trait associations (MTAs) for multiple biotic stresses and 33 of these were found within genes. Furthermore, 16 of the 33 MTAs present within genes had annotations suggesting their potential role in disease resistance. These results will be valuable for pyramiding novel genes/genomic regions conferring resistance to multiple biotic stresses from SHWs into elite bread wheat cultivars and providing further insights on a wide range of stress resistance in wheat

The Chickpea Pod Borer, <i>Helicoverpa armigera</i> (Hübner): Yield Loss Estimation and Biorational Insecticide Assessment in Morocco

Helicoverpa armigera (Hübner) is considered one of the most destructive insect pests of chickpea crops in Morocco; however, the extent of the yield loss it causes in Morocco is unknown. This study assessed the yield losses and pod damage caused by the chickpea pod borer H. armigera on four improved Kabuli varieties with insecticide treatment at two different locations. The second part of this study investigated the contact and systemic toxicity of different biological and selective insecticides in the control of the larvae of H. armigera under controlled laboratory and field conditions. The results demonstrated that the yield losses due to H. armigera infestation were in the range of 14.3–31.2%. Chickpea pod borer infestation resulted in losses in the total seed weight for all the chickpea varieties, with the highest yield losses for Zahor (F84-145C) being 31.18% at Allal Tazi followed by Farihane (F84-79C) with 27.38% at the Marchouch station. Emamectin benzoate at 250 g/ha showed a high level of larvicidal and systemic activity, with 100% mortality 24 h after application. Indoxacarb at 25 mL/100 L water, recorded 100% and 92% larval mortality in larvicidal and systemic activity, 48 h after application, respectively. The bioinsecticide spinosad in 30 mL/100 L water resulted in 88% and 92% larval mortality in contact and systemic activity, 48 h after application, respectively. Under field conditions, the two insecticides emamectin benzoate and indoxacarb were found to be highly effective in reducing the H. armigera larval population and pod damage after two sprays. Both insecticide treatments significantly increased grain yields compared with the untreated plots, with 25.8% and 24.5%, respectively. These findings showed that two applications of the selective chemical insecticides emamectin benzoate or indoxacarb with a week interval starting from the pod setting could be incorporated into the management strategies for the control of H. armigera

Population Dynamics and Yield Loss Assessment for Pea Aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), on Lentil in Morocco

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&ndash;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&ndash;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

Exploratory Survey of <i>Lixus algirus</i> L. (Coleoptera: Curculionidae) and Its Natural Enemies in Morocco

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

Potentiel de prédation et préférence alimentaire de Cryptolaemus montrouzieri sur Dactylopius opuntiae en laboratoire

Recently the introduced mealybug, Dactylopius opuntiae, has been the most devastating insect of cactus in Morocco. The cochineal has spread to many regions of the kingdom and caused enormous socio-economic and environmental losses. To control this menace, predatory potential of Cryptolaemus montrouzieri was investigated under laboratory conditions at 26±2°C, 60±10% RH and 12:12 h L:D regime. In this study, the experiments were conducted in choice feeding tests (D. opuntiae second instar, first instar nymphs and eggs were offered simultaneously). C. montrouzieri adults and fourth instar larvae were the most feeders’ predators on different stages of D. opuntiae. Manly’s preference index values showed that all predator stages preferred younger stages of mealybug (p &lt; 0.5), (negative switching). Furthermore, studies on development time showed that egg, larvae, prepupal, pupal and adult stages duration were 3.60±0.67, 4.05±0.90, 4.45±0.85, 5.48±0.91, 8.15±0.36, 1.48±0.60, 10.80±0.65, and 103.28±2.37, respectively. The results of this study showed that C. montrouzieri has the ability to be exploited as a predator of D. opuntiae in Morocco. Keywords:&nbsp; Dactylopius opuntiae, Cryptolaemus montrouzieri, Opuntia ficus-indica, biological control, MoroccoRécemment, la cochenille à carmin introduite, Dactylopius opuntiae, est l'insecte le plus dévastateur du cactus au Maroc. La cochenille s'est étendue à de nombreuses régions du royaume et a provoqué d'énormes pertes socio-économiques et environnementales. Pour contrôler cette menace, le potentiel prédateur de Cryptolaemus montrouzieri a été étudié en laboratoire à une température de 26±2 °C, 60±10% HR et 12:12 h L: D. Dans cette étude, les expériences ont été menées dans le cadre d’essais d’alimentation en choix (nymphes de deuxième stade, nymphes de premier stade et les œufs de D. opuntiae offerts simultanément au prédateurs). Les adultes de C. montrouzieri et les larves de quatrième stade étaient les prédateurs les plus nourris à différents stades de D. opuntiae. Les valeurs de l'indice de préférence de Manly ont montré que tous les stades prédateurs préféraient les stades plus jeunes de la cochenille (p &lt;0.5) (commutation négative). En outre, des études sur le temps de développement ont montré que les œufs, les larves, La durée des phases prépupale, pupal et adulte était de 3.60±0.67, 4.05±0.90, 4.45±0.85, 5.48±0.91, 8.15±0.36, 1.48±0.60, 10.80±0.65 et 103.28±2.37, respectivement. Les résultats de cette étude ont montré que C. montrouzieri pouvait être exploité comme prédateur de D. opuntiae au Maroc. Mots-clés: Dactylopius opuntiae, Cryptolaemus montrouzieri, Opuntia &nbsp;ficus-indica, contrôle biologique, Maro

Deep sequencing and genome-wide analysis reveals the expansion of MicroRNA genes in the gall midge \u3ci\u3eMayetiola destructor\u3c/i\u3e

Background: MicroRNAs (miRNAs) are small non-coding RNAs that play critical roles in regulating post transcriptional gene expression. Gall midges encompass a large group of insects that are of economic importance and also possess fascinating biological traits. The gall midge Mayetiola destructor, commonly known as the Hessian fly, is a destructive pest of wheat and model organism for studying gall midge biology and insect – host plant interactions. Results: In this study, we systematically analyzed miRNAs from the Hessian fly. Deep-sequencing a Hessian fly larval transcriptome led to the identification of 89 miRNA species that are either identical or very similar to known miRNAs from other insects, and 184 novel miRNAs that have not been reported from other species. A genomewide search through a draft Hessian fly genome sequence identified a total of 611 putative miRNA-encoding genes based on sequence similarity and the existence of a stem-loop structure for miRNA precursors. Analysis of the 611 putative genes revealed a striking feature: the dramatic expansion of several miRNA gene families. The largest family contained 91 genes that encoded 20 different miRNAs. Microarray analyses revealed the expression of miRNA genes was strictly regulated during Hessian fly larval development and abundance of many miRNA genes were affected by host genotypes. Conclusion: The identification of a large number of miRNAs for the first time from a gall midge provides a foundation for further studies of miRNA functions in gall midge biology and behavior. The dramatic expansion of identical or similar miRNAs provides a unique system to study functional relations among miRNA iso-genes as well as changes in sequence specificity due to small changes in miRNAs and in their mRNA targets. These results may also facilitate the identification of miRNA genes for potential pest control through transgenic approaches