Survey and molecular characterization of Hop stunt viroid (HSVd) sequence variants from citrus groves in Morocco

Viroids are the smallest known pathogens of plants. They are single-stranded, circular, rod-like RNAs with no protein capsid no any detectable messenger activity. Citrus is one of the most important commercial fruit crops grown in Morocco. Seven viroids reported to infect Citrus spp. belong to four genera of the family Pospiviroidae. Hop stunt viroid (HSVd) belongs to genus Hostuviroid and consists of a 295-303 nucleotides circular single-stranded RNA. It has been found in a wide range of hosts including several woody and herbaceous crops. Cachexia, an economically important disease of citrus, has been associated with HSVd infection. HSVd isolates are divided into five phylogenetic groups according to the sequence variants: plum-type, hop-type, citrus-type, plum-citrus-type and plum-hop-citrus-type. In this work we present the molecular characterization of six new sequence variants of HSVd obtained from the main Moroccan citrus growing areas: Gharb, Haouz, Loukkos, Moulouya, Souss and Tadla, respectively. The genetic diversity among the Moroccan variants was investigated. Phylogenetic analysis showed that Moroccan citrus HSVd variants were clustered into one group within the citrus-type and the sequence variability seems neither related to the host nor to symptomatology. Despite an accumulation of nucleotide changes, the secondary structure of the viroid mol­ecule was conserved. Since citrus viroids are readily mechanically transmissible via working tools, they affect both old and young plantings in all the citrus groves surveyed. Keywords: Hop stund viroid, Survey, Molecular characterization, Morocc

Certification scheme for fig plants (Ficus carica L.) in Morocco

Le programme de certification et d’assainissement des plants de figuier ont pour objectif la production des plants dont l’authenticité variétale est reconnue,  indemnes de virus et d’autres pathogènes. Au Maroc, ce système de certification comprend des indications détaillées sur la production des plants de figuier à multiplication végétative. L’organisation de la certification dans ses différentes étapes est détaillée, les organismes sollicités et le contrôle sanitaire garantissant des plants certifiés indemnes de maladies virales causant la mosaïque du figuier sont décrits. Ce programme implique les secteurs de la recherche, les institutions publiques, les sociétés privées, les pépiniéristes Marocains, afin de mettre en place un système de certification phytosanitaire du figuier. Mots-clés: Figuier, certification, virus, authenticité variétale, Maroc.  Certification and sanitation programs for pathogen-tested material of the fig tree have the aim of providing plants that are true-to-type, free from virus and substantially free from other pests. In Morocco, this certification scheme provides detailed guidance on the production of vegetative propagated fig plants. The organization of certification through its steps is detailed and the agencies involved in the sanitary controls, which guarantee the freedom of certified stocks from virus causing mosaic on fig plants are described. This program involves the sectors of research, public institutions and Moroccan nurseries in order to set up a system of sanitary certification of fig tree in Morocco. Keywords: Fig plants, certification, virus, trueness-to-type, Morocco

Key fruit flies species (Diptera, Tephritidae) reported in Africa and presenting a biosecurity concern in Morocco: An Overview

Fruit crop species are from the most widely cultivated crops in Morocco. However, the sustainability of this lucrative business is threatened by infestations of invasive fruit flies (Diptera: Tephritidae) that may inflict heavy economic losses to the country if their invasion occurs. At this time, Medfly is the main fruit fly which causes a high loss and is a phytosanitary concern to fruit species. The distribution and abundance of the major frugivorous tephritids are influenced by host presence, climatic factors, and their potential of invasion. Two types of economic impact of fruit flies are distinguished, direct losses in the yield and indirect losses due to the loss of markets caused by quarantine restrictions imposed by importing countries to prevent the entry of exotic flies in their territory. The most important invasive tephritid fruit flies present in Africa and that may constitute a risk of invasion into Morocco are Bactrocera dorsalis, Bactrocera zonata and Bactrocera cucurbitae. Also, the indigenous species within genera Ceratitis ((Ceratitis quinaria, C. anonae, C. catoirii, C. cosyra, C. silvestrii, C. ditissima, C. fasciventris, C. rosa, C. quilicii) and Dacus (Dacus latifrons, D.vertebratus, D.bivittatus, D.punctatifrons,  Dacus ciliates) may present a risk of introduction to Morocco. These fruit fly species are characterized by having a wide range of host plants and a wide distribution throughout Africa. The risk of spread is enhanced by the lack of control and the weakness of the identification process of the present and newly introduced species. This review presents the status and the distribution of major fruit fly species present in Africa, gives an overview of their host plants, new invasions and means of detection and phytosanitary measures to implement in Morocco to avoid any invasion originated from other African countries. Keywords: Africa, Fruit fly, Distribution, host plant, Invasion, biosecurity, and Morocco

Incidence of Citrus exocortis viroid and Hop stund viroid in commercial citrus groves from Morocco

Viroids are the smallest known pathogens of plants. They are single-stranded, circular, rod-like RNAs with no protein capsid nor any detectable messenger activity. Citrus species are natural hosts of at least seven viroids of the Pospiviroidae family. Exocortis and cachexia are the most important viroid diseases of citrus in Morocco. In order to assess the incidence and distribution of Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd), extensive surveys were conducted, between 2008 and 2018, in the main citrus growing areas of the country. A total of 100 commercial citrus groves of different varieties were inspected for symptoms of exocortis and cachexia, and 5390 samples were collected for laboratory analyses, using imprint hybridization. Representative positive and negative samples for each viroid were selected and submitted for additional confirmatory RT-PCR assays using specific primers. The incidence of infection by viroids was about 29.0 %, regardless of citrus species and location, although a slightly higher number of infected trees were located in the Gharb region (41.5 %). CEVd was detected in 11.3 -18.2% of the tested samples, while HSVd was detected up to 10.8 % of the samples tested. Since CEVd and HSVd are readily mechanically transmissible via working tools, they affect both old and young plantings in all the surveyed regions. Key words: Citrus exocortis viroid, Hop stunt viroid, citrus, survey, Morocc

Effect of proximity to Jujube (Ziziphus lotus and Ziziphus jujube) trees on medfly (Ceratitis capitata) populations in citrus orchards of Moulouya Perimeter

Moulouya Perimeter is one of the most important zones of Citrus production in Morocco, with an area of 22.000 ha and 360.000 tons of Citrus production. Medfly “Ceratitis capitata, Wiedemann 1824” is a pest with an important economic impact for Citrus, because of its impact on yield losses and phytosanitary concern linked to its presence. In Citrus orchards of Moulouya perimeter, adjacent wild jujube (Ziziphus lotus and Ziziphus jujuba) trees may have an impact on Medfly populations. The main objective of this study is to evaluate the influence of adjacent jujube trees, growing in windbreaks and noncommercial orchards, on medfly captures in the traps located in citrus orchards and to determine the amount of increase of punctured fruits caused by medfly oviposition considering the distance ranges to the jujube trees (10, 25, 50, 75, 100, 125, 150, 175, 200, 225, 250 and 275m).To achieve this purpose, 180 traps were placed in 15 orchards and monitored for medfly captures weekly, from April to November 2019, within three locations (Aklim, Chouihia, and Reggada) representing Citrus producing area of Moulouya Perimeter. The monitoring of C. capitata adults was conducted using “Maghreb med” traps with trimedlure (tbutyl-4(or5)-chloro-2-methyl-cyclohexane carboxylate) male-specific para-pheromone as attractant and dichlorvos as a toxicant. Five orchards per each location were selected and 12 traps were hung in every orchard in fixed distances from the jujube trees and fruits were checked for punctures. The influence of each jujube tree in citrus orchards in his vicinity is higher within distances inferior to 75 m. Then, its impact could approach 2,25 Ha on average, and in this area, C. capitata population densities were twice to five times as high as in other distances. Furthermore, Citrus trees located at distances inferior to 75m from the jujube trees showed an increase in the percentage of punctured fruits compared with distances higher than 75m

Assessment of the main causes of sorting gaps in the Citrus packinghouses of Berkane, Morocco

Sorting gaps are one of the main challenges that the Citrus industry is facing worldwide. In Morocco, the rates of sorting gaps reach levels exceeding 40% on average. In Berkane area, the rate of Clementine sorting gaps in packinghouses is an important concern to exporters and their characterization is not well studied. The present study covered five clementine packinghouses of Berkane area out of the 20 packinghouses inventoried in the zone during the 2019/2020 export campaign between October 20th, 2019, and January 20th, 2020. In each packinghouse, the sorting gaps were examined and characterized to separate the different categories of sorting gaps types and determine the sorting gaps rate. The objective of this study is to characterize the frequent causes of Clementine sorting gaps and analyze the effect of the packing period on the importance of the rate of different types of causes of sorting gaps. Also, the evolution of gap rates at the station level was analyzed to show the similarities and differences between the overall sorting gaps rates and the sorting gaps rates by type of defects per packinghouse. Results showed an average of sorting gaps rates of about 38.4% of total Clementine fruit received in packinghouses. Depending on the packaging period, the rates of sorting gaps varied from one packinghouse to another and from one type of gaps to another. The gaps caused by insects presented high levels in the area and at all Berkane studied packinghouses. Fruits processed in the period from October 20th to November 20th, 2019 recorded a very high rate of sorting gaps with 44.5% followed by the period from December 20th, 2019 to January 20th, 2020 with a rate of 40% and the period from October 20th to November 20th, 2019 with 31%. In quest of conceiving strategies to reduce Sorting gaps rates, it is of utmost importance to understand the main factors influencing these rates in all Clementine handling and producing stages. Keywords: Sorting gap, Citrus fruits, Packinghouse, Causes, Berkane

A preliminary survey on the presence of Xylella fastidiosa in olive, citrus and grapevine groves in Morocco

Xylella fastidiosa, bactérie gram-négative, confinée au xylème, très polyphage, provoque diverses maladies sur plus de 300 plantes hôtes. Compte tenu de la récente détection confirmée de X. fastidiosa dans l'Union Européenne, cette bactérie est en train de devenir une menace sérieuse pour le secteur agricole marocain. Une enquête a été menée durant Mai-Septembre 2015 sur la présence de X. fastidiosa dans plusieurs plantations de l'olivier, des agrumes et de la vigne à  travers le pays. Des symptômes sévères qui pourraient être associés à  la bactérie ont été relevés. Un total de 900 échantillons de différentes cultures à  partir de différentes régions ont été collectés au hasard: 220 oliviers (cv. Picholine Marocaine) de deux régions, 410 arbres d'agrumes appartenant à  7 cultivars collectés dans 4 régions et 270 plants de vigne appartenant à  6 cultivars de 3 régions; tous ces échantillons ont été testés pour la présence de X. fastidiosa en utilisant un kit commercial ELISA. Les résultats obtenus ne montrent aucun échantillon positif. Ces résultats préliminaires sont considérés comme une bonne première indication, étant donné que X. fastidiosa n'a pas été détectée au Maroc. Cependant, des enquêtes continues à  grande échelle sont nécessaires pour empêcher son entrée dans le pays. Mots-clés: Maroc, Xylella fastidiosa, enquête, Olivier, agrumes, vigne, ELISA.The bacterium Xylella fastidiosa is gram negative, xylem-inhabiting, devastating pathogen which causes various diseases on more than 300 plant hosts. Given the recent confirmed findings of  X. fastidiosa in the European Union, this bacterium is becoming a serious threat to the Moroccan agricultural sector. A survey was conducted during May-September 2015 on the presence of X. fastidiosa in several commercial groves, covering olive, citrus and grapevine growing areas. In a few trees, severe symptoms which could be associated to the bacterium were observed. A total of 900 samples of different crops from different regions were randomly collected: 220 olive trees (cv. Picholine Marocaine) from two regions, 410 citrus trees belonging to 7 different cultivars collected in 4 regions and 270 grapevine plants belonging to 6 different cultivars from 3 regions; all these samples were tested for the presence of X. fastidiosa by using an ELISA commercial kit. The obtained results did not show any positive sample. These preliminary results are taken as an encouraging indication, considering that X. fastidiosa was not found in Morocco, at least in the surveyed crops. However, frequent extensive surveys in different regions are needed to prevent its entrance into the country. Keywords: Morocco, Xylella fastidiosa, survey, olive, citrus, grapevine, ELISA

Molecular characterization of Beet necrotic yellow vein virus (BNYVV) infecting sugar beet in Tadla

Sugar beet is the most important sugar crop in Morocco. The main production areas of sugar beet are Doukkala, Tadla, Gharb, and Moulouya. Rhizomania, caused by Beet necrotic yellow vein virus (BNYVV, genus Benyvirus), was first described in Italy and has spread in most sugar beet-growing areas of the world within a few decades. In the Tadla region, Rhizomania is one of the major phytosanitary problems for the sugar-beet industry. In 2010, five isolates from different locations in the Tadla region were collected for molecular characterization studies by sequencing the coat protein gene (CPg). The obtained results showed that all the sequenced isolates were in the B type of BNYVV and revealed the highest nucleotide similarity with the Belgian isolate B2 (AY696077), with a sequence homology of 100%. To the best of our knowledge, this is the first molecular characterization of BNYVV isolates in Morocco

Caractérisation moléculaire du virus des nervures jaunes nécrotiques de la betterave (BNYVV) infectant la betterave à sucre au Tadla

La betterave sucrière est la principale source de sucre au Maroc. Les principales zones de production de la betterave à  sucre sont Doukkala, Tadla, Gharb, et Moulouya. La rhizomanie, causée par le virus des nervures jaunes nécrotiques de la betterave (BNYVV, genre Benyvirus), a été décrite pour la première fois en Italie et s'est propagée dans la plupart des régions productrices de la betterave sucrière. Dans la région de Tadla, la rhizomanie est l'un des principaux problèmes phytosanitaires majeurs pour la culture de la betterave sucrière. En 2010, cinq isolats de différentes localités de la région de Tadla ont été collectés pour des études de caractérisation moléculaire par le séquençage du gène de protéine de la capside (CP). Les résultats obtenus ont montré que les isolats marocains étaient dans le groupe B de BNYVV; ces isolats ont montré une grande similarité nucléotidique avec l'isolat Belge B2 (AY696077), avec une homologie de séquence de 100 %. Au mieux de nos connaissances, il s'agit de la première caractérisation moléculaire des isolats de BNYVV au Maroc. Mots-clés: Rhizomanie, betterave sucrière, caractérisation moléculaire, gène de la protéine de la capside, Maroc.Sugar beet is the most important sugar crop in Morocco. The main production areas of sugar beet are Doukkala, Tadla, Gharb, and Moulouya. Rhizomania, caused by Beet necrotic yellow vein virus (BNYVV, genus Benyvirus), was first described in Italy and has spread in most sugar beet-growing areas of the world within a few decades. In the Tadla region, Rhizomania is one of the major phytosanitary problems for the sugar-beet industry. In 2010, five isolates from different locations in the Tadla region were collected for molecular characterization studies by sequencing the coat protein gene (CPg). The obtained results showed that all the sequenced isolates were in the B type of BNYVV and revealed the highest nucleotide similarity with the Belgian isolate B2 (AY696077), with a sequence homology of 100 %. To the best of our knowledge, this is the first molecular characterization of BNYVV isolates in Morocco. Keywords: Rhizomania, sugar beet, molecular characterization, coat protein gene, Morocco

A preliminary survey on the presence of Xylella fastidiosa in olive, citrus and grapevine groves in Morocco

The bacterium Xylella fastidiosa is gram negative, xylem-inhabiting, devastating pathogen which causes various diseases on more than 300 plant hosts. Given the recent confirmed findings of X. fastidiosa in the European Union, this bacterium is becoming a serious threat to the Moroccan agricultural sector. A survey was conducted during May-September 2015 on the presence of X. fastidiosa in several commercial groves, covering olive, citrus and grapevine growing areas. In a few trees, severe symptoms which could be associated to the bacterium were observed. A total of 900 samples of different crops from different regions were randomly collected: 220 olive trees (cv. Picholine Marocaine) from two regions, 410 citrus trees belonging to 7 different cultivars collected in 4 regions and 270 grapevine plants belonging to 6 different cultivars from 3 regions; all these samples were tested for the presence of X. fastidiosa by using an ELISA commercial kit. The obtained results did not show any positive sample. These preliminary results are taken as an encouraging indication, considering that X. fastidiosa was not found in Morocco, at least in the surveyed crops. However, frequent extensive surveys in different regions are needed to prevent its entrance into the country