Sanitary selection of four virus-tested fig (Ficus carica L.) cultivars in Morocco

Fig (Ficus carica L.), a fruit tree widely grown in Morocco, is affected to a very large extent by fig mosaic disease (FMD), a complex with which eight viruses of different taxonomic position are associated. In order to select virus-free fig cultivars in Morocco, field surveys were conducted, between 2014 and 2018, in 11 different commercial orchards located in four regions (Azilal, El Jadida, Moulay Driss Zarhoune and Taounate). A total of 44 leaf samples representing 11 fig cultivars, without FMD symptoms, were prospected and collected for laboratory analyses. Total nucleic acids were extracted from leaf veins and tested by PCR for the presence of FMV, FLMaV-1, FLMaV-2, FMMaV, FLV-1, FBV-1, FFkaV and FCrV using specific primers. Among the 11 tested cultivars, only four (Chetoui, Rhoudane, Elquoti Lebied and Embar Lekhel) were free from the tested viruses. This study allowed the identification of at least one “virus-tested” candidate clone from four different fig cultivars which can represent the potential mother plants for propagating materials in order to establish new fig nurseries and orchards. Keywords: Fig, sanitary selection, viruses, Morocco

Fig tree viruses in Morocco

Fig (Ficus carica L.), widely grown in Morocco, is an important fruit crop for the country, both economically and socially. Fig mosaic disease is a complex with which at least eight viruses of different taxonomic position are associated. In 2014-2018, field surveys for viruses were carried out in the main fig growing areas of Morocco (Azilal, El Jadida, Moulay Driss Zarhoune and Taounate). A total of 117 samples were collected and checked by reverse transcription polymerase chain reaction (RT-PCR), using virus specific primers, for the presence of Fig mosaic virus (FMV), Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig latent virus 1 (FLV-1), Fig fleck-associated virus (FFkaV) and Fig cryptic virus (FCrV). PCR was also carried out for the presence of Fig badnavirus 1 (FBaV-1). About 71% of the trees were infected with at least one virus, with mixed infections in ca. 50% of the samples. FMV was the prevailing virus (40.9% infection), especially in Azilal (47.4%) and on cv. Nabout (46.2%), followed by FLMaV-1 (30.7%). FMMaV-2, FMMaV, FFkaV and FBV-1 were detected in 25.2%, 25.2%, 8.7% and 5.5% of the samples, respectively. FLV-1 and FCrV were not found. This is the first report on the presence of FMV, FLMaV-1, FLMaV-2, FMMaV, FFkaV and FBV-1 in Morocco and offers a preliminary insight into the unsatisfactory health status of fig trees in the country. Considering that the production of figs in Morocco is increasing, more attention should be given to improving the phytosanitary condition of fig trees in the country. Keywords: Ficus carica, RT-PCR, virus detection, fig mosaic, Morocc

Preliminary evaluation of the status of olive-infecting viruses in Morocco

Olive is one of the most ancient and important fruit tree crops in Morocco. Olive trees are affected by at least 15 viruses belonging to eight genera. Most of these viruses were isolated from symptomless trees and/or reported in a very limited number of trees. In order to check for the presence of olive-infecting viruses in Morocco, a preliminary survey was conducted during March-April 2014 and a total of 105 samples (cv. Picholine marocaine) were randomly collected from 15 commercial orchards located in three important olive-growing regions: Béni Mellal, Marrakech and Meknès. Samples were tested by RT-PCR, using specific primers, to search for the presence of eight olive viruses: Olive latent virus 1 (OLV-1), Olive latent virus 2 (OLV-2), Strawberry latent ringspot virus (SLRSV), Cucumber mosaic virus (CMV), Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Olive latent ringspot virus (OLRSV) and Olive leaf yellowing-associated virus (OLYaV). About one third (34.3%) of the trees were infected. In particular, the closterovirus OLYaV was the most widespread, as it was detected in 16.2% of the samples, followed by the necrovirus OLV-1 (8.6%), the oleavirus OLV-2 (3.8%), the cucumovirus CMV (2.8%), the sadwavirus SLRV (1.9%), and the nepovirus ArMV (0.9%). The fact that these infections are mostly latent and the increasing of national demand for propagation material of high sanitary standard call for the implementation of a cleanup using both heat therapy and in vitro propagation for the establishment of olive foundation blocks. Key-words: Olive trees, olive-infecting viruses, Morocc

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

The Occurrence of Major Viruses Infecting Zucchini Squash (Cucurbita pepo L.) in Morocco

Zucchini squash, Cucurbita pepo L., is one of the most economically important vegetable crops in Morocco. Virus diseases are a major factor in limiting production of zucchini squash in the country. During the growing seasons 2015, 2016 and 2017, the main areas of field-grown cucurbit production in Morocco (Loukkos, Gharb, Bouznika, Doukkala and Souss) were surveyed for the occurrence and distribution of viruses of zucchini squash. A total of 38 commercial fields were visited and inspected for symptoms of virus diseases and 415 leaf samples were collected from plants showing virus-like symptoms for laboratory analyses. ELISA technique was used to detect the following viruses: Zucchini yellow mosaic virus (ZYMV), Squash mosaic virus (SqMV), Cucumber mosaic virus (CMV), Papaya ringspot virus-watermelon strain (PRSV-W) and Cucurbit aphid-borne yellows virus (CABYV). The obtained results showed that virus diseases were widely distributed in the country with an infection rate of 77.6%, especially in the region of Loukkos where 85% of the tested plants were infected by at least one virus. To the best of our knowledge, this isthe first study on the occurrence and geographical distribution of viruses infecting zucchini squash in Morocco. This study provides valuable information, which could be beneficial and of great interest for the researchers, growers and the plant protection services for planning future strategies to control virus diseases of zucchini squash in 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

First report on the occurence of grapevine rupestris stem pitting-associated virus in Moroccan grapevines

n/

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

CONTRIBUTION TO THE KNOWLEDGE OF APHROPHORID SPITTLEBUGS (HEMIPTERA: APHROPHORIDAE) FROM MOROCCO

This paper lists the current fauna of Aphrophoridae family in Morocco. Distribution data of their occurrence in the country are provided. Nine species of aphrophorid spittlebugs found in Morocco are listed, five of them identified and described for the first time in the country and four other species reported in the literature. An identification key of aphrophorid genera and species is given. The Mediterranean spittlebug Philaenus tesselatus Melichar, 1899 (Moroccan specimen) is described and differentiated from the European meadow spittlebug Philaenus spumarius Linnaeus, 1758 (Italian specimen). The newly reported Philaenus sp. specimen found in Morocco is described