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

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