The estimated global production of raspberry from year 2016 to 2020 averaged 846,515 tons. The most common cultivated Rubus spp. is European red raspberry (Rubus idaeus L. subsp. idaeus). Often cultivated for its high nutritional value, the red raspberry (Rubus idaeus) is susceptible to multiple viruses that lead to yield loss. These viruses are transmitted through different mechanisms, of which one is invertebrate vectors. Aphids and nematodes are known to be vectors of specific raspberry viruses. However, there are still other potential raspberry virus vectors that are not well-studied. This review aimed to provide an overview of studies related to this topic. All the known invertebrates feeding on raspberry were summarized. Eight species of aphids and seven species of plant-parasitic nematodes were the only proven raspberry virus vectors. In addition, the eriophyid mite, Phyllocoptes gracilis, has been suggested as the natural vector of raspberry leaf blotch virus based on the current available evidence. Interactions between vector and non-vector herbivore may promote the spread of raspberry viruses. As a conclusion, there are still multiple aspects of this topic that require further studies to get a better understanding of the interactions among the viral pathogens, invertebrate vectors, and non-vectors in the raspberry agroecosystem. Eventually, this will assist in development of better pest management strategies.
Raspberry plants, valued for their fruits, are vulnerable to a range of viruses that adversely affect their yield and quality. Utilizing high-throughput sequencing (HTS), we identified a novel virus, tentatively named raspberry enamovirus 1 (RaEV1), in three distinct raspberry plants. This study provides a comprehensive characterization of RaEV1, focusing on its genomic structure, phylogeny, and possible transmission routes. Analysis of nearly complete genomes from 14 RaEV1 isolates highlighted regions of variance, particularly marked by indel events. The evidence from phylogenetic and sequence analyses supports the classification of RaEV1 as a distinct species within the Enamovirus genus. Among the 289 plant and 168 invertebrate samples analyzed, RaEV1 was detected in 10.4% and 0.4%, respectively. Most detections occurred in plants that were also infected with other common raspberry viruses. The virus was present in both commercial and wild raspberries, indicating the potential of wild plants to act as viral reservoirs. Experiments involving aphids as potential vectors demonstrated their ability to acquire RaEV1 but not to successfully transmit it to plants.
A novel negative-sense single-stranded RNA virus showing genetic similarity to viruses of the genus Rubodvirus has been found in raspberry plants in the Czech Republic and has tentatively been named raspberry rubodvirus 1 (RaRV1). Phylogenetic analysis confirmed its clustering within the group, albeit distantly related to other members. A screening of 679 plant and 168 arthropod samples from the Czech Republic and Norway revealed RaRV1 in 10 raspberry shrubs, one batch of Aphis idaei, and one individual of Orius minutus. Furthermore, a distinct isolate of this virus was found, sharing 95% amino acid identity in both the full nucleoprotein and partial sequence of the RNA-dependent RNA polymerase gene sequences, meeting the species demarcation criteria. This discovery marks the first reported instance of a rubodvirus infecting raspberry plants. Although transmission experiments under experimental conditions were unsuccessful, positive detection of the virus in some insects suggests their potential role as vectors for the virus.
27 June 2024 in Experimental and Applied Acarology
The adoption of the European Green Deal will limit acaricide use in high value crops like raspberry, to be replaced by biological control and other alternative strategies. More basic knowledge on mites in such crops is then necessary, like species, density, and their role as vectors of plant diseases. This study had four aims, focusing on raspberry leaves at northern altitude: (1) identify mite species; (2) study mite population densities; (3) investigate mite intra-plant distribution; (4) investigate co-occurrence of phytophagous mites, raspberry leaf blotch disorder and raspberry leaf blotch virus (RLBV). Four sites in south-eastern Norway were sampled five times. Floricanes from different parts of the sites were collected, taking one leaf from each of the upper, middle, and bottom zones of the cane. Mites were extracted with a washing technique and processed for species identification and RLBV detection. Mites and leaves were tested for RLBV by reverse transcription polymerase chain reaction (RT-PCR) with virus-specific primers. Phytophagous mites, Phyllocoptes gracilis, Tetranychus urticae, and Neotetranychus rubi, and predatory mites, Anystis baccarum and Typhlodromus (Typhlodromus) pyri were identified. All phytophagous mites in cultivated raspberry preferred the upper zone of floricanes, while in non-cultivated raspberry, they preferred the middle zone. The presence of phytophagous mites did not lead to raspberry leaf blotch disorder during this study. RLBV was detected in 1.3% of the sampled plants, none of them with leaf blotch symptoms, and in 4.3% of P. gracilis samples, and in some spider mite samples, implying that Tetranychids could also be vectors of RLBV.
10 May 2024 in Spanish Journal of Agricultural Research
Aim of study: Thrips in raspberry crops are receiving attention in Scandinavian raspberry production because of the increasing sighting of their presence in the flowers. Specific information on thrips species occurring in raspberry and their damage potential is scarce, making thrips management challenging. Therefore, this study aimed to identify thrips in the flowers of cultivated raspberry, Rubus idaeus L., in South Norway. Area of study: Sogndal, Luster and Frogn, Southern Norway Material and methods: Adult thrips were sampled from eight commercial raspberry orchards in the counties Vestland and Viken in June-July 2022. Thrips were mounted using Hoyer’s medium and a total of 213 specimens were morphologically identified. Main results: Five species of thrips were found, Thrips fuscipennis Haliday, Thrips major Uzel, Thrips flavus Schrank, Thrips vulgatissimus Haliday and Thrips brevicornis Priesner. Most specimens were T. flavus, followed by T. fuscipennis and T. vulgatissimus. Research highlights: Among the five species found, only T. fuscipennis has previously been reported in cultivated raspberry, but all five species are associated with flowers of many plants. The findings imply a larger and more geographically varied thrips fauna on raspberry than currently documented. This should be taken into account in future studies on thrips management in raspberry.
Consumers perceive organic vegetables as better in taste and quality compared to conventional vegetables. Therefore, this study aims to determine the sensory difference of choy sum (Brassica chinensis L. var. parachinensis) grown with organic fertiliser and mineral fertiliser without the input of synthetic pesticides. A survey was carried out to determine Malaysian consumer sensory perception on organic and conventional leafy vegetables. The choy sum was planted in a Complete Randomised Block Design (CRBD), with input of organic fertiliser (T1, rate: 1500kg/4046m2) and mineral fertiliser (T2, rate: 63kg/4046m2) in a 7-day interval. It was harvested for sensory evaluation at maturity. Seventy-five untrained panellists were selected for the sensory test. The moisture content was analysed using oven drying method, while the sugar and colour analysis was carried out using a brix refractometer and a spectrophotometer, respectively. The survey confirmed that most consumers believe that the sensory attributes of organic vegetables are better than conventional vegetables. However, sensory evaluation shows that there is no significant difference (P > 0.05) in all sensory attributes tested except for greenness. T2 were significantly greener (P < 0.05) than T1. There were also no significant differences (P > 0.05) found between the treatments in the sugar, moisture and colour analysis.