Tomato is the most economically important fruit/vegetable crop grown worldwide. However, viral diseases remain an important factor limiting its productivity, with estimated quantitative and qualitative yield losses in tomato crops often reaching up to 100%. Many viruses infecting tomato have been reported, while new viral diseases have also emerged. The climatic changes the world is experiencing can be a contributing factor to the successful spread of newly emerging viruses, as well as the establishment of disease in areas that were previously either unfavourable or where the disease was absent. Because antiviral products are not available, strategies to mitigate viral diseases rely on genetic resistance/tolerance to infection, control of vectors, improvement in crop hygiene, roguing of infected plants and seed certification. Tomato brown rugose fruit virus (ToBRFV) is an emerging viral threat to tomato productivity and is currently spreading into new areas, which is of great concern to the growing global production in the absence of mitigation measures. This review presents the current knowledge about ToBRFV and future prospects for an improved understanding of the virus, which will be needed to support effective control and mitigation of the impact it is likely to cause.

Potato affecting viruses is an important biotic factor that hampers both the quality and yield of potato production worldwide. The occurrence of potato viruses has been historically recorded in India. Viruses such as potato virus X (PVX), potato virus Y (PVY), potato virus A (PVA), potato virus M (PVM), potato virus S (PVS), potato leafroll virus (PLRV) have been recorded in all potato growing zones. To investigate the presence and distribution of potato virus diseases in North‐East India, a survey of seven major potato growing regions was conducted during the 2017 and 2018 growing seasons. The presence of potato viruses was confirmed by double antibody sandwich ELISA (DAS‐ELISA) with reverse transcriptase polymerase chain reaction (RT‐PCR) performed on selected samples. The sequencing followed by annotation of PCR amplicons obtained from RT‐PCR showed 95–100% nucleotide sequence identities with respective virus accessions on NCBI GenBank. The multiple sequence analysis and phylogenetic studies provided an overview of the genetic diversity pattern among different potato virus isolates. This study reveals a broad picture of the potato virus infections occurring in Northeastern states of India, which may be useful to develop effective control strategies against the potato viruses.

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Cucurbits are economic crops in Nigeria which serve as additional nutritional supplements and also good sources of income for farmers. Viral diseases are a worldwide problem of cucurbits and a major limiting factor for cucurbit production. A survey of farmer’s fields where cucurbit crops were grown was carried out to assess the incidence and severity of virus symptoms and viruses associated with the crops and weeds in selected locations in Ogun and Osun, in southwest Nigeria, in June, 2012. In all, 38 leaf samples were collected in Ogun state and 52 in Osun state from cucurbit crops and weeds. Leaf samples were tested against  Cucumber mosaic virus (CMV), Melon necrotic spot virus (MNSV), Papaya ringspot virus (PRSV), Watermelon mosaic virus (WMV),Zucchini yellow mosaic virus (ZYMV) and Cucumber green mottle mosaic virus (CGMMV) using Double Antibody Sandwich (DAS) enzyme-linked immunosorbent assay (ELISA). All the fields surveyed had virus symptom incidences of 100% except for melon fields in Osun state with incidences of between 10 and 30%. In Ogun state, the occurrence of CMV was 5/31 (16.1%) while MNSV was detected in Lagenaria siceraria and T. occidentalis and it occurred in 6.5% of the leaf samples. In Osun state, CMV was detected in watermelon, melon and weeds found in all locations surveyed. The occurrence of CMV was 9/38 (23.7%) in the cucurbit crops and in 78.6% (11/14) of the weeds. PRSV and WMV also occurred in mixed infection with CMV in 7.1% respectively. CMV was the most widespread and prevalent virus infecting cucurbit crops and weeds.Cucurbits are economic crops in Nigeria which serve as additional nutritional supplements and also good sources of income for farmers. Viral diseases are a worldwide problem of cucurbits and a major limiting factor for cucurbit production. A survey of farmer’s fields where cucurbit crops were grown was carried out to assess the incidence and severity of virus symptoms and viruses associated with the crops and weeds in selected locations in Ogun and Osun, in southwest Nigeria, in June, 2012. In all, 38 leaf samples were collected in Ogun state and 52 in Osun state from cucurbit crops and weeds. Leaf samples were tested against  Cucumber mosaic virus (CMV), Melon necrotic spot virus (MNSV), Papaya ringspot virus (PRSV), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV) and Cucumber green mottle mosaic virus (CGMMV) using Double Antibody Sandwich (DAS) enzyme-linked immunosorbent assay (ELISA). All the fields surveyed had virus symptom incidences of 100% except for melon fields in Osun state with incidences of between 10 and 30%. In Ogun state, the occurrence of CMV was 5/31 (16.1%) while MNSV was detected in Lagenaria siceraria and T. occidentalis and it occurred in 6.5% of the leaf samples. In Osun state, CMV was detected in watermelon, melon and weeds found in all locations surveyed. The occurrence of CMV was 9/38 (23.7%) in the cucurbit crops and in 78.6% (11/14) of the weeds. PRSV and WMV also occurred in mixed infection with CMV in 7.1% respectively. CMV was the most widespread and prevalent virus infecting cucurbit crops and weeds.

The consumption of cassava crop per capita calories in many Africa countries ranked it as the second most important staple food crop. Despite its diverse utilities, the yield potential of cassava is greatly hampered by viral diseases and these differ from country to country, depending on the type of viruses present. Unfortunately, the recent sudden re-emergence of cassava brown streak disease (CBSD) in East and Central Africa is currently gaining more aggressive international attention in Africa and other concerned countries, due to the significant economic yield losses imparting to most poor resource farmers fields. However, selfless efforts from scientific researches to manage CBSD, including recommendations, still seems not to be complimented as expected with pro-active measures from relevant stakeholders, nevertheless the concerned farmers. Overall, the present review revisited a brief glance of the historical development of CBSD, progresses made so far with respect to management strategies. Even more, the paper suggests opinions which could be explore by the ones interested to help within research findings, as well as to bring the awareness and to prevent further spread in countries and/or regions where there is currently the outbreak of CBSD and which had not been yet affected.