Publications by authors named "Rudolph R Shirima"
Cassava is an important food crop in western Kenya, yet its production is challenged by pests and diseases that require routine monitoring to guide development and deployment of control strategies. Field surveys were conducted in 2022 and 2023 to determine the prevalence, incidence and severity of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), whitefly numbers and incidence of cassava green mite (CGM) in six counties of western Kenya. Details of the encountered cassava varieties were carefully recorded to determine the adoption of improved varieties.
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- * Molecular techniques confirmed the presence of various virus species, including cassava brown streak ipomoviruses and cassava mosaic begomoviruses, with East African cassava mosaic virus also detected.
- * The study identified four whitefly species, significant pests for cassava, and categorized the local cassava into two mitotypes, providing essential data for future management strategies against these viral diseases and their vectors.
The present study characterizes and from cassava in eastern Democratic Republic of Congo (DRC). The Mitochondrial sequencing revealed the occurrence of six cassava mitotypes, which were designated into four haplogroups (SSA-ECA, SSA-CA, SSA2, and SSA-ESA) using KASP SNP genotyping. SSA-ECA (72%) was the most prevalent and occurred in the northern part of the surveyed area, in the Ituri and Nord/Sud-Kivu provinces, whilst SSA-CA (21%) was present in the south, primarily in Haut-Katanga.
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- Cassava brown steak disease (CBSD) is a major threat to cassava production in East and Central Africa, caused by two viruses, CBSV and UCBSV.
- A multi-country study aimed to identify and promote cassava cultivars resistant to CBSD across various conditions in Tanzania, where 17 different cultivars were tested.
- Results showed significant differences in CBSD infection rates based on location, with certain resistant cultivars demonstrating less than 20% incidence, while the CBSD was found to be more virulent than UCBSV.
Article Synopsis
- Cassava brown streak disease (CBSD) is a major threat to cassava production in East and Central Africa, primarily due to the lack of resistant crop varieties, leading farmers to recycle planting materials, which increases disease risk.
- A study conducted in Tanzania from 2013 to 2017 assessed the degeneration of various cassava varieties under high CBSD conditions, revealing that newly planted materials had lower disease incidence compared to recycled ones, especially during the long rains season.
- The research found that overall root yields were significantly higher during the long rains (Masika) compared to the short rains (Vuli), and recycling planting materials resulted in more unusable roots due to CBSD, particularly in the Vuli season.
The whitefy Bemisia tabaci, a species complex consisting of many morphologically indistinguishable species divided into distinct clades, is one of the most globally important agricultural pests and plant virus vectors. Cassava-colonizing B. tabaci transmits viruses that cause cassava mosaic disease (CMD) and cassava brown streak disease (CBSD).
View Article and Find Full Text PDFCassava brown streak disease (CBSD) is the most important virus disease of cassava and a major food security threat in Africa. Yearly economic losses of up to $100 million USD have been attributed to CBSD. The lack of information on plant-virus interactions has restricted progress in breeding for CBSD resistance.
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