Incidence, Distribution and Characteristics of Major Tomato Leaf Curl and Mosaic Virus Diseases in Uganda

In Uganda, about 3 million households consume tomato. However, tomato yields (10 ton/ ha) are low due to poor agronomic practices, lack of high yielding and disease resistant varieties, and pests (Varela, 1995; Hansen, 1990; Defrancq, 1989). Viral diseases are the third major cause of low tomato productivity in Uganda. Therefore, a survey was conducted; symptoms observed on tomato were categorized, and screened for both ribonucleic and deoxyribonucleic acid tomato viruses. Genetic identity for one main virus disease was investigated. Serological and molecular techniques, i.e. DAS-ELISA (Clerk and Adams, 1977), TAS-ELISA (Macintosh et al., 1992), DNA hybridization (Czosnek et al., 1988), and PCR (Navot et al., 1992; Maniatis et al. 1982) were used. TYLCV-UG and ToLCV-UG homology with other begomoviruses, and their vector (Bemisia tabaci) relationship were studied. Major symptoms observed on tomato included leaf curl, mosaic and mottling, in descending order of importance. Ribonucleic acid viruses, i.e. Tomato mosaic virus (ToMV), Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV), Pepper veinal mottle virus (PVMV), Potato virus Y (PVY), Potato virus X (PVX), Tomato spotted wilt virus (TSWV) and Chili veinal mottle virus (ChiVMV), as well as deoxyribonucleic acid viruses, i.e. Tomato yellow leaf curl virus (TYLCV-UG) and Tomato leaf curl virus (ToLCV-UG) were identified. TYLCV-UG was found to be homologous with TYLCV-EG. ToLCV-UG replication gene and coat protein were different from the same genes of other ToLCVs. Virus incidence varied in space and time, and with management practices, crop development stage, and weather conditions. Number of plants infected with tomato yellow leaf curl viruses (TYLCVs) was inversely proportional to percentage marketable tomato yield (R = -0.14, p = 0.04). B. tabaci population, varied with micro-climatic conditions in the agro-ecosystem, and influenced TYLCVs incidence. Furthermore, an integrated package of uprooting infected plants and application of dimethoate insecticide was the most effective treatment in reducing whitefly populations and controlling TYLCVs. These results present a good starting point for tomato virus diseases diagnosis and management in Uganda. Future research is recommended.

Author dc:creator

• Ssekyewa, C

Contributors dc:contributor

• Van Damme, P
• Höfte, M

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

und

Identifier

https://biblio.ugent.be/publication/469971
http://doi.org/1854/6049
https://biblio.ugent.be/publication/469971/file/1878898

OAI identifier oai:identifier

oai:archive.ugent.be:469971