Browsing by Author "Van Damme P."

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Ethnobotanical survey of pesticidal plants used in South Uganda: Case study of Masaka district
(Academic Journals, 2010) Mwine J.; Van Damme P.; Kamoga G.; Kudamba; Nasuuna M.; Jumba F.
Use of synthetic pesticides in developing countries is not only limited by their being expensive but also the small (uneconomic) fields whose limited production costs cannot offset costs of agricultural implements like agro-chemicals. Subsistence farmers, therefore, have no choice but to use local methods of controlling pests, one of which is the use of traditional and of late introduced pesticidal plants’ extracts. In this study, whose main objective was to record all pesticidal plants used in Southern Uganda, Masaka district, it was established that thirty four species belonging to eighteen families are currently used in traditional plant production. Most useful species were Azadirachta indica and Tagetes minuta while the most frequently cited families were Meliaceae and Euphorbiaceae. It was noted that of the plant species recorded, some plants like A. indica, Melia azedarach, and T. minuta are already scientifically established pesticidal plants whereas others like Euphorbia tirucalli, Bidens pilosa, Vernonia amygdalina may be known for other uses but not for this purpose and hence the need for their efficacy evaluation. Some important pesticidal plants like Abrus precatorius, Euphorbia candelabrum and Phoenix reclinata were reportedly becoming increasingly rare and would need conservation. The need to carry out such surveys in order to obtain inventories was observed and recording this knowledge before it disappears with the aging farmers was seen as urgent.
Molecular Characterization of Tomato Leaf Curl Disease-Causing Viruses in Uganda
(African Journals Online, 2009) Ssekyewa Charles; Van Damme P.; Steele K. A.
In this study, Tomato Leaf Curl Disease symptom-bearing samples were collected from dry savannah (Eastern and Northern) and wet equatorial/tall grass savannah (Central and Western) agro-climati c zones of Uganda. Their total DNA was extracted using a modifi ed Dellaporta protocol. Virus DNA was amplifi ed with fi ve diff erent primer pairs for Tomato yellow leaf curl virus (TYLCV), Tomato yellow leaf curl Sardinia virus (TYLCSV-Sic) and Tomato leaf curl Uganda virus (TLCUV) as well as their combinati ons. The results indicated that there is wide variati on in the tomato leaf curl viruses in the Country. The viruses were grouped into 24 categories and three (3) disti nct virus genomes, namely, Tomato leaf curl Uganda virus-Soroti , Tomato leaf curl Uganda virus- Iganga (Pallisa) and Tomato leaf curl Arusha virus-Mubende, were characterized. Parti al results indicated occurrence of viruses related to TYLCV and TYLCSV-Sic in wet agro-climati c zones. Genomic variati on was detected within isolates and recombinati on was suspected.
Relationship between Tomato Yellow Leaf Curl Viruses and the Whitefly Vector
(African Journals Online, 2010) Ssekyewa C.; Van Damme P.; Nagawa F.; Kyamanywa Samuel; Steele K. A.
Tomato yellow leaf curl is prevalent in tomato growing districts of Uganda. The disease is known to be spread by a whitefly (Bemisia tabaci) in a persistent manner. Some of its symptoms are leaf curl, marginal leaf yellowing, malformation of fruits, stunting and dieback (in case of primary infection at early seedling stage), so the disease is economically important. Therefore, this study delved into the relationship between the disease and the vector in selected agro-ecosystems in the Country. The influence of weather and seasonality on the incidence of the disease and the vector was also investigated through a series of field experiments across a period of two years. New methods for trapping the vector were developed and applied to estimate its populations on individual plants and in the overall field environment. The findings were that whereas incidence of the disease is low at seedling stage, the whitefly population is highest at this stage. It was also found that the vector population is favoured by drought, so rainy conditions reduced it tremendously.