What began as being used in the decorations for weddings or in wreaths for funerals, has turned into a nightmare for Mbarara residents.
The congress weed (Parthenium hysterophorus) is prevalent in Kamukuzi, Kakoba and Nyamitanga divisions of Mbarara Municipality. Athanasius Gumisiriza, acting production and marketing officer, Mbarara District, says the weed has also been reported in Nyakayojo and Kakiika Sub-counties in Rwampara and Kashaari districts, respectively.
It is said to come through the border posts of Busia, Tororo and Malaba to Iganga and Buikwe with trucks carrying food aid for displaced persons during the insurgence in Teso. It has since spread to other districts: Busia, Namuntumba, Bugiri, Tororo, Mbale, Jimja, Masaka, Kasese, Isingiro, Rubirizi, Kisoro, Kanungu, Ntungamo and Rukungiri.
Dr Jenipher Bisikwa, of Makerere University, explains that the weed spreads very fast and is carried by water, animals and air. One plant can produce 10,000-15,000 seeds, which disperse to cover large areas. It germinates and flowers within 30 days, grows to six feet tall and can suppress other plants.
Contact with this plant causes dermatitis and respiratory complications in humans, dermatitis in livestock, due to the presence of the toxin, parthenin.
In animals, it affects milk production and meat quality, causes miscarriages and sometimes deaths, in extreme circumstances. It also reduces pastures both for domestic and wild animals as it has been cited in Queen Elizabeth National Park (QENP).
Checking the spread
Dr Margret Driciru, the wildlife veterinary officer, QENP, says the weed was first noticed along the roads and has rapidly spread to more than 100 metres inside.
“If this is not reversed, it will force the animals to migrate thus affecting tourism activities in the area,” she says
Gumisiriza points out the efforts done to check the congress weed in Mbarara. “We have created awareness for local leaders, farmers and the public. We are encouraging farmers to uproot it and burn or bury it to avoid re-germination. However, Dr Driciru discourages the use of chemicals to avoid affecting other organisms.
Congress weed is native to tropical America and was introduced into Africa, Asia and Oceania in cereal and grass seed shipments from US during the 1950s.