Worry as deadly parasite invades farms

Kevine Okello, a resident of Kano Plains in Kisumu County, is a worried man after an infectious parasite invaded his yellow oleander trees, locally known as chamama.

Because of its beautiful flowers and slender leaves, the oleander tree (Thevetia peruviana) is used by many in the larger Nyanza region to fence homes.

Oleander is a perennial tree, drought-resistant and doesn't require much input to cultivate.

Following the outbreak of the infectious parasite, which continues to ravage the tree as well as horticultural crops across the region, the locals have no option but to watch helplessly as their trees wither.

To kill its host, the parasite attaches itself to the plant and sucks food and water, leaving it victim to wither and finally dry up. “At first, it (the parasite) started as a beautiful tendril plant and we loved it. But a few weeks later, we noticed that the hosts started drying up,” says Okello.

Okello says the deadly disease has wiped out oleander from his three-acre plot in two years. The Government is equally worried, saying the parasite is a threat to afforestation and horticultural crops. If not contained urgently, the Government says, the parasite could threaten the country’s forest cover and food security.

“In Siaya, it was reported on mango and avocado trees. We are still monitoring the parasite to come up with suitable strategies to contain it,” says David Langat, principal scientist at the Kenya Forestry Research Institute.

Experts argue that if the parasite is not contained soon, it could expand to other counties within the region. “Even though parasites are specific to certain plant types, they can attack another plant species,” says Langat.

The parasitic plant, which easily germinates and spreads through dispersion, is exotic having originated in Peru, South America as an ornamental plant.

“Since we don’t have chemicals which can kill the parasite, we are encouraging people to use biological means, including manual removal, followed by drying and burning,” says Langat.

Oleander trees bloom almost all-year-round, with their main flowering period being during the rainy season. Before the rainy season or after flowering, the tree can be cut to keep it in shape, or to activate a rich blooming that appears just at the end of the branches.

Despite limited scientific evidence to support its uses, the tree has been used to treat heart failure in China and Russia for decades.

Oleander, which grows in temperate climates throughout the world, is a fast-growing small tree that can grow up to six metres high.