What are the most prevalent potato diseases in Rwanda?
Monday, November 15, 2021
The majority of farmers reported Potato Bacterial Wilt disease to be the major disease constraint to potato farming. / Net photo.

Scientists have said that there is a need for effective ways to cope with a deadly disease dubbed "Potato Bacterial Wilt (PBW) Disease” that continues to affect Irish Potato farmers.

According to the researcher, Florence Uwamahoro, the disease is widespread.

"We did a survey in 10 districts and we found that almost all farmers in the districts face the issue,” she said.

She said that there are risk factors including lack of knowledge in terms of agricultural practices.

"When potato plants are close together, there is a high risk of developing such disease,” she said.

She said that Monocropping, an agricultural practice of growing a single crop year after year on the same land, is also among the risk factors.

"Crop intercropping slows the disease spread,” she said, adding that no agro-chemicals can cure the disease.

"Farmers can even lose total harvest and the disease can also spread through affected potato seeds and soil,” The scientist explained.

Scientists say the Potato bacterial wilt (PBW) disease is considered as the second most important disease in potato production in Rwanda after late blight disease although a recent study reported that, according to the farmers, the damage caused by Potato bacterial wilt (PBW), is more severe than those caused by late blight disease.

They say control strategies for PBW disease include the use of healthy seed and planting in uninfected soil, use of less susceptible varieties, rotation with non-host plants, cultural practices such as nematode control, sanitation and chemical control adding an integrated strategy for these methods is recommended for reducing the incidence of bacterial wilt.

The majority of farmers (80 to 100 per cent) reported PBW disease to be the major disease constraint to potato farming followed by late blight reported by 0 to 73 per cent of the respondents in the different districts according to the research paper.

Six factors  such as, cropping system, grown variety, source of seeds, crop density and sharing of farm tools were tested and found to vary in association with PBW incidence and severity.

"Agricultural development efforts to limit the impact of PBW should focus on improving farmer adoption of best practices namely increasing spacing or decreasing planting density, practicing crop rotation, including other non-host crops in potato fields and sterilizing tools,” scientists recommend.

Biotechnology in fighting diseases

On part of Potato late blight disease, an imported new variety of Irish potatoes, produced through biotechnology, that will not require using agro-chemicals, as it is resistant to Potato late blight disease, could soon be tried in Rwanda, Patrick Karangwa, The Director General of Rwanda Agriculture and Animal Resources Development Board (RAB) said.

Karangwa said that biotechnology is set to help Rwanda to produce improved crops that are tolerant to drought, diseases and pests.

"The new variety produced through biotechnology to build its resistance to disease will not require using many agro-chemicals as farmers have been doing. This is a solution because the agro-chemicals and pesticides are harmful to the environment,” he said.

He said that the variety will also reduce the cost spent on agro-chemicals.

Rwanda produces an average of 916,000 tonnes of Irish potatoes every year, making it the third most popular food crop produced in the country.

Potatoes cover 3.9 per cent of the national total cultivated area.

The average productivity of potatoes is ten tonnes per hectare which is low as compared to yield potential.

The Northern volcanic region accounts for more than 80 percent of national potato production and 60 percent of the production are used directly for home consumption in this region.

According to Geraldine Mukeshimana, the Minister for Agriculture and Animal Resources, Open Forum on Agricultural Biotechnology (OFAB)  recently in Rwanda will be sharing experiences and practices in the field of biotechnology in the countries of Kenya, Uganda, Tanzania, Ethiopia, Ghana, Burkina Faso, Rwanda and Nigeria.

 OFAB is a partnership platform in Africa that contributes to creation of an enabling environment for biotechnology research, development, and deployment for the benefit of smallholder farmers in Africa.

"It is a big milestone in advancing agricultural research, application and an opportunity for our people to interact and get the latest information about agricultural biotechnology,” she said.

By embracing technological upgrading and building capacity for Rwandan farmers and rural value chain actors, she said they will make informed decisions to be at the same level with the rest of African countries who are already benefiting from agricultural biotechnology such as South Africa, Kenya, Nigeria, among others.

Mukeshimana said that the government of Rwanda recognizes the role of agricultural biotechnology to address the challenges facing the agricultural sector particularly, "those related to the adverse impacts of climate change such rising incidence of pests and diseases and loss of biodiversity.”

The embrace of Agricultural biotechnology in Rwanda will help to spur sustainable agricultural development in the face of dwindling factors of production such as limited land, she said adding , "It is time for Africa nations to redeem time, by increasing investment in science, technology and innovation.”

She said that there is a need to use home grown scientists’ innovations to help reduce the food import bill in Africa.

The food import bill for Africa rose to $49 billion in 2019 from $35 billion in 2015.

Law on GMOs pending

Juliet Kabera, the Director General of Rwanda Environment Management Authority said that the institution is closely working with Rwanda Agriculture and Animal Resources Development Board (RAB) to ensure that any biotechnology that is used is safe.

"We are the authority to handle biotechnology after Rwanda ratified Cartagena protocol to ensure bio-safety,” she said.

The Cartagena Protocol on Biosafety to the Convention on Biological Diversity is an international agreement which aims to ensure the safe handling, transport and use of living modified organisms (LMOs) resulting from modern biotechnology that may have adverse effects on biological diversity, taking also into account risks to human health.

It was adopted on 29 January 2000 and entered into force on 11 September 2003.

She said that Rwanda has designed a bio-safety strategy to ensure Rwandans are conscious.

"In the strategy we now have a draft of law on biosafety which is going to be discussed in the cabinet and later on in the parliament. We are establishing laboratories and raising awareness to be able to know what we are doing on the market especially when it comes to Genetically Modified Organisms (GMOs),” she said.