Climate Change partially responsible for cocoyam blight

People who love eating ‘achu’ will have to tame their appetite as restaurants in big cities in Cameroon which specialised in this delicacy have greatly been affected by the increase in the prices of cocoyam.

In cities like Yaounde and Douala, a bucket of cocoyam now costs FCFA 4,000. “What we use now to prepare achu is what should have been used as seeds. I am afraid we may not even have seeds for the next farming season and that means no achu,” Regina Shiri, a restaurant owner in Bamenda said.

The changes in climate, witnessed in Cameroon, according to scientists, have greatly favoured the prevalence of a fungus affecting cocoyam. According to a September 2013 journal article written by Mbong et al, the pathogen can cause rapid and complete defoliation and crop destruction. Under certain circumstances, the disease can attack harvested crops and cause heavy losses during storage.

The article holds that the epidemic was widespread in Cameroon during the 2010 rainy season, between April and November, in all the cocoyam-growing regions, namely the Southwest, Northwest and Littoral.

The aforementioned regions are still suffering because of the recurrence of the disease. However, there were previous reports of a cocoyam blight-like disease attributed to P. colocasiae in Nigeria, Ethiopia, Equatorial Guinea and this has occurred more recently in Cameroon.

Not much has been done on P. colocasiae in Cameroon and this seems to be the first observed record of the disease, which poses a serious threat to the production and biodiversity of this important food crop.

Research carried out by some Cameroonian scientists, Chief of the Phytosanitary Unit of the Ministry of Agriculture and Rural Development, Northwest Region, Michael Mboh, Dr. Zachée Ngoko, a plant pathologist; plant breeder, Dr. Njuallem and Nematodist, Jacob Atanga, reveals that climate change accounts partially for the prevalence of the fungus.

According to Mboh, in an article in the Farmer’s Voice, the fungus is transported by the winds during the dry season. It therefore may have been deposited on leaves of crops. During the rainy season, the spores find a favourable condition for their propagation. On whether the consumption of affected cocoyam could be harmful, Mboh said it is however safe to consume them.

“We have fungi attack on tomato, huckleberry and other crops, but people continue to eat them. We cannot point any sickness that stems from this disease. The first thing we say is, eat your colocasia if you are lucky to have the tubers, because, when the leaves are destroyed, the plant ends up yielding nothing,” Mboh said.

He prescribed the use of some chemicals such as Metrostar-500 WP, Phostonic 80 WP and Nordox Super, as temporary measures to curb the spread of the disease.

Proposing solutions to the spread of the fungi, Dr. Ngoko remarked that the tubers are rotting because they contain a lot of water.

“The first measure is to save the plants that are not infected for future seed production. For temporary measures, we suggest that some known molecules be taken to affected areas to reduce the effects of the spread of the disease.

People should not plant tubers on affected farms. They can rotate their crops by planting beans or maize and remove all the colocasia around to cut off the cycle of this disease.

In affected regions, we should quarantine and make sure that we do not move colocasia from there to disease-free areas. We should do everything at the national level to have seeds for the next farming season, while waiting for research to come out with tolerant varieties.”

Although, the fungus has not resurfaced in the last three seasons, cocoyam is absent in the market and in the menu of families who depend on it.