There are concerns over the potential spread of the invasive apple snail within Kenya’a irrigation schemes.
A study conducted by scientists from the Centre for Agriculture and Bioscience International and Kenya Plant Health Inspectorate Services said that drainage and irrigation canals might facilitate the pest’s movement into new areas.
The apple snail, regarded as one of the world’s worst invasive species, is originally from South America.
It was first reported in 2020 within the Mwea Irrigation Scheme, a key rice-growing area, where its presence has since caused significant concern.
According to the findings, 80 percent of the Mwea Irrigation Scheme is now infested by the pest.
The study, titled “Current and Potential Distribution of the Invasive Apple Snail (Pomacea canaliculata) in Eastern Africa: Evidence from Delimiting Surveys and Modelling Studies,” indicates that the invasive snail’s boundary has already expanded far beyond its initial point of infestation.
The research says the invasive snail is rapidly spreading throughout areas it has infested, becoming a major threat in the ecosystems.
Surveys were conducted across several key rice-producing areas, including Mwea, Bura, Hola, Ahero and West Kano, in order to map the snail’s spread and assess its potential risk to the surrounding regions.
The goal was to develop effective management strategies to contain the pest and limit its impact on the agricultural economy.
“More than 80 per cent of the Mwea scheme was infested with invasive apple snail, an expansion from the initial infestation point,” the study says.
The researchers said that areas such as Malawi, Madagascar and Uganda are particularly at risk due to the environmental conditions that favour the growth and spread of the snail.
Mozambique, Tanzania and Ethiopia also have localised regions where the species could thrive.
On the other hand, the study found that countries like Sudan, South Sudan, Eritrea, Djibouti, and Somalia present largely unsuitable conditions for the apple snail.
Given the snail’s ability to spread rapidly, researchers called for the implementation of strict quarantine measures to prevent further expansion and to protect neighbouring regions in Eastern Africa from the threat of an invasion.
“The arrival of the invasive snail adds to the already long list of challenges facing rice production in Kenya,” the researchers said.
“Identifying the current and potential spread of this pest is crucial for providing early warnings to decision-makers,” they added.
“This proactive approach will help mitigate the impact of potential invasions, allowing for the development of contingency plans to deal with any future spread of the pest effectively.”
The survey findings revealed that the spread of the snail has been significant, with 80 per cent of the Mwea scheme now affected.
However, there were no signs of adult snails or egg masses in other irrigation schemes, suggesting that, for now, the infestation has been largely contained to Mwea.
According to the Ministry of Agriculture, rice ranks as the third most important food crop in the country.
It plays an essential role in both household food security and farmers’ incomes.
About 80 per cent of Kenya’s rice production comes from irrigation systems, with the remaining 20 per cent being rain-fed.
The completion of the Thiba Dam in 2022 in Mwea is expected to increase the area and volume of irrigated rice, further highlighting the significance of controlling any threats to this vital crop.
The study says the invasive snail exacerbates existing challenges faced by the rice sector, making it even more difficult for farmers to maintain healthy crops.
The researchers add that the
management of the invasive snail
has mainly relied on physical and
cultural control methods.
