Protecting harvests from hidden threats: A decade of NemAfrica’s work for farmers

NemAfrica at 10: How science is helping farmers beat potato and root pests

NemAfrica, founded to unite experts in nematology research in Africa, is a joint nematology laboratory between IITA–CGIAR and the International Centre of Insect Physiology and Ecology (ICIPE). NemAfrica works to tackle nematode pests and microscopic worms that attack a wide range of key crops, such as potatoes. 

Dr Danny Coyne, Nematologist and co-lead of NemAfrica at IITA, shares reflections on the work of NemAfrica, which he co-leads alongside Solveig Haukeland at the International Centre of Insect Physiology and Ecology (ICIPE).

Why NemAfrica?

To combine forces from two institutes and create synergy and critical mass towards expanding nematology research and capacity in Africa.

Looking back over the past 10 years, what has been the most surprising discovery or unexpected challenge in nematology research?  

There are regular discoveries related to recording new hosts for certain species of nematodes, finding new species in new locations, and discovering new ways and technologies for managing nematode pests. But probably the most surprising discovery was the very high prevalence of potato cyst nematodes across Kenya, and their presence in other East African countries, posing a major threat to the potato industry across East Africa.

What was the biggest gap in nematology research, and how did you fill it when you launched NemAfrica?

The biggest gap was farmers’ and agricultural staff’s lack of awareness and knowledge, which remains probably the greatest challenge. How do we create better knowledge and understanding of nematode pests and how farmers manage them?

Are African governments and research institutions doing enough to integrate nematode science into national food security strategies?

Definitely not, largely due to the lack of awareness by researchers and agricultural staff.

You work with invisible pests. How did you end up chasing microscopic worms underground for a living?

Originally, I received a grant for my MSc and continued from there.

What efforts are being made to increase the number of nematologists in Africa?

Minimal in general – except through a limited number of initiatives and thereon through individual nematologists. This is why NemAfrica and its extensive network of partners are so important in this respect.

Why are farmers battling something they can’t see—and often don’t know exists?

They are not battling exactly, as they are mostly unaware of them. They are battling to overcome reduced yields and lower harvest weights, which nematode pests can cause, and battling losses due to damaged, deformed, or rotted tubers caused by them.

You have helped develop new nematode-resistant potato varieties. How do they work—and can they outsmart the current pests?

We have just introduced two new varieties resistant to PCN to Kenya, which were developed naturally by breeders in Scotland. The resistance is durable and works well, but it is always possible for resistance-breaking populations of nematodes to develop. Consequently, managing nematode pests is an ongoing battle, as it is against other pests and diseases.

What are the biggest barriers preventing smallholder farmers from adopting nematode-resistant crops or sustainable management practices?

An initial major barrier is that farmers are mostly unaware of nematodes and do not understand the reason for a nematode-resistant variety. However, a big barrier to adopting new pest and disease-resistant varieties is their possible unsuitability to consumers, who may not like the taste, texture, or color. Adopting and accepting new varieties relies on combining several preferred traits, including agronomic traits. Introducing new crops can take time for farmers (and consumers) to become familiarized with them and understand that they have value, which is ultimately financial. New management options require demonstrating their benefits to crop production and returns to farmers, and they are readily applicable or easy to use.

What limitations have been faced in tackling the challenge of nematodes in Africa?

A major challenge remains their hidden nature and lack of visibility and knowledge by farmers in the first instance. Thereafter, limited nematology expertise further drags progress in creating awareness of nematodes. So, it is a slow march to create more nematology expertise and improve nematology knowledge at large. It takes time. This includes the integration of nematology in undergraduate studies, as a standalone topic in agriculture and biology programs. Normally, nematology is tagged on to the back of pathology or entomology, and taught by non-nematologists, who may not be as interested or knowledgeable and thus may not have the same zest or energy for nematology.

How can agroecological approaches (e.g., crop rotation, intercropping) be optimized for nematode management in different African regions?

Several agroecological methods can help, but due to expansive host ranges for some of the most problematic nematodes, rotation is not always effective; in addition, there is often a mixture of nematode species present at the same time. So, while rotation with non-host crops may help suppress and manage one nematode pest, it may not be effective against the others present, taking the place of the controlled species. However, cover crops, antagonistic crops, and crop rotations can be effective, provided farmers are willing to use them, which they may not always be happy to do.

If you could solve one major nematode-related problem in the next 10 years, what would it be and why?

It is difficult to pin down one single problem. The PCN issue in East Africa is here to stay. They are very difficult to eradicate and essentially impossible. Therefore, it is a case of managing the problem to reduce the losses and population densities. We can provide the guidance and tools to do this by employing a combination of tactics or technologies. A cross-cutting nematode problem, however, is the root knot nematode problem. They can devastate many crops and are also very difficult to control. A few key species have very wide host ranges, reducing the impact of crop rotation. However, some resistance in some varieties of crops, though this generally does not work against all root knot nematode species.

Effectively, it requires a basket of options to overcome root knot (and nematode pests in general), but we need more resistant varieties to help with this. They are very damaging, but if we can reduce the impact of PCN in East Africa over the next 10 years, then this would be a key goal. But it would no doubt take more than 10 years.

What gives you hope that we can finally turn the tide underground?

The energy, enthusiasm, and genuine interest of our next generation of nematologists – our students, interns, and staff in working nematodes – gives us much hope that things are changing and will continue to change and turn the tide. The more expertise and knowledge generated through NemAfrica, our partners, and university collaborators, the greater the knock-on effect towards extending information and awareness of nematodes in agriculture.

What next for NemAfrica?

Keep on keeping on…

 

Contributed by Danny Coyne and Barbra Muzata