Training on mass production of entomopathogenic nematodes for biological control of invasive insect pests

A team of global experts in the production of biocontrol agent provided a practical training on the mass culture of entomopathogenic nematodes at the Biocontrol Agent Facility of Rwanda Agriculture and Animal Resource Development Board (RAB), writes Dr Stefan Toepfer and Wayne Coles.

Dr Stefan Toepfer, Research Scientist Arthropod Biological Control and Integrated Crop Management Advisor based at CABI’s Swiss centre, joined Dr Xun Yan, from Zhongkai University of  Agriculture and Engineering  in Guangzhou, China, and Dr Bancy Waithira Waweru and Didace Bazagwira from RAB to train 13 technicians, lecturers and post-graduates.

The week-long training course – which covered the entire production cycles of the nematode-biocontrol agents to target pests such as the fall armyworm (Spodoptera frugiperda) – included 9 women from various stakeholder organizations.

Participants at the training session learn how to apply beneficial nematode-based biocontrol agents to fight crop pests (Photo: S. Toepfer).

Helping to make biological pest control agents locally available

This training was organised by RAB, who invited the global experts under a National Council for Science and Technology project NCST-NRIF-IDRC/SSR-AGR/002/2021 led by Ms Kajuga Nsamira Joelle. Such trainings are also part of the Plantwise Plus programme which aims to help make biological pest control agents locally available.

Participants learnt about starting the rearing process from isolation, subculturing, and mass culturing the symbiotic bacteria of the nematodes. They were also taught about the multiplication of the nematodes, harvesting, storage and different application techniques into the soil and above-ground, particularly against the fall armyworm.

Entomopathogenic nematodes are small soil inhabiting worms that multiply inside insects and have been used for the biological control of crop pests – which can cause devastating losses for smallholder farmers – for around 100 years.

The first description of the entomopathogenic vine weevil killing nematode Steinernema kraussei, for example, was made by Gotthold Steiner in 1923 – a landmark that will be celebrated at the meeting of the European Society of Nematologists in Logrono, Spain, in April 2024.

Alongside their use against soil insect pests – such as grubs or rootworms, they can also be used above ground against pests – like the fall armyworm  – if correctly formulated.

Entirely safe to farmers and consumers, livestock, crops, and the environment

As natural enemies of pests, those beneficial nematodes are entirely safe to farmers and consumers, livestock, crops, and largely to the environment. They are the third most traded group of biocontrol agents after Bacillus thuringiensis and Trichogramma parasitoids.

The quality control and formulation of beneficial nematode–based biocontrol agents are taught by Stefan Toepfer from CABI and Xun Yan from ZHKU during the training on nematode mass production (Photo: Xun Yan).

Entomopathogenic nematodes can be mass produced in several ways. However, the mass production of nematodes and their symbiotic bacteria is mostly based on using artificial media on sponges from which they can be easily harvested and used.

Dr Vincent de Paul from the University of Rwanda said, ″We are very grateful to have learnt about entomopathogenic nematodes and their mass production. Most of the things were very new to me.

″Many of us in Rwanda have limited experience with this type of biocontrol agents. This has now changed, which will open numerous possibilities in research and development for better food production in our country.″

Training built on previous technology transfers

The training built on previous technology transfers. For example, 29 biocontrol facilities were established under a EuropeAid in Democratic People’s Republic of Korea. This was achieved by CABI together with the biocontrol companies Andermatt Biocontrol Suisse and Lvbenyuan Biotec Ltd from the Institute of Zoology of the Guangdong Academy of Sciences (GIZ-GAS).

A similar facility had also been established by CABI and GIZ-GAS at RAB in Rwanda in 2014. This was financed by the AgriTT Research Challenge Fund of the then UK Department for International Development (DFID).

Participants at the training on the mass production of beneficial nematodes as biocontrol agents that took place at the Rwanda Agriculture and Animal Resources Development Board with the master trainers Stefan Toepfer from CABI, Xun Yan from ZHKU and Bancy Waithira Waweru from RAB (Photo: Anatole).

Other relevant stories

A story (in Chinese) about the training, from the perspective of Yan Xun, can be read here.