Nematodes are tiny microscopic worms comprising diverse trophic groups (eg. plant feeders, bacterial and fungal feeders, animal parasites) they are found worldwide in most habitats (such as soil, water, sea and in plants and animals). At icipe we work with nematodes in soil. Most nematodes in soil are beneficial and play an important role in nutrient cycling, others play a role in suppressing insect populations. A few species however are detrimental to plant health.
Intensive agriculture and complex small holder farming systems often leads to a build-up of pests that become difficult to manage. Among these pests are plant parasitic nematodes. They infect plant roots and cause direct yield loss by preventing adequate water and nutrient uptake by the plant, or indirect losses due to secondary fungal or bacterial infections through the wounds caused by root feeding nematodes.
The problem with plant parasitic nematodes is that they are essentially underground and out of sight and cause non-specific symptoms on plants, hence are generally neglected pests. Most farmers are unaware of nematodes and usually discover them when it is too late. In Sub-Saharan Africa (SSA), there is a lack of active nematologists (scientists specializing on nematodes), though the capacity and expertise is picking up and the outlook is positive. Working with nematodes requires expertise on diagnostics which can be challenging as the distribution of nematode species in SSA is not well known. Another challenge is the poorly known host range and cropping systems that affect nematode populations.
However, it is well known that root knot nematodes (Meloidogyne spp.) globally are probably the most economically damaging, especially in vegetable production, mainly due to their wide host range complicating crop rotation systems. Lesion nematodes (Pratylenchus species) are also wide spread in banana and vegetable crops, and their mode of feeding (puncturing roots) often leads to secondary infections of other pathogens. Cyst nematodes, such as the potato cyst nematodes (PCN) are quarantine pests (in more than 100 countries) due to their serious threat to potato production. There unique life cycle involving long-lived cysts that can survive for years without a host is a major constraint to successful management and preventing its spread.
Beneficial nematodes such as the entomopathogenic nematodes have a unique life cycle involving symbiotic bacteria that are pathogenic to host insects. These nematodes are successfully mass produced and available in many countries for biological control of target insect pests. In SSA there is a need to enhance research and use of these nematodes in biological control of susceptible insect pests.
For further information, contact:
Solveig Haukeland (email@example.com)
NIBIO (Norwegian Institute for Bioeconomy Research)