Negative impact of nematodes on food security in Africa

The often overlooked problem of plant parasitic nematodes is having an adverse impact on food security in Africa. This was according to Dr Nancy Ntidi, nematologist at the Agricultural Research Council’s (ARC) Grain Crops Institute in Potchefstroom.

She said the impact of the nematodes on leafy vegetables on the continent was of particular concern.

“These vegetables are an important source of micronutrients and bioactive compounds. Despite the adaption of the vegetables to hot and dry climatic conditions, such crops are prone to infection by various diseases and pests, incuding plant-parasitic nematodes.”

According to Ntidi, plant-parasitic nematodes were microscopic worms which caused significant plant damage that could result in the total destruction of plant material. These pests constituted some of the most abundant on Earth and were adapted to survive in any environment.

African leafy vegetables species in the Amaranthus, Bidens and Solanum genera were widely consumed in Africa and were important sources of food for the poor, both in urban and rural settings.

A recent study by a team from the ARC and North-West University indicated that none of the African leavy vegetables sampled and evaluated were immune to the root-knot nematodes.

Substantial variation nevertheless existed among genotypes. The nematode pests also affected staple food crops such as maize, legumes and vegetables. “The production of susceptible African leavy vegetables may therefore exacerbate the nematode problem in areas where smallholder farmers practise agriculture,” Ntidi added.

Farmer’s Weekly previously reported that plant parasitic nematodes were only identified as major pests in 1855, when pioneering mycologist and plant pathologist Miles Joseph Berkely discovered root-knot nematodes on cucumbers.

Four years later, botanist Hermann Schacht discovered cyst nematodes on sugar beet. Since then, nematodes have been shown to attack many crops throughout the world.

All plant parasitic eelworm species limit the uptake of water and nutrients in crops. – Annelie Coleman