Parasitic Nematode and their effect on plant
| September 16, 2020One of the biggest obstacles to sustainable agricultural production are plant parasitic nematodes living in the soil. The damages and heavy loss of crop yield in fruits and vegetables attributed to nematode infection is widespread all over the world.
Plant parasitic nematode are well present in most agricultural soil, However, because they are small, invisible and generally cause damage by attacking the roots of plant which is a below ground part, nematodes have been overlooks over the years as serious pathogen even more than the above-ground pathogens and pest, but yet they are a major constraint in food production worldwide.
Therefore, a proper awareness and understanding of how plant parasitic nematodes affect plants and their interrelation with other plant pathogens such as fungi, bacteria, and viruses are critical for identifying and
effectively managing infection to minimize the crop-damaging impact of nematodes and maximize crop yield.
How Nematode Affect plants
Root-feeding species of nematodes normally attach themselves to the plant root while some penetrate into the root cells. In both case, the mechanical injury caused by the nematodes is only a slight damage to the plant compared to the damage caused by the secretion of saliva and toxins which are injected into the plant while the nematodes are feeding.
The feeding process of nematodes accompanied with the release of toxins into the plant cells around the infected parts cause the affected plant to react leading to:
Death or devitalization of root tips which stops root growth and development
Swellings and gall formation which decreases the ability of plants to take up water and nutrition from the soil [this causes wilting of plant and increase the severity of nutrient deficiency]
Interrelation between parasitic nematodes and other plant pathogen
Nematodes by themselves are very potent in causing yield-damaging diseases to plants, however they can also be surrounded by fungi and bacteria, and are carriers of virus many of which have the potential to cause plant diseases. The mechanical injury caused by plant parasitic nematodes during feeding can be an infection court that opens channels of entry for other pathogens, especially fungi and bacteria.
The combined pathogenic potential of the relationship between plant parasitic nematodes and other pathogens [fungi, bacteria, virus] is far greater than the sum of the damages each of the pathogen could produce individually. Below are some ways in which nematodes combine with other pathogens:
Nematode – Fungus disease Complex: The incidence and severity of most fungus infection increase significantly when the plants are also infected by nematodes. This increases the severity of crop loss from even small amount of infection or nematode population.
Nematode – Bacteria disease Complex: Nematodes primarily acts as vectors for carrying bacterium from plant to plant and they also facilitate entry of bacterium into host plant by inflicting injury on the plants, this provides the bacteria with an infection court that assist infection.
Nematode – Virus disease Complex: Nematodes are vectors for transmitting viral infection, they transmit the viruses after feeding on infected plant and can remain infective for long period of time.