Root knot nematode (Meloidogyne spp) is a plant parasitic nematode which lives in the soil, mostly in regions with hot climates. The parasite causes significant crop losses.
HOST RANGE
This parasite has a wide range of hosts and cause infections in many annual and perennial plants.
These include the following;
- Vegetables e.g. tomato
- Fruit crops e.g. bananas
- Ornamentals e.g. roses
- Legumes e.g. cowpea
LIFE CYCLE
- The root knot nematode goes through an embryonic stage of development which is comprised of four juvenile stages (J1-J4) and an adult stage.
- The female lays eggs into a gelatinous matrix which hatch into the second stage of juveniles which invade the plant roots. These juveniles undergo morphological changes and later molt into the next stage, eventually becoming adults.
- Female root knot nematode can live for about three months and produces hundreds of eggs.
- The life cycle of this parasite is depended on temperature.
IDENTIFICATION
The females and males of the root knot nematodes have distinct features. These include the following;
- Females– their bodies are translucent, elongated and oval to pear shaped. The tail termini are sometimes distinct, with or without striations.
- Males– bodies are vermiform, tapering anteriorly and blunt rounded posteriorly the blade tips are slightly curved ventrally with two distal pores.
However, these features cannot be seen with naked eyes.
FEEDING & DAMAGE
The infectious stage of root knot nematode is the second stage juvenile (J2) which occur freely in the soil. As they grow, they attach themselves to the host’s roots and begin feeding on the plant cells while getting deeper into the root cells. As these juveniles feed, they cause the roots to develop swellings/galls. These galls drain the plant’s nutrients.
Some of the above ground symptoms are stunting, wilting, chlorosis, etc.
Damage results in poor growth, decline in quantity and quality as well as reducing plant’s resistance to other pathogens and unfavourable ecological conditions.
SURVIVAL
These nematodes have the ability to overwinter, especially as eggs in the soil. They also can undergo temporary quiescence when the environmental conditions are not favourable
Their wide host range is also an advantage to their survival techniques.
MANAGEMENT
Considering the heavy losses attributed to root knot nematodes, it is important to prevent and eradicate them.
Although there are various methods which can be used to control these parasites, the use of chemicals (nematicides) has proved to effectively work out.
These nematicides are;
- ALONZE 50EC – this should be drenched to the soil at a rate of 6ml/20l
- ADVENTURE 0.5 GR – this can be applied in two ways;
- Mixed with basal fertilizers at the rate of 2kg ADVENTURE in 50kg fertilizer (DAP, CAN, NPK, etc.)
- Applied to the planting holes at the rate of 5g/hole
Other methods include;
- Field sanitation
- Soil solarization
- Crop rotation
- Planting resistant varieties
- Weed control
