Nematodes of the genus Meloidogyne (the root-knot nematodes) are among the most economically damaging plant-parasitic nematodes affecting horticultural and field crops worldwide. Meloidogyne spp. infest a wide range of plant species, including many major crop plants such as tomato (Solanum lycopersicum), pepper (Capsicum annuum), cotton (Gossypium spp.), coffee (Coffea spp.), maize (Zea mays), and rice (Oryza sativa).
There are several techniques for extracting plant-parasitic nematodes from soil samples, roots, or aerial parts of plants. To select the most appropriate method, it is important to contemplate the time available for processing the samples, the effectiveness of each procedure in relation to the purpose of the extraction, and the equipment a method requires. In addition, it is essential to consider some characteristics of the nematode genus or species to be extracted, such as:
a) the parasitic habit (whether a nematode is a sedentary or migratory endoparasite, an ecto-endoparasite, an ectoparasite, etc.),
b) the life cycle (what stages are found in soil or plant tissues), and
c) the size and displacement capacity.
For the extraction of root-knot nematode eggs, it is necessary to consider the entire root system as well as the number of roots to process. This protocol for egg extraction from root galls was developed for the facilities and materials available in UC Riverside’s Department of Nematology. However, it can be adapted to different situations in other laboratories.