Typical root symptoms indicating nematode attack are root knots or galls, root lesions, excessive root branching, injured root tips and stunted root systems.
Symptoms on the above-ground plant parts indicating root infection are a slow decline of the entire plant, wilting even with ample soil moisture, foliage yellowing and fewer and smaller leaves.
These are, in fact, the symptoms that would appear in plants deprived of a properly functioning root system. Bulb and stem nematodes produce stem swellings and shortened internodes.
Bud and leaf nematodes distort and kill bud and leaf tissue. In some cases, such as with SCN, yield loss may take place with no visible symptoms.
Bio-Nematocide： Paecilomyces lilacinus