After giving a number of educational talks this winter, I have once again reminded myself that there is one potentially serious pest that goes largely unnoticed and under-diagnosed in the green industry as a whole – nematodes. Nematodes are microscopic worms that feed largely on roots but sometimes on foliage causing nutrient deficiencies, drought-like symptoms and more. Nematodes can be extremely difficult to do anything about after the fact, and like many pests, being pro-active is the best measure.