Root-knot, dagger and lesion nematodes
Plant-parasitic nematodes are microscopic roundworms that live in soil and feed on plant roots. Aboveground symptoms are poor growth, low yields and an “off” color. The symptoms may resemble those of nutrient deficiencies or virus diseases. Belowground symptoms include poor root development, root browning, root swelling and stunting or death of feeder roots. In new vineyards, nematodes may cause poor establishment and weak growth of young vines. Nematodes seldom kill vines but contribute to a steady decline in vigor. Dagger nematodes can also transmit certain viruses. Nematodes spread with soil and plant roots. Once established in a vineyard, nematode infestations tend to be permanent.