Plant-parasitic nematodes in pome and stone fruit orchards : biology and management in Washington

A diversity of microscopic round worms called nematodes inhabit orchard soils. Many of the nematodes in orchard soils contribute to soil health functions. Fungal feeding and bacterial feeding, predatory and omnivorous nematodes provide a number of services including nitrogen mineralization and plant pathogen suppression. However, plant-parasitic nematodes feed on plants; damaging roots and creating wounds which may serve as infection points for plant pathogenic fungi, thereby directly transmitting certain pathogens, such as viruses, to the host plant. Plant-parasitic nematodes have a needle-like stylet in their mouthparts which they use to feed on plant cells. Nematodes can either be migratory or sedentary. Migratory nematodes move through roots as they feed, disrupting plant cells or feeding entirely on the outer surface. Sedentary nematodes manipulate normal cell development and create a feeding site. All of these lifestyles and behaviors interrupt the plant’s ability to transport water and nutrients. Nematode feeding can also directly kill plant cells, root hairs, and even whole roots. Here we will describe a few key plant-parasitic nematodes that can cause damage in the orchard