Source: University of California Cooperative Extension, UC Riverside Department of Nematology, Missouri Botanical Garden

Nematodes are very tiny, microscopic worms that mostly live in soils, although foliar nematodes live in leaves. While some species harm plant roots, others are beneficial by attacking and killing pests.

Still, these worms can cause tremendous economic damage in production horticulture. As their bodies are typically microscopic in size and transparent, they are difficult to detect and to identify. Most nematodes, like root-knot nematodes, occur in soil or in subterranean plant parts. They feed on living plant tissues, influence the plant's physiology and may cause below and above ground symptoms such as root galling, lesions, stunting, wilting or chlorosis. Most of these symptoms are non-specific and can be attributed to a number of abiotic and biotic problems.

Foliar nematodes, also named bud and leaf nematodes, occur mainly within the leaves and crowns of many herbaceous perennials.

Foliar nematodes have broad host ranges and are capable of infecting hundreds of species of plants, including woodies and perennials. The host range for A. fragariae could be greater than 250 species.