A group of fungi that may consist of one cell or have filaments (hyphae) with few or no cross walls and that reproduce sexually by union of two sex cells.
A disease produced by some unfavorable physical or environmental factors (e.g., light, temperature, water, soil nutrients, chemical, physical or mechanical injury).
Microorganisms found in phloem tissue that resemble mycoplasmas in all respects except that they cannot be grown on artificial nutrient media (yet). Formerly known as mycoplasmalike organism (MLO).
To remove and destroy undesired individual plants from a planting on the basis of disease infection, not being true-to-type, insect infestation, or other reason.
nematodes that tunnel partially into roots, their heads entering to establish permanent feeding sites while their bodies remain outside. The nematode does not move after this. (Examples: citrus nematode, Tylenchulus semipenetrans.)
nematode that tunnel into the roots, establishing permanent feeding sites from which they do not move. They may protrude from roots as they grow. (Examples: root-knot, Meloidogyne spp.; and cyst nematodes, Heterodera spp.)