Adventitious Roots: Roots that originate from an atypical location such as the stem or leaves. Cankers: Localized necrotic tissue on the stem, calyx, or penducles of the plant. Chlorosis: The fading, yellowing or whitening of green tissue due to a decrease in the amount of chlorophyll. Coalesce: To grow together into one spot. Cooper Fungicides: Compounds containing copper that are used to kill fungi and bacteria. Defoliation: Dropping of leaves from the plant. Disinfect: To kill or prevent the growth of microorganisms (usually disease causing) usually by chemical means. Distortion: Alteration or changing of the original shape or characteristic of the leaf or leaflets. Emergence: The point when the seedling shoot first becomes visible through the surface of the soil. Firing: Browning of the outer edges of the leaflets with a thin yellow band; also referred to as marginal necrosis. Hydathodes: Leaf openings at the terminus of a vein. Leaflets: One of the separate divisions of a compound leaf. A compound leaf is made up of several leaflets. Natural Openings: Openings on the plant that provide a point of entry into the plant by microorganisms. Necrosis: Death of cells or tissue resulting in browning or blackening of a localized area on the tissue. Nodes: Points on a stem where the leaves or buds originate. On-Site Diagnostic Assay: Rapid tests that cab be conducted in the field or the greenhouse. Pith: Spongy tissue that occupies the center of the stem. Plant Disease Diagnosis: The science of examining plants to identify their diseases. Puckering: A disease symptom in which the leaves or leaflets are cupped or pinched into bunches. Stippling: The appearance of tiny spots. Stomata: Openings on the leaf surface required for gas exchange. Streptomycin: An antibiotic produced by the soil bacterium Streptomyces griseus, used to kill bacterial plant pathogens. Stunting: A disease symptom in which there is a reduction in height due to a reduction in the length of internodes or a decreased in the number of internodes. Top Wilting: Wilting of shoots on the upper portion of the plant. Ubiquitous: Present all the time; widespread. Water-soaked: A disease symptom in which plant tissues or lesions appear wet, dark, and usually sunken and translucent.