sanitation: removal and burning of infected plant parts: decontamination of tools: equipment: hands: etc.

saprophyte: organism that uses dead organic materials for food

scab: roughened, crustlike diseased area on the surface of a plant organ

sclerotium: compact mass of hyphae with our without host tissue, usually with a darkened rind, and cabable of surviving under favorable environmental conditions.

scorch: "burning" of leaf margins as a result of infection or unfavorable environmental conditions

secondary infection: infection caused by inoculum produced as a result of primary or subsequent infection

secondary inoculum: inoculum produced by infections that took place during the same growing seaso

septate: having cross walls

serology: method using the specificity of the antigen-antibody reaction for the detection and indentification of antigenic substances and the organsisms that carry them

shot-hole: a symptom in which small diseased fragments of leaves fall off and leave small holes in their place

sign: the pathogen or its parts or products seen on a host plant.

smut: disease caused by the smut fungi, characterized by masses of dark powedery and sometimes ordorous spores

soft rot: rot of a fleshy fruit, vegetable or ornamental in which the tissue becomes macerated by the enzymes of the pathogen

sooty mold: sooty coating on foliage and fruit formed by the dark hyphae of fungi that live in the honeydew secreted by insects such as aphids, mealybugs, scales, and whiteflies

sorus: compact mass of spores or fruiting structure foudn especially in the rust and smuts

spiroplasmas: pleomophic, wall-less microorganisms that are present in the pholoem of diseased plants

sporagiophore: specialized hypha bearing one or more sporangia

sporangiospore: nonmotile, asexual spore borne in a sporangium

sproangium: container or case of asexual spores

spore: reproductive unit of fungi consisting of one or more cells

sporidium: basidiospore of the smut fungi

sporodochium: fruiting structure consisting of a cluster of conidiophores woven togehter on a mass of hyphae

sporophore: hypha or fruiting structure bearing spores

sporulate: to produce spores

stem-pitting: symptom of some vial diseases characterized by depressions on the stem of the plant

sterilization: elimination of pathogens and other living organisms from soil, containers, etc. by means of heat or chemicals

strain: decendants of a single isolation in pure culture; an isolate

stroma: compact mycelial structure on or in which fructifictions are usually formed

stylet: long, slender, hollow feeding structure of nematodes and some insects

stylet-borne: virus borne on the stylet of its vector; a noncirculative virus

substrate: material or substance on which a microorganism feeds and develops, also a substance acted upon by an enzyme

suppressive soils: soils in which certain diseases are suppressed because of the presence in the soil of microorganisms antagnostic to the pathogen

susceptible: lacking the inherent ablility to resist disease or attack by a given pathogen

symptom: external and internal reactions or alterations of a plant as a result of a disease

systemic: spreading internally throught the plant body

teleomorph: sexaul

teliospore: sexual, thick-walled resting spore of the rust and smut fungi

telium: fruiting structure in which rust teliospores are produced

tissue: group of cells of similar structure which performs a special function

tolerance: ability of a plant to sustain the effects of a disease without dying or suffering serious injury or crop loss

toxicity: capacity of a compund to produce injury

transgenic plants: plants into which genes form other plants or other organisms have been introduced through genetic engineering techniques and are expressed, that is, produce the expected compund or function

transmission: transfer or spread of a virus or other pathogen from one plant to another