Soybean Diseases
Glossary
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- Apothecia (sing. apothecium)
- Saucer-shaped,
mushroom-like fungal structures that produce spores.
- Chlorotic
- The yellowing of a plant's normally green
leaf tissue, due to the absence of chlorophyll.
- Conservation tillage
- Any tillage or planting system
that leaves 30 percent or more of the soil surface
covered with crop residue after planting, to reduce
soil erosion by water.
- Cotyledons
- The first emerging pair of leaves of the
soybean seedling.
- Damping off
- Seedling collapse due to rot of seeds
before or after germination, generally due to fungal
infection.
- Epidermis
- The outer surface of a leaf, stem or root.
- Hypocotyl
- Component of a seedling soybean stem
located beneath the cotyledons.
- Longitudinal
- Running lengthwise.
- Microsclerotia (sing. microsclerotium)
- Tiny, dark
bodies (masses of hyphae with a thick rind) formed
by certain fungi as survival structures.
- Mosaic
- A pattern of light and dark areas in a leaf that
is frequently a symptom of a virus infection.
- Mottle
- Irregular light and dark-colored areas on
plant parts that are frequently caused by a virus.
- Necrotic
- Dead; chlorotic areas may become necrotic
as disease progresses.
- Oospore
- Thick-walled survival spore of some fungi.
- Partial resistance
- A term used to describe resistance
made up of more than one gene. Also known as
horizontal resistance or field resistance.
- Pathotype
- A classification system used for Phytophthora
sojae. Similar to race, but better suited to the
increasing pathogen diversity of Phytophthora sojae.
- Pycnidia (sing. pycnidium)
- Spore containers that
are the fruiting structures of some fungi, visible to the
naked eye as tiny dots or bumps on the plant surface.
- Race
- A distinct population within the same species
with relatively small morphological and genetic
differences. Races differ in their ability to colonize
potential host plants.
- Sclerotia (sing. sclerotium)
- Seed-like structures
formed by some fungi to survive winter or remain
dormant until conditions are favorable for growth
and/or plant infection.
- Senescence
- The natural decline and death of plant
tissues due to aging.
- Stomates
- Natural openings in leaves that allow the
exchange of air.
- Toxin
- When pertaining to plants, this is a chemical
compound that causes damage to plant cells. Sometimes
released by disease-causing organisms.
- Zoospores
- Spores that can swim in water.
