Official Midterm Practice

Koch’s postulate

1. constant association of suspected causal agent and disease

2. suspected causal agent isolated and grown in pure culture

3. suspected causal agent induces disease in healthy plants

4. re-isolation from disease-induced plants yields the same causal agent

zoospore

motile cells produced by oomycetes

spalting

when a piece of wood is being colonized by multiple different fungi, black borders/outlines appear marking the boundaries of each fungi colony

perithecium

necked ascomata (pear/flask shaped), asci released through ostiole, characteristics of fungi causing foliar diseases or stem/branch cankers

anthracnose

broad category of leaf and twig blight, necrotic spots and lesions on leaves, death of leaf, dieback of branches

S strategy

stress tolerant strategy: slow spore germination, growth and reproduction rates, enzymatic capacity to utilize or degrade complex antifungal chemicals

disease triangle

host, pathogen, environment

endophyte

microbe that lives within plant tissues without harming it

appresorium

hyphal modification, adhesive pad on hypha that attaches to surface of host plant and penetrates cell wall

sporodochium

conidiophores aggregated into cushion

stroma

compact fungal tissue in or on which fruiting bodies are produced, holds water and prevents fruiting bodies from drying out

Chestnut blight causal agent

Cryphonectra parasitica

powdery mildews causal agent

Uncinula adunca

Tar spot causal agent

Rhytisma

cytospora dieback of balsam fir causal agent

Valsa freisi

sooty mold on pine causal agent

Capnodium 

cedar leaf blight causal agent

Didymascella thujina

brown felt blight causal agent

Herpotrichia juniperi, Neopeckia coulteri

cytospora canker causal agent

Cytospora chrysosperma, Valsa sordida

Hypoxylon canker causal agent

Hypoxylon mammatum

coral spot disease causal agent

Nectra cinnabarina

beech bark disease causal agent

Nectria coccinea var. faginata

butternut canker causal agent

Sirococcus clavigignenti-juglandacearum

black canker causal agent

Ceratocystis fimbriata

Eutypella canker causal agent

Eutypella parasitica

Nectria canker causal agent

Nectria galligena

Atropellis canker causal agent

Atropellis piniphila 

Scleroderris Canker causal agent

Ascocalyx abietina

Cytospora canker of spruce

Leucostoma kunzei

Lachnellula canker of larch causal agent

Lachnellula willkommei

black canker of spruce causal agent

Retinocyclus abietis