Images and lecture material were not entirely created by J. Bond ** Images and lecture material were not entirely created by J. Bond. Some of this material was created by others.**

Rhizopus sp. on peach Rhizopus sp. on sunflower

Plant Pathology – G.N. Agrios

TRUE FUNGI ASCOMYCETES - called the sac fungi because sexual spores (ascospores) are produced in a sac (ascus). This is the largest group of fungi (35k +) with the most economically important members.

ASCOMYCETES Characteristics : 1. Most are facultative parasites - they can survive in soil or plant debris, often for several years. A few are obligate parasites. 2. They produce a cellular hyphae (i.e., with distinct cell cross walls). 3. They produce a stroma - a mass of hyphae in which fruiting bodies are produced. 4. Sexual spores = ascospores. They are produced in groups of 8, which are enclosed in a single ascus (asci). 5. Ascospores in asci are produced in an ascocarp. There are several basic types of ascocarps, but each fungus produces only one type:

Plant Pathology – G.N. Agrios

Ascocarps a. Naked - asci are produced exposed on a plant surface, i.e., not in an ascocarp. Ex: Taphrina deformans - peach leaf curl Ex: Saccharomyces spp. - the yeasts

Naked - asci

Ascocarps a. Naked - asci are produced exposed on a plant surface, i.e., not in an ascocarp. b. Cleistothecia - asci are produced in a completely closed spherical structure. Ex: Sphaerotheca pannosa - powdery mildew of rose Ex: Erysiphe graminis - powdery mildew of wheat Plant Pathology – G.N. Agrios

Cleistothecia APS Slide Collection APS Slide Collection

Ascocarps Ex: Claviceps purpurea - ergot of grains a. Naked - asci are produced exposed on a plant surface, i.e., not in an ascocarp. b. Cleistothecia - asci are produced in a completely closed spherical structure. c. Perithecia - asci are produced in a nearly-completely closed structure with a single opening and a distinct wall. Perithecia can be round or some version of flask-shaped. Ex: Claviceps purpurea - ergot of grains Ex: Ophiostoma ulmi - Dutch elm disease Ex: Cryphonectria parasitica - chestnut blight Plant Pathology – G.N. Agrios

Perithecia APS Slide Collection APS Slide Collection

Ascocarps a. Naked - asci are produced exposed on a plant surface, i.e., not in an ascocarp. b. Cleistothecia - asci are produced in a completely closed spherical structure. c. Perithecia - asci are produced in a nearly-completely closed structure with a single opening and a distinct wall. Perithecia can be round or some version of flask-shaped. d. Apothecia - asci are produced in an open cup- or saucer-shaped structure. Ex: Monilina fructicola – brown rot of stone fruits Ex: Sclerotinia sclerotiorum - white mold of bean Plant Pathology – G.N. Agrios

Apothecia APS Slide Collection APS Slide Collection

Ascocarps Naked - asci are produced exposed on a plant surface Cleistothecia - asci are produced in a completely closed spherical structure. Perithecia - asci are produced in a nearly-completely closed structure with a single opening. Perithecia can be round or some version of flask-shaped. Apothecia - asci are produced in an open cup- or saucer-shaped structure. Pseudothecia (aka ascostroma) - asci are produced in cavities without a distinct wall within a stroma of mycelium within host tissues. Ex: Venturia inaequalis - apple scab Ex: Guignardia bidwellii - black rot of grape Plant Pathology – G.N. Agrios

Pseudothecia APS Slide Collection APS Slide Collection

Ascocarps Naked - asci are produced exposed on a plant surface Cleistothecia - asci are produced in a completely closed spherical structure. Perithecia - asci are produced in a nearly-completely closed structure with a distinct wall with a single opening. Perithecia can be round or some version of flask-shaped. Apothecia - asci are produced in an open cup- or saucer-shaped structure. Pseudothecia (aka ascostroma) - asci are produced in cavities without a distinct wall within a stroma of mycelium produced within host tissues.

Teleomorph vs Anamorph The teleomorph (perfect stage) is the sexual stage The anamorph (imperfect stage) is the asexual stage APS Slide Collection APS Slide Collection Nectria - perithecia Fusarium - conidia