Chapter 6-11 Flashcards
Conidia
are asexual spores produced on specialized hyphae known as a conidiophore
Sporodochium
a superficial, cushion-shaped asexual fruiting body consisting of a cluster of conidiophores
Synnema
compact or fused, generally upright conidiophores, with branches and spores forming a headlike structure
Acervulus
an erumpent, cushionlike fruiting body bearing conidiophores, conidia, and sometimes setae
Pycnidium
an asexual, globose or flask-shaped fruiting body containing conidia
Ascomycota Asexual Reproductive Structures
A. Sporodochium B. Synnema C. Acervulus D. Pycnidium
Ascomycota Sexual Reproductive Structures
Ascospores, Apothecium, Chasmothecium/Cleistothecium ,Perithecium, Pseudothecium
Ascospores
(4 to 8) within an ascus (sac fungi)
Apothecium
an open, cuplike or saucerlike, ascus-bearing fungal fruiting body (ascocarp), often supported on a stalk
Chasmothecium/Cleistothecium
a spherical ascocarp that is closed at maturity
Perithecium
a flask-shaped or subglobose, thin-walled fungus fruiting body (ascocarp) containing unitunicate asci and ascospores
Pseudothecium
a perithecium-like fruiting body containing bitunicate asci in unwalled locales or cavities
Peach leaf curl – Taphrina deformans
Symptoms – thickened curled red or yellow colored leaves in the spring, may blight shoots and cause lesions on fruit if severe
Peach leaf curl management
- Available resistant varieties include Frost, Indian Free, Muir, and Q-1-8
- One fungicide application between leaf fall and bud swell
- Conventional–Ziram–Chlorothalonil–Fixed copper •Organic–Bordeaux mixture–Some copper compounds
Apple scab – Venturia inequalis
Symptoms: Lesion mostly on leaves and fruit first appears as a lighter shade of green and is circular, lesions increase in size it becomes olive-colored and velvety due to production of asexual spores
Apple scab management
- Cultural –fall foliar application of urea–chopping fallen leaves does not improve control in Cal–remove neighboring crab apples
- Host resistance – available but not popular varieties
- Chemical protection – fungicide applications to prevent primary infections
Powdery mildew of lettuce – Erysiphe cichoracearum
Signs: White powdery growth on upper and lower leaves, and small brown/black spots (chasmothecia)
–Symptoms: In advanced stages leaves dry out and become brown
Powdery mildew of lettuce Management
•Begin fungicide treatments as soon as symptoms are observed –Sulfer –Azoxystrobin
Strawberry anthracnose – Colletotrichum acutatum
Symptoms: White to light brown water soaked spots on fruit – sunken, lesions on leaves and stems, crown tissue may decay and may have a mass of salmon colored spores, stunting and chlorosis may occur
Strawberry anthracnose management
- Soil fumigation and solarization
- Fungicide dips prior to planting
- Rotate to non-host crop – broccoli or mustards•Disease free plantings
- Proper irrigation – minimize overhead irrigation
- Remove infected plant parts
Brown rot – Monilinia fructicolaand M. laxa
–Symptoms – blossom blight and ripe fruit phases, mummies–
Signs – gray brown spore masses on blighted tissue, apothecia on mummies in spring
Brown rot management
- Cultural – reduce inoculum by removing mummies, pruning out twig cankers
- Host resistance – varies from susceptible to very susceptible
- Chemical protection – fungicide applications during bloom and again during ripening if conditions conducive
Watery soft rot/ cottony rot – Sclerotinia sclerotiorum and S. minor
–Symptoms – Soft rot, stem rot, damping-off, flower blight–
Signs – fluffy white mycelium and black irregular sclerotia on plant, soil line or stems and petioles, apothecia develop following cool and wet weather
Watery soft rot/ cottony rot management
- Exclusion - avoid introducing to new fields•Eradication - 2-3 year crop rotation in coastal areas (S. sclerotiorum ascospores airborne)
- Cultural Practices – Avoid overly wet fields, keep surface of beds dry, canopy management, tillage, remove weed hosts
- Biological – Several fungal species are parasitic •Chemical protection – vinclozolin (Ronilan), iprodione (Rovral) or dichloran (Botran)
Gray mold – Botrytis cinerea
–Symptoms = Light brown lesions, rot, mummification
–Signs = grey mold, black irregular sclerotia
Gray mold management
- Remove and destroy infested material
- Pick all ripe fruits
- Manage water
- Chemical – developed a forecasting model based on temperature and wetness data
Early blight of tomato and potato - Alternaria solani
–Symptoms: Leaf spots are leathery and often have a concentric ring pattern, spots on fruit are sunken, dry, and may also have a concentric pattern
Early blight of tomato and potato Management
- Disease-free seed or fungicide treated seed•Crop rotation
- Resistant varieties
- Adequate fertility to maintain vigorous crop
- Fungicide applications if weather conditions conducive to disease development
Vertcillium wilt - Verticillium dahliae
–Symptoms: Wilt and chlorosis, vascular discoloration in roots and stems
–Signs: microsclerotia
Fusarium wilt – Fusarium oxysporum
–Symptoms: Wilt and chlorosis, vascular discoloration in roots and stems
Wilt managements
- Long crop rotation of 4-6 years
- Remove infested debris
- Solarization
- Proper irrigation and fertilization
- Resistance
Dutch Elm disease
–One of the most destructive shade tree diseases in North America and environmental disasters in Europe
–Many of the elm trees in North America and Europe were planted in rows along streets and walkways
–Large, overarching branches created beautiful shady canopies
Chestnut blight
–Environmental disaster to Eastern US forests
–Introduced in early 1900s, by 1940 most mature American chestnuts were wiped out, still a significant problem
Ergot of Rye
–Causes ergotism
–Strange mental aberrations, hallucinations, a feeling of burning skin or insects crawling under the skin. Women frequently miscarried, and fertility was generally reduced during outbreaks
–These strange behaviors have been linked to ergotism during the French Revolution and witchcraft in Europe and the U.S.
–Ergot contains alkaloid mycotoxins•Vasoconstrictors and LSD
Botryosphaeria panicle and shoot blight of pistachios
–Discovered in Durham in the northern Sacramento Valley in 1984
–Yield losses from 40 to 100% were not uncommon
Basidiospore
Sexual spores of the basidiomycota
Basidium
Specialized cell in which karyogamy and meiosis occur that produces haploid basidiospores
Teliospore
thick walled spores that form basidia
Autoecious
rust can complete its entire life cycle on a single host species
Heteroecious
rust requires two distinct host species in order to complete its life cycle
Macrocyclic rust
produce other types of spores in addition to teliospores and basidiospores
Microcyclic rust
produce only teliospores and basidiospores
Rhizomorph
Mycelia produced in parallel arrangements to form thick branching strands, means of extending from depleted substrate to new food source
Wheat stem rust =Puccinia graminis
–Wheat is infected by aeciospores urediniospores, teliospores, basidiospores produced on wheat
–Barberry is infected by basidiospores, spermatia, aeciospores produced on barberry
Apple cedar rust =Gymnosporangium juniperi-virginianae•
–Apple is infected by basidiospores, spermatia, aeciospores produced on apple
–Cedar is infected by aeciospores teliospores, basidiospores produced on cedar
Corn smut = Ustilago maydis
basidiospores, teliospores
Covered smut of wheat = Tilletia caries
basidiospores, teliospores
Loose smut of wheat = Ustilago tritici
basidiospores, teliospores
Armillaria root rot = Armillaria mellea and other species
–Wide host range of mostly woody perennials
–Basidiospores
Rhizoctonia Diseases = Rhizoctonia solani (other species)
–Very wide host range
–No spores known or rare, 90 degree angle of branching hyphae
Southern blight = Sclerotium rolfsii
–Generally annual herbaceous crops and ornamentals
–No spores known or rare, round sclerotia
