Term
|
Definition
Kingdom: Stramenopila
Phylum: Oomycota
Species: P. aphanidermatum
P. debaryanum
P. irregulare
P. ultimum
P. myriotylum |
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Term
|
Definition
occur worldwide
affect seeds, seedlings, and older plants
most damaging to seeds/seedlings - cause pre- and postemergence damping off |
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Term
| Pythium disease cycle - asexual |
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Definition
mycelium
zoosporangium
vesicle
zoospores w/flagella
germ tube
chlamydospores |
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Term
| Pythium disease cycle - sexual |
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Definition
oogonium
antheridium (male nuclei)
oospore (zygote, resting spore) |
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Term
| Common names of Pythium diseases |
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Definition
Pythium root rot
Browning root rot
Pythium blight
Pythium cottony leak
Pythium seed rot
Pythium disease
Pythium stalk rot |
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Term
|
Definition
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Term
| Pythium disease development |
|
Definition
Pythium invades by direct penetration or entering natural cracks
Once inside seedlings, the pathogen continues to invade tissues by mechanical pressure and by producing enzymes that degrade the middle lamella
Older plants are more resistant and Pythium may be restricted to the root tips and young cells |
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Term
| Pythium - effects of environment |
|
Definition
Disease is more severe
When soil moisture is too high
When soil temperature is either too low or too high for the developing plant
With monoculture
With excess nitrogen |
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Term
| Pythium control - chemical |
|
Definition
Seed or bulb treatment: thiram, chloranil, captan, dichlone, ferbam, diazoben
applied to soil (in come cases seed): mefanoxam, metalaxyl, propamocarb, benzimidazoles, acylalanine, some copper products, fosetyl-Al, pyraclostrobin, cyazofamid, strobilurin
surfactants (hydroponics systems) |
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Term
| Pythium control - biological |
|
Definition
Primastop (Gliocladium catenulatum; ornamental, vegetable, and tree crops)
RootShield, Plant Shield, T-22 Planter Box (Trichoderma harzianum Rifai strain KRL-AG2; trees, shrubs, transplants, ornamentals, cabbage, tomato, cucumber)
SoilGard (Trichoderma virens; ornamental and food crops grown in greenhouses, nurseries, homes and interiorscapes)
YieldShield (Bacillus pumilus GB34; soybean) |
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Term
| Pythium control - cultural |
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Definition
| soil sterilization, maintain good soil drainage, avoid excess nitrogen |
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Term
|
Definition
Kingdom: Stramenopila
Phylum: Oomycota
P. cactorum (apple, lily, clover)
P. capsici (pepper, carrot, pumpkin, cucurbits, eggplant, tomato)
P. cambivora (trees)
P. cinnamomi (> 1,000 hosts)
P. citrophthora (citrus)
P. cryptogea (tomato, calla lily)
P. fragariae (strawberry)
P. megasperma (crucifers, cabbage, potato, etc.)
P. megasperma var. sojae (soybean)
P. nicotianae (tobacco) |
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Term
| Phytophthora disease cycle |
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Definition
Overwinters as oospores (zygote), chlamydospores (asexual resting structure), or mycelium in infected roots
Oospores and chlamydospores germinate to form a germ tube, which forms a mycelium or a sporangium with zoospores
Mycelium may also produce a sporangium with zoospores
Zoospores infect roots |
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Term
| Phytophthora diseases - common names |
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Definition
Phytophthora root rot
Phytophthora stem rot
Phytophthora blight
Buckeye fruit rot |
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Term
| Phytophthora - effects of environment |
|
Definition
Disease is more severe
When soil moisture is high
When temperatures are between 15 and 23ºC |
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Term
|
Definition
Genetic – plant resistant cultivars when available
Chemical - fungicides: metalaxyl, fosetyl Al, ethazol, propamocarb, strobilurins
Cultural - resistant cultivars, soil sterilization, good soil drainage, tree bark mixes and composted mixes for ornamentals
Biological - nothing that is effective |
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Term
|
Definition
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Term
|
Definition
Occur worldwide
May affect plants in all stages of growth, including seedlings and mature plants, and harvested products in transit or storage |
|
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Term
|
Definition
Sclerotinia sclerotiorum
S. minor
Both attack many succulent plants, mainly vegetables, flowers, and some shrubs
S. minor attacks primarily peanuts and lettuce
S. trifoliorum (forage legumes)
S. homeocarpa (turf grasses) |
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Term
| Sclerotinia disease cycle |
|
Definition
Sclerotia (overwintering structure)
Sclerotia germinate in spring to form slender stalks with an apothecium (sexual reproductive structure)
Apothecium contains asci with ascospores (product of meiosis)
Ascospores or mycelium from germinating sclerotia may infect plant tissue |
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Term
| Sclerotinia disease development |
|
Definition
Cottony white mycelial growth on infected plant
Large sclerotia (2 to 10 mm) appear
Brown lesions form at the base of stems
Foliage above the stem lesions wilt and die
Wet rot of fleshy fruits
Flower infections |
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Term
| Sclerotinia diseases - common names |
|
Definition
lettuce drop
Sclerotinia crown and stem rot
white mold |
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Term
|
Definition
Chemical - metham sodium (sprayed on soil); dichloran, thiophanate-methyl, iprodione, and vinclozolin (sprayed on plants)
Cultural - good soil drainage, adequate spacing, remove infected plants, rotate with a nonhost crop such as corn or small grains
Biological - work on mycoparasites of sclerotia
Coniothyrium minitans, available as Contans WG and Intercept WG
Trichoderma viride, T. virens
Gliocladium roseum
Sporodesmium sclerotivorum |
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Term
|
Definition
common name- take-all of wheat and cereals
Occurs worldwide in temperate regions
Root and crown rot of wheat, barley, and many other grasses
May attack the plant at any stage
Kills young seedlings, can cause severe yield losses in mature plants |
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Term
|
Definition
G. graminis var. tritici
attacks most cereals and grasses but not oats
G. graminis var. avenae
attacks all cereals including oats
G. graminis var. graminis
causes crown sheath rot of rice; most isolates are only slightly pathogenic on other cereals and grasses |
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Term
| Gauemmanomyces disease cycle |
|
Definition
G. graminis var. tritici
attacks most cereals and grasses but not oats
G. graminis var. avenae
attacks all cereals including oats
G. graminis var. graminis
causes crown sheath rot of rice; most isolates are only slightly pathogenic on other cereals and grasses |
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Term
| Gaeummanomyces disease development |
|
Definition
Infected seedlings are yellow and stunted
Infected plants produce few tillers and ripen prematurely, but the heads are white and do not contain grain
Roots are black and break off easily near the crown
Fungus extends from the roots up to the lower leaves
Thick brown strands of runner hyphae visible on the root surface |
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Term
|
Definition
Genetic – no cultivars available
Chemical - seed treatments are marginally effective (too expensive)
Cultural - crop rotation to a nonhost (except soybean), soil pH < 6.0, use ammonium-N, no plant resistance, but some tolerance
Biological - research on Pseudomonas, Bacillus, and Trichoderma spp. |
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Term
|
Definition
Occur worldwide in temperate and tropical regions
Armillaria spp. are among the most common fungi found in forest soils
Affects fruit trees, vines, shrubs, shade and forest trees, potatoes, and strawberries |
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Term
|
Definition
A. mellea
hardwoods and conifers, aggressive pathogen
A. ostoyae
conifers, aggressive pathogen
A. gallica (bulbosa)
pathogenic on stressed trees
A. tabescens
pathogenic on oak and orchard trees, very common in the southeast |
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Term
|
Definition
Overwinters as mycelia or rhizomorphs
Spreads by direct root contact or rhizomorphs
Can spread by basidiospores (product of meiosis) which colonize dead stumps and produce rhizomorphs
Basidiocarps (mushrooms), site of basidiospore production, are produced at the base of dead or dying trees |
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Term
| Armillaria disease development |
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Definition
Infected trees are smaller, have reduced growth, and yellowish leaves
Twig and branch dieback
Gradual or sudden death of trees
White fan-shaped mycelial mats appear on bark and roots of infected trees
Reddish brown to black rhizomorphs appear on roots and under bark |
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Term
|
Definition
Control of Armillaria usually not attempted in a natural forest
Cultural - remove infected stumps, avoid planting hosts in reclaimed forest land for several years, match species with site selection to avoid environmental stress, dig trench around infected trees in orchards
Chemical - fumigation of specific sites with methyl bromide, chloropicrin, or carbon disulfide after removal of infected tree
Biological - work with Trichoderma spp |
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Term
| Phymatotrichopsis root rot |
|
Definition
Phymatotrichopsis omnivora (asexual; confusion about the sexual state; linked to both basidiomycetes and ascomycetes)
Host range includes >2,000 species of dicots
Primary economic host is cotton
One of the most destructive pathogens known |
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Term
| Disease cycle of P. omnivora |
|
Definition
Three growth or reproductive stages:
mycelial and rhizomorph or strand
sclerotial
conidial |
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Term
| Disease cycle of P. omnivora - primary |
|
Definition
Primary inoculum - rhizomorph or sclerotia that have overwintered
Sclerotia germinate and rhizomorphs grow through soil until they contact a root. They then wrap around the root and grow upward toward the soilline where the roots are killed.
New sclerotia form in chains on the roots, or in masses |
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Term
| Disease development - P. omnivora |
|
Definition
Infection results from enzymatic and mechanical action of the pathogen
Mycelium enters root and spreads through the periderm, phloem, and cambium
Fungus eventually enters the xylem and produces vascular occlusions |
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Term
| Effects of environment on P. omnivora |
|
Definition
High sodium content in clay soils is unfavorable
Fungus is most destructive when temperatures are high, moisture is adequate and soil pH is about 7.0
Fungus cannot withstand freezing temperatures |
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Term
| P. omnivora - cultural controls |
|
Definition
Crop rotation with cereals
Plant early maturing cotton cultivars
Weed control
Deep plowing (causes erosion problems)
Addition of sodium chloride (?) |
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Term
|
Definition
Rotting of seeds, roots, stems, crowns, corms, bulbs, and tubers; damping-off of seedlings
Occurs worldwide
Affects many different plant families (vegetables, flowers, field crops, weeds)
Reduction in stands, growth, and yield |
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Term
| Root and stem rots - Fusarium |
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Definition
Fusarium solani (main species)
F. oxysporum can be involved |
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Term
|
Definition
Fusarium solani produces asexual spores (microconidia and macroconidia)
Sexual state = Nectria haematococca (Ascomycete)
Produces chlamydospores
Overwinters as mycelium or spores in infected or dead tissues or seed
Spread by air, equipment, or water |
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Term
| Fusarium disease development |
|
Definition
Infected roots are dark red to brown
Cracks form along main root; secondary roots are killed
Infected plants are stunted and die with or without wilt symptoms
Pink or reddish lesions on stem at or below soil line
Rots of tubers, corms, and bulbs are dry and firm |
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Term
| Fusarium - effects of environment |
|
Definition
Disease is more severe when plants are stressed by
Low temperature
Drought or excessive water
Herbicides
Soil compaction
Subsurface tillage pans |
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Term
|
Definition
Cultural – Losses can be reduced in the field by
Loosen compacted soil with subsoiler chisels (reduces soil moisture)
Crop rotation with nonhost
Maintain good soil drainage
Plant disease-free seed
Fertilize with nitrate-N
Genetic
Resistant cultivars when available
Chemical- soil sterilization in greenhouse crops; fungicide sprays can reduce field losses – look for products labeled for specific crops
Biological- Companion, Deny, HiStick N/T, Intercept, Kodiak, Mycostop, Primastop, Rootshield, Plant Shield, T-22 Planter box, and YieldShield |
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Term
|
Definition
Occur worldwide
Disease severity favored by warm climates and warm soil temperatures
Affects annual vegetables and flowers, field crops (cotton, tobacco), herbaceous perennial ornamentals, plantation crops (banana, plantain, coffee, sugarcane), weeds, shade trees, and mimosa tree |
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Term
| Fusarium vascular wilt species |
|
Definition
Fusarium oxysporum
Formae specialis = group of biotypes of a pathogen species that infect only plants within a certain host genus or species, e.g. F. oxysporum f. sp. lycopersici attacks tomato
Biotype = subgroup within a species that has one or more characteristics in common |
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Term
| F. oxysporum disease cycle |
|
Definition
Fusarium oxysporum f.sp. lycopersici
Overwinters in infected crop debris as mycelium, micro- or macroconidia, or chlamydospores
Wilt is favored by air temperature >28ºC, adequate soil moisture, low N and P, high K, low soil pH, short day length, low light intensity
Virulence enhanced with ammonium-N and decreased with nitrate-N |
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Term
| F. oxysporum disease development |
|
Definition
Stunting of seedlings, which wilt and die
In older plants, leaves turn yellow, often only on one side of plant
Plants wilt during hottest part of the day and recover
Wilting becomes more extensive and plants collapse and die |
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Term
| F. oxysporum disease development p. 2 |
|
Definition
Fungus enters root tips directly or through wounds
Fungus grows in cortex between cells, then enters xylem vessels through pits
Fungus remains in xylem vessels and travels upward by release of microconidia
Vessels are clogged, plant dies |
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Term
|
Definition
Cultural - resistant cultivars, soil pH of 6.5 to 7.0, fertilize with nitrate-N, avoid spreading pathogen, soil solarization
Biological - ongoing work with Pseudomonas, Trichoderma, and nonpathogenic F. oxysporum as biocontrol agents |
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Term
|
Definition
Occur worldwide
Affect > 200 plant species (annual vegetables and flowers, fruit trees, field crops, shade and forest trees) |
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Term
|
Definition
Verticillium albo-atrum
produces microsclerotial-like, dark, thick-walled mycelium
20 to 25ºC
Verticillium dahliae
produces microsclerotia
25 to 28ºC |
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Term
| Verticillium disease cycle |
|
Definition
V. dahliae overwinters as microsclerotia; both species overwinter as mycelium in the propagative organs of perennial hosts, or in plant debris
Fungus enters through wounds or penetrates directly
Fungus is spread by contaminated seed, cuttings, wind, flooding, and soil |
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Term
| Verticillium disease development |
|
Definition
Symptoms similar to Fusarium wilt; differences are Verticillium causes disease at lower temperatures, symptoms develop more slowly and appear on lower or outer part of plant
Older plants are often stunted and vascular tissue is discolored
Gradual wilting (branches die) or abrupt collapse (plant dies) |
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Term
|
Definition
| Cultural - resistant cultivars, soil solarization |
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Term
| Thielaviopsis black root rot |
|
Definition
Black root rot and damping-off of vegetables, flowers, and field crops
Occurs worldwide
Major symptom is discrete, black, necrotic lesions or coalescing lesions on root
Damage results from cortex breakdown and rotting of feeder roots
Cool weather disease |
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Term
|
Definition
Thielaviopsis basicola (plant pathologists)
Chalara elegans (mycologists) |
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Term
| Thievaliopsis disease cycle |
|
Definition
Nonreproductive hyphae (no spores produced) are colorless
Pigmented hyphae produce asexual spores (C. elegans endoconidia – colorless, cylindrical)
Dark chlamydospores produced in chains (T. basicola) and are the overwintering structure
Hyphae from germinating chlamydospores or endoconidia penetrate root hairs and progress to endodermis (no further invasion) |
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Term
| Thievaliopsis disease development |
|
Definition
Hosts can be attacked at any age and severely infected seedlings usually die
Older plants are stunted and on hot days the plants wilt more quickly
In diseased tissue, dark chlamydospores will be visible with a microscope
Disease is favored by cool, wet, alkaline soils |
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Term
|
Definition
Cultural
Rotations with monocots
Maintain soil pH near 6.0
Chemical
Sterol inhibitor fungicides (triazoles)
Genetic
Resistant cultivars are available in some crops |
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Term
|
Definition
Occur worldwide
Affects annual vegetables and flowers, field crops, turf grasses, perennial ornamentals, shrubs, and trees
Symptoms vary with host, age of host at infection, and environmental conditions |
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Term
|
Definition
Rhizoctonia solani
wide host range
R. zeae
corn, rice, millet, pine seedlings, legumes, turf grasses
R. oryzae
rice, corn, sorghum, cereals, turf grasses
Binucleate Rhizoctonia spp.
strawberry, vegetables, rice, millet, cereals, turf grasses, soybean, pine seedlings, azaleas |
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Term
| Perfect stage (teleomorph) of Rhizoctonia spp. |
|
Definition
Perfect (sexual) stage can also cause disease
Ceratobasidium
Thanatephorus
Tulasnella
Waitea |
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Term
| Characteristics of R. solani |
|
Definition
Right angle branching hypha with a constriction at point of attachment of branch to main hypha
Brown to black loosely formed sclerotia |
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Term
| Anastomosis groups of Rhizoctonia |
|
Definition
Strains are separated on the basis of anastomosis groups
Anastomosis = fusion of touching hyphae; represents vegetative compatibility groups
Anastomosis groups represent genetic isolation of populations and groupings are somewhat host specific |
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Term
| Rhizoctonia disease cycle |
|
Definition
Overwinters as mycelium or loosely-formed brown to black sclerotia in soil and infected plant material
With high humidity and moderate temperatures, T. cucumeris may form as a mildew-like growth on soil and plant near the soil line
Disease is severe when soil is moderately wet and air temperature = 15-18ºC |
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Term
| Rhizoctonia disease development |
|
Definition
Damping-off of seedlings
Older plants:
Stem canker or soreshin at soil line
Root lesions girdle the root which is eventually rotted through leaving a spear tip appearance
Reddish brown sunken lesions on lower leaves
On turf grass, only the leaves are killed (brown patch appearance)
On potato, hard black sclerotia form on the tuber surface
Thanatephorus cucumeris (sexual stage) causes necrotic lesions on leaves of tobacco (target spot) |
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Term
|
Definition
Cultural - plant on well-drained soil, adequate spacing between plants, tillage
Chemical - Soil drenches with PCNB, drenches on soil or seedlings with chlorothalonil, thiophanate methyl, or iprodione
Biological - work with Pseudomonas, Trichoderma, Gliocladium, Laetisaria, and Bacillus |
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Term
|
Definition
Occur worldwide in warm climates
Affect vegetables (carrot, celery, crucifers, eggplant, lettuce, okra onion, peppers, tomato), flowers, cereals, field crops (cereals, peanuts, cotton, tobacco), forage plants, and weeds
Symptoms: seedling damping-off; stem cankers; rot of crowns, roots, tubers, bulbs, and fruits |
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Term
|
Definition
Sclerotium rolfsii
perfect stage = Aethalia (basidiomycete)
S. cepivorum |
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Term
| Sclerotinium disease cycle |
|
Definition
Overwinters as sclerotia
Fungus kills and disintegrates tissue directly by producing oxalic acid; fungus also produces pectinolytic and cellulolytic enzymes
Fungus attacks at soil line
Disease is severe when soil moisture is high and air temperature = 30 to 35ºC |
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Term
| Sclerotinia disease development |
|
Definition
Infected seedlings are killed quickly
Older plants:
Fungus grows into the cortex and girdles the stem at the soil line (dark brown lesion on stem)
Lower leaves turn yellow and wilt
Fungus progresses up the stem and down to the roots
Older plants:
Fungus grows as a white mycelium on the soil surface to infect the next plant
Small, round sclerotia that are at first white, then become dark brown to black, are produced on infected tissue |
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|
Term
|
Definition
Cultural - crop rotation with a nonhost (corn, wheat), deep plowing to bury sclerotia, using ammonium-N fertilizers, and soil solarization
Chemical - Soil drenches with PCNB, captafol, and dichloran
Biological - work with Pseudomonas, Trichoderma, and Streptomyces |
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Term
| Characteristics of Ralstonia solanacearum |
|
Definition
Gram-negative rod, aerobic bacterium
Motile (1 or more polar flagella)
Not fluorescent
Mutates readily in culture
Pathogenic colonies opaque, no flagella |
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Term
| Environment needed for Ralstonia |
|
Definition
Minimum growth temperature = 10°C
Max. temperature = 41°C
Formerly classified in Pseudomonas, then Burkholderia, now in Ralstonia
Can survive in soil without host tissue |
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|
Term
| Diseases caused by R. solanacearum |
|
Definition
Causes wilt of several hundred plant species (tobacco, tomato, potato, pepper, eggplant, peanut, soybean, banana)
Occurs worldwide (warm climates)
Not unusual for 100% of a solanaceous crop to be killed in the field by this pathogen |
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|
Term
| Common disease names - Ralstonia |
|
Definition
Southern bacterial wilt (or bacterial wilt) of vegetables
Granville wilt of tobacco
Moko disease of banana
Brown rot of potatoes |
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|
Term
|
Definition
Race 1 - common in the USA on solanaceous crops and weeds, peanuts, soybeans, diploid bananas
Race 2 - triploid bananas, Heliconia spp.
Race 3 - potato, tomato, weakly pathogenic on tobacco (not in USA)
Race 4 – ginger, found in Asia
Race 5 - Mulberry (from China) |
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Term
| R. solanaceum disease symptoms |
|
Definition
Yellowing, stunting, dwarfing, development of adventitious roots, wilting
Infected young plants die quickly
In older plants, wilting of the youngest leaves or only on one side may occur first, followed by irreversible wilting
Discolored vascular tissue and bacterial ooze |
|
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Term
|
Definition
Ralstonia solanacearum can survive in soil without host tissue, and can survive in diseased plant tissue, seeds, tubers, and weed hosts
Wound parasite; injury (usually roots) is essential for infection
After entering a wound, the bacteria reach the large xylem vessels and produce pectolytic enzymes and cellulases
Cavities filled with bacteria are created inside the plant
Bacterial wilt does not occur in areas where the mean temperature is less than 10°C
Disease does not develop until temperature is greater than 20°C
May occur in any soil type or soil pH |
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|
Term
| Ralstonia controls - cultural |
|
Definition
Exclusion
Crop rotation or fallow
Steam treatment of soil
Soil solarization
Plant disease-free planting materials
Control root-chewing insects and nematodes
Plant crops early
Practice sanitation |
|
|
Term
| Ralstonia controls - noncultural |
|
Definition
Genetic
Resistant cultivars (for some plants)
Biological
Research with antagonistic bacteria and nonpathogenic R. solanacearum
Chemical
Fumigation of soil with chloropicrin |
|
|
Term
| Macrophomina – Charcoal rot |
|
Definition
Occurs worldwide
Large host range (more than 500 plant species)
May affect young and mature plants
Causes seed and seedling rots, wilt, rots of roots, stems, stalks, and pods, and leaf spot |
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|
Term
|
Definition
One species:
Macrophomina phaseolina
Asexual fungus
There are many synonyms |
|
|
Term
| Macrophomina disease cycle |
|
Definition
Microsclerotia (overwintering structure) – black, vary greatly in size, shape and surface texture
Pycnidia – produced by some isolates, structure that is immersed in host tissue and erupts; contains conidiophores that produce thousands of single-celled conidia
Overwintering microsclerotia and resting mycelium, found in dry soils and embedded in plant residues, germinate on the surface of roots to form germ tubes
Fungus can persist for up to 3 years and is also seedborne
Germ tubes penetrate and cause infection |
|
|
Term
| Macrophomina disease development |
|
Definition
Macrophomina restricts water movement in the plant by mechanical plugging of the water-conducting vessels with mycelium and microsclerotia
Fungus secretes toxins and enzymes that kill host tissues
Fungus does not survive well in wet soils (microsclerotia may last 7-8 weeks, mycelium lasts a few days)
Disease development and symptom expression are most rapid at temperatures of 82 to 95°F (28 to 35°C) – hot, dry conditions promote disease |
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|
Term
|
Definition
Plant high-quality, certified, disease-free seed
Plant seeds at the recommended rate. Over-crowding makes seedlings more susceptible to infection.
Fertilize, based on a soil test
Rotate to non-host crops (cereals) for 1-3 years, depending on crop
If possible, irrigate during extended periods of hot, dry weather
Plow down/ remove infected crop residue (if erosion is not a problem). This leaves sclerotia in soil where they are more subject to attack by other soil microorganisms.
No effective fungicides available |
|
|
Term
|
Definition
Ascomycete, related to Gaeumannomyces; produces asexual spores also; Taxonomy uncertain
Hosts are mainly members of Poaceae (barley, millet, rice, wheat, turfgrasses, grass weeds)
Worldwide –found wherever hosts are grown
Infects foliage and roots
Causes seed and seedling rots, wilt, root rot, and leaf spot |
|
|
Term
|
Definition
Five species:
Magnaporthe grisea (rice blast disease and other cereals)
M. oryzae (blast disease of rice and other cereals)
M. poae (summer patch of turfgrass)
M. rhizophila (cereals, grasses)
M. salvinii (stem rot of rice) |
|
|
Term
| Magnathorpe disease cycle |
|
Definition
Hyphae in dead plant tissue, previously colonized by the fungus (overwintering stage) comes in contact with healthy roots
Invades vascular tissue
Sexual stage can be formed (perithecia with ascospores)
Asexual spores formed, serve to spread the pathogen to aerial regions |
|
|
Term
| Magnathorpe disease development |
|
Definition
Fungus enters the plant either through the cuticle or via stomata
Latent periods require 4 - 6 days at optimal temperatures (24-28°C)
At RH >93%, conidia are produced within 6 days after germination
Blast is a polycyclic disease, with 7 - 8 cycles per year in temperate environments, compared with 10 - 15 cycles per season and 2 - 3 seasons per year in tropical environments |
|
|
Term
|
Definition
Plant resistant cultivars
Avoid excess fertilizer
Optimize water management
Chemical seed treatments
carpropamid, probenazole, tricyclazole, pyroquilon
Foliar chemical treatments
phosphorothiolates, strobilurins, melaninbiosynthesis-inhibitors, kasugamicin, blasticidin |
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| Gaeumannomyces life cycle |
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