Week 10 Introduction to Cereal Disease Control 2024 Flashcards
Fungal Diseases - Infections over the season
1- Seedling Diseases:
2- ‘Seed’ diseases
3- Stem diseases
4- Root diseases
5- Leaf diseases
6- Ear diseases
1* Seedling diseases
– Michrodocium nivale (fusarium)
2* ‘Seed’ diseases
– loose smut, Bunt (covered smut)
3* Stem diseases - eyespot, sharp eyespot
4* Root diseases - take-all
5* Leaf diseases - mildew, rusts, septoria sp.,
rhyncosporium, net blotch, etc
6* Ear diseases - fusarium sp., sooty moulds
Key Diseases for each cereal crop
Wheat:
7
- Take-all
- Septoria tritici
- Mildew
- Ear Fusarium
- Eyespot
- Yellow rust
- Brown rust
Key Diseases for each cereal crop
Barley
5
- Rhyncosporium
- Net blotch
- Mildew
- Brown Rust
- Ramularia (leaf blotch)
Key Diseases for each cereal crop
Oats
2
- Mildew
- Crown rust
Powdery Mildew
1- Whats it most common in?
2- Whats it look like?
3- At the end of season what does it show?
4- Wind dispersed conidia is ideally what?
1-Commonest of cereal
diseases
2- Very distinctive symptoms
Chlorotic flecks
Distinctive white fluffy
pustules
Older pustules – grey/brown
3- End of season – shows as
black cleistothecia
4- Wind dispersed conidia –
ideally with 15-20 C / high
Slide 5 and 6 Life cycle of powdery mildew that im not learning :)
Yellow Rust
Puccinia striiformis
1- How is it distinctive?
2- Is it a parasite?
3- What weather does it favor?
4- What does it survive on?
1- Distinctive pustules in stripes
between leaf veins , foci
infections (hot spots)
2- Obligate parasite , and has many
specific races (sub-species) /
pathotypes
3- Favoured by cool humid weather
and very short latent period
4- Survives on volunteers , genetic
resistance is key (breeding progs)
diversification progs
Common diseases to each cereal crop , Fungal Diseases :
eyespot
take-all
What are more prominent in wheat?
– eyespot (wheat > barley)
– take-all (wheat > barley)
fusarium species (more prominent in wheat)
Important diseases in specific cereal crops
(2)
– Septoria sp. in wheat
– Rhyncosporium and Net blotch in barley
Fungal diseases and weather
Wet weather diseases (4)
– Septoria sp. in wheat
– Rhyncosporium and Net blotch in barley
– Fusarium species on the ear
– Sooty moulds / Botyritis
Fungal diseases and weather
Dry’ Weather Diseases (2)
– Mildew on all cereals
– Rust diseases
Methods of Disease Control (3)
1-* Cultural
– rotation (take-all, eyespot)
– ploughing
– stubble hygiene
2-* Varietial
– use of resistant varieties e.g. for BYMV (barley
yellow mosaic virus
– for foliar diseases, e.g. yellow rust, mildew
control
– use of varietial diversification
3-* Chemical
– seed dressing
– foliar fungicides
Cultural Control - objective
Whats the key objective?
Key objective is to reduce the incidence and severity
of the disease
To reduce the innoculum / initial infection level at the
beginning of the season
To delay the disease epidemic ( in relative terms )
– in late spring and early summer, GS 30 onwards
– to delay the disease progress curve in a high
disease season
– to reduce the disease severity on the upper canopy
late in the season
Cultural Methods of Disease
Control: (3)
1* Rotation
– excellent method for reducing take-all infection
– it is claimed a two-year break needed for eyespot
2* Stubble hygiene / good ploughing
– can be very useful for reducing net blotch
infection
– also very good for reducing Fusarium
graminarium (after Maize in USA/Germany)
3* Delayed Sowing
Genetic Resistance:
1- What is a key to good ICM programme?
2- Whats the focus usually on?
3- What gene can be venerable?
4- What will fall overtime?
Varietial Resistance Ratings
1 – Key to good ICM programme for disease control
– Ideally resistance rating of 7 plus
2- – Focus is usually on the more important foliar diseases
3– Major gene (single gene) resistance can be vulnerable so
multi-gene R is more desirable
4– Resistance will often fall over time as diseases
populations become more adapted to widely grown
varieties
