Leaf diseases in cereals

Question 1

loss due to leaf spot diseases

Answer 1

10% in wheat crops 3% for barley

Question 2

Loss due to leaf spot disease wheat

Answer 2

residue is main source of infection because inoculum overwinters in stubble

Question 3

Cropping practices for leaf spot in wheat

Answer 3

minimum tillage direct seeding are more preferred

burring crop residue physically prevents inoculum reaching leaves

Question 4

damage caused by leaf spot in wheat

Answer 4

yield loss
seed shrivelling
seed discolouration
reduce quality

Question 5

leaf spot pathogens in wheat

Answer 5

pyrenophora- barley, wheat
septoria- wheat, barley, oats
cochliobous- wheat, barley, oats
stagonospora- wheat, oat
Phynchosporium- barley

Question 6

Tan spot wheat disease

Answer 6

oval shaped lesion on leaf with a tan spot on leaves
over winters in stubble
pseudothecia develop in spring

Question 7

septoria tritici blotch wheat

Answer 7

elongate grey brown lesions with black pycnidia resembling small dots develop

high precipitation increases it

Question 8

Spot blotch wheat

Answer 8

small dark spots on resistant varieties
large chlorotic blotches with dark centres on susceptible varieties

yes with high temp
severe in barley.
not as common in MB

Question 9

stagonospora modorum blotch Wheat

Answer 9

large irregularly sped tan coloured lesion
seed shrivelling
more common in high temp and rainfall

Question 10

speckled leaf blotch in barley

Answer 10

elongate grey brown lesions with black pycnidia as small dots

Question 11

control or management of diseases

Answer 11

a susceptible host, environmental conditions, a pathogen

Question 12

control or management of diseases. three protocols to break disease triangle

Answer 12

cultural
resisince
chemical

Question 13

leaf spot disease control

Answer 13

tillage, resistance, application of fungicides

Question 14

effects of tillage practices

Answer 14

don’t increase residue with wet weather because it will cause habit build up of stubble borne diseases. do conservation or no till

Question 15

chemical control

Factors effecting use of fungicide

Answer 15

variety susceptibility
level f disease in field 
weather conditions 
yield potential
market price

Question 16

cultivar selection

Answer 16

registered fro western provinces are susceptible

Question 17

Summary

Answer 17

Increased residues do not always lead to increased disease e.g. SNB
•Crop rotation may be effective way to control some diseases
•Start with clean seed (SNB)
•Select varieties with best disease package for your area (Manitoba Seed Guide)
•Know the value of your crop before applying fungicides

Question 18

More summary

Answer 18

Leaf spot diseases of cereals decrease yields and are detrimental to grain quality; producer $$ is impacted
•Numerous diseases ‘hit’ cereal crops in the prairies; their occurrence and severity will differ from region to region, and from year to year
•Diseases can be controlled by one, or a combination of, three main strategies; no single strategy may be 100% effective
•The deployment of effective resistance, when available, is the strategy of choice (see provincial Seed Guides)
•Diseases must be considered along with all other elements (fertilizer, weed control, tillage, rotations, markets, etc.) of overall crop production management