1. Wheat yield losses
due to rusts and
powdery mildew
presented
By
Dr. M. Abdelkader

2. Rust diseases of wheat and powdery mildew causes significant yield -
. losses
The damage caused depends upon the severity and time of infection -
. resulting into yield reduction
Estimates yield losses of cereals caused by rusts since 1918 are -
maintained by the United States Department of Agriculture
Research Service Cereal Disease Laboratory in St. Paul,
. Minnesota
Wheat stripe rust in the CWANA countries causing severe yield losses -
. more than 70% in 2010
leaf rust can cause grain yield losses higher than 50% in severe -
. epidemics
.In Australia stem rust cause losses up to 37% in 1992-
In 1995 wheat stripe rust caused yield losses ranged from 14 to 26% in-
. delta region in Egypt, while the national loss was about 10%
Wheat rusts under the Egyptian condition was the main cause to -
discarded some varieties such as Giza 139,144,150 sakha
. 8, 69, Gemmiza-1 and 5

3. Disease infection leads to
Missing
mplete damage to the economic - plants
(damping –off,
part ( loose smut
wilt(
al damage to the economic part -
No
(covered smut
yield
age to the other parts (down -
mildew, powdery mildew, leaf spot
and rusts

4. Yield losses estimation
(Total yield ( yield per plot-
.(Single plant (gm-
.(Kernel weight (gm- 1000-
Test weight-
Yd
Loss % =1- ------- x100
Yh
Where: Yd = yield of diseased plants
(.Yh = yield of healthy plants (Calpouzos et al., 1976

5. Factors Affecting Yield Losses
(.Varietal susceptibility (S-Ms-Mr-R- 1
(. Time of disease appearance (which growth stage- 2
Environmental conditions( temperature and- 3
(.relative humidity
For good experimental yield losses
.Using fungicides to protect the control plots- 1
.Inoculation at different dates- 2
.Inoculation with different inoculum level- 3
.Host predisposition- 4

6. Why we do
estimate
Yield loss
To estimate the Economic
Significance of the disease
To determine the economic
By
Threshold at which the To evaluate the genetic
Relating the disease
control measurement is Level of resistance in
infection
applied A variety
To yield loss

7. Relationship between stem rust severity, wheat
.growth stage, and percentage of yield loss
Boot Flower Milk Early Late Ripe %
dough dough Yield
loss
- - - - trace 5 0.0
- - - trace 5 10 0.5
- - trace 5 10 25 5.0
- trace 5 10 25 40 15.0
trace 5 10 25 40 65 50.0
5 10 25 40 65 100 75.0
10 25 40 65 100 100 100.0
(Roelfs (1992

8. Relationship between leaf rust severity, wheat
.growth stage, and percentage of yield loss
Pre- Jointing Boot to Flowerin Milk Early %
tillering heading g dough Yield
loss
- - trace 10 25 40 1
- trace 10 25 40 40 3
trace 10 25 40 65 65 10
10 25 40 65 100 100 20
25 40 65 100 100 100 35
40 65 100 100 100 100 50
100 100 100 100 100 100 95
(Chesters (1946

9. infected
One pustule seeds Healthy seeds
One pustule
100 grain samples
spores 10000 spores 3000

10. Yield Losses due to stem rust
infection
grain weight 1000 grain weight 1000
2009/2010 2010/2011
Cultivar
Disease (Inf. (gm Prot. Reduction Disease (Inf. (gm Prot. Reduction
severity ((gm % severity ((gm %
Sakha 8 S5 27 .40 40.40 0.321 S 20 39.11 43.17 9.4
Giza 160 S 20 38.19 42.47 10.07 S 20 28.07 34.58 18.82
Giza 164 S5 38.46 40.83 5.8 S 10 30.38 34.33 11.50
Gemmiza 3 Tr S 40.05 40.26 0.521 S5 50.35 o4.52 0.363

11. Yield Losses due to leaf rust
infection
grain weight 1000 grain weight 1000
2009/2010 2010/2011
Cultivar
Disease (Inf. (gm Prot. Reduction Disease (Inf. (gm Prot. Reduction
severity ((gm % severity ((gm %
Gemmeiza-7 S 80 43.238 48.656 11.135 S 80 40.119 48.328 17.138
Gemmeiza-10 S 70 40.258 45.047 10.631 S 80 37.238 45.656 18.240
Gemmeiza-11 S 70 52.059 54.328 4.176 S 70 51.332 54.257 5.391
Sakha-93 S 80 41.895 47.776 9.815 S 80 39.477 46.089 14.346

12. Yield Losses due to stripe rust
infection
grain weight 1000 grain weight 1000
2009/2010 2010/2011
Cultivar
Disease (Inf. (gm Prot. Reduction Disease (Inf. (gm Prot. Reduction
severity ((gm % severity ((gm %
Gemmeiza-5 S 30 32.00 41.677 23.21 S 20 46.72 51.12 8.6
Sakha-8 S 50 27.123 42.5 36.18 S 40 37.36 43.55 14.21
Sakha-69 S 40 28.79 42.460 32.19 S 30 31.332 45.257 30.07
Giza-160 S 80 25.541 42.776 39.112 S 50 32.7 42.54 23.13

13. Yield Losses due to Powdery
mildew infection
Cultivar grain weight 1000
2010/2011
Disease (Inf. (gm (Prot. (gm %Reduction
%severity
Gemmeiza-7 40 34.11 37.733 9.59
Gemmeiza-10 90 28.373 34.07 16.72
Sakha-93 50 34.09 37.77 9.73
Giza-160 60 26.893 31.2o 13.81

14. How to reduce wheat yield losses
Planting Resistant
Varieties
.Agriculture Practes
Yr 9
Ug99 New races
Yr27
. Sowing Dates-1
. Sowing Density-2
.Irrigation- 3 Tolerant Varieties-1
fertilization-4 Slow Rusting Varieties-2

15. Thank You

16. Rust diseases of wheat and powdery mildew causes significant yield -
. losses
The damage caused depends upon the severity and time of infection -
(. resulting into yield reduction (S. Ahmad et al., 2010
Estimates of yield losses of cereals caused by rusts since 1918 are -
maintained by the United States Department of Agriculture
Research Service Cereal Disease Laboratory in St. Paul,
(. Minnesota (Chen et al., 2004
Wheat strip rust in the CWANA countries causing severe yield losses -
. more than 70% in 2010
leaf rust can cause grain yield losses higher than 50% in severe -
(. epidemics (German et al. 2007
. In Australia stem rust cause losses up to 37% in 1992-
In 1995 wheat strip rust caused yield losses ranged from 14 to 26% in -
delta region in Egypt, while the national loss was about 10%
(. (El- Daoudi et al., 1996
Wheat rusts under the Egyptian condition was the main cause to -
discarded some varieties such as Giza 139,144,150 sakha
. 8, 69, Gemmiza-1 and 5