1. Application condition and performance of
glyphosate in Turkey
Prof. Dr. M. Nedim DOGAN
Adnan Menderes University, Faculty of Agriculture,
Dept. Plant Protection, Weed Science
AYDIN-TURKEY
mndogan@adu.edu.tr
A project supported by Monsanto

2. GLYPHOSATE IN TURKEY
Perennial crops
About 70 % of fruit growers in Aydin province use glyphosate
Roadsides, Railways, Irrigation channels and other non agricultural
areas
In cotton prior to harvest as desiccant
Many different formulations
Satisfactory effect against most weed species

3. GLYPHOSATE IN TURKEY
However, it is reported by Monsanto people from Turkey that
herbicide fails in controlling
• Sorghum halepense L. (Pers.) Johnsongrass
• Cyperus rotundus L. Purple nutsedge
• Portulaca oleracea L. Common purslane
• Convolvulus arvensis L. Field bindweed

4. What can be the reason ?
• Some problems concerning application and timing
OR
• Resistance

5. AIM of the project with Monsanto
• Formulation
• Spray water volume
• Spray water quality
• Weed growth stages
• Climatic conditions during application

6. Pot experiments were carried out in the screenhouse
Methods
of the weed science laboratory at Adnan Menderes
Pot experiments
University, Faculty of Agriculture, Turkey. Perennial
weeds were grown from rhizomes and P. oleracea
from seeds. A growing medium of turf: sand: perlit and
soil (1:1:1:1) was used for plant growth.

7. Rhizomes of S. halepense were planted in 3.8 l pots and
rhizomes of C. rotundus, C. arvensis and seeds of P.
oleracea were in 3.0 l pots.

8. Four different glyphosate formulations were used in all
experiments
Formulation Trade name Glyphosate
content
(g a.e./l)
MON 79376 Roundup Star 360
MON 79351 Not commercial yet 480
in Turkey
MON 78273 Cayenne 540
Generic Product Sonround 360

9. Glyphosate was applied at three doses
2160 g a.i./ha Recommended dose
1620 g a.i./ha 75 % of the recommended (25 % reduced)
1080 g a.i./ha Half dose (50 % reduced)

10. All herbicide treatments were done by using a spray chamber.
First the recommended doses of each formulation were
adjusted. Other doses were then obtained as water dilutions.

11. MODUL I.
Effect of water volume on the efficacy of glyphosate
•Water volume 200 and 600 l/ha
• 600 l/ha water volume was achieved by running 3 times
(each with 1/3 spilt dose)
•Experiments were carried out two times.
•Average plant heights at the beginning of the experiments
• Johnsongrass 25 and 22 cm, resp.
•Purple nutsedge 5-6 leaves.
•Common purslane 1-3 branches.

12. Relative fresh weights (%) of tested weed species as affected by water volume
Common Purple
Weed species Johnsongrass
purslane nutsedge
**
Experiment NS NS
I II
Water volume
200 600 200 600 200 600 200 600
(l/ha)
Untreated 100 100 100 100
1080 g a.i./ha (50 %) 8,7 b 37,1 a 1,6 b 18,0 a 34,2 a 41,4 a
1620 g a.i./ha (75 %) 4,5 a 15,7 a 0,3 a 1,9 a 15,6 b 26,0 a
2160 g a.i./ha NS
2,7 a 5,9 a 0,0 a 0,4 a 8,2 b 22,4 a
(recommended)
SEM 4,02 2,91 3,96
Formulation NS, Results are average of all formulations

13. Johnsongrass treated with
half dose of glyphosate in
200 l/ha volume
Johnsongrass treated with
half dose of glyphosate in
600 l/ha volume

14. 200 l/ha
600 l/ha

15. MODUL II
Effect of water quality on the efficacy of glyphosate
Jonhsnograss: 33,6 – 50 cm height
Common purslane: 2-4 branches
Purple nutsedge: 5-6 leaves
Three different spray water having different characteristics
• Clean soft water
•Clean hard water (CaCl2 added)
•River water (from Great Meander River)

16. 10.06.2011

17. Properties of spray water used in Experiments
Clean water Clean + CaCl2 River water
Total 1,12 21,84 22,40
Hardness (very soft) (hard) (hard)
(German)
pH 6,31 6,64 7,56
EC (µS/cm) 46 846 1008
K (me/l) 0,10 0,09 0,34
Ca (me/l) 0,10 7,35 2,37
Na (me/l) 0,19 0,23 3,58
Mg (me/l) 0,08 0,17 5,11

18. Relative fresh weight (%) of Sorghum halepense and Cyperus
rotundus as affected by spray water quality
Water quality S. halepense* C. rotundus**
Dose (g a.i./ha) 1080 1080 1620 2160
(50 %) (50 %) (75 %) (100 %)
Untreated control 100
Clean water 4,4 b 21,7 c 18,0 b 6,0 a
Clean water + CaCl2 5,4 b 43,1 b 24,9 ab 11,9 a
River water 63,8 a 73,0 a 30,7 a 13,6 a
SEM 2,33 4,23
Formulation NS, Results are average of all formulations

19. 1 2 3 4 1 2 3 4
1. Untreated
2. Clean soft water
3. Clean hard water
4. River water
1 2 3 4
Half dose 1 week after treatment

20. 1 2 3 4
1. Untreated
2. Clean soft water
3. Clean hard water
4. River water
1 2 3 4
Recommended dose 1 week after treatment

21. Effect of weed growth stage on the efficacy of glyphosate
•Water volume: 200 l/ha
•Growing weeds within different intervals
•Treatment at the same time
Growth stages
Early Middle Late
Johnsograss: 22 cm 40 cm 80 cm
Common purslane: 3-4 branches 5-6 branches flowered
Purple nutsedge: 3-4 leaves 6-8 leaves 13-14 leaves

22. Effect of weed growth stage on the efficacy of
glyphosate on Sorghum halepense
Relative fresh weight (%) of Sorghum halepense as affected by growth stage
Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)
Growth stage Early Middle Late Early Middle Late
Untreated 100 100
Glyphosate 0,8 b 3,9 b 19,7 a 0,8 b 3,0 b 17,4 a
SE 2,8

23. 11 22 33 44
1 2 3 4
Early Middle
22 cm 40 cm
1. Untreated
2. 1080 g
3. 1620 g
4. 2160 g
Late Half dose 2 weeks
1 2 3 4 after treatment
80 cm

24. Effect of weed growth stage on the efficacy of
glyphosate on Cyperus rotundus
Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)
Growth stage Early Middle Late Early Middle Late
Untreated 100 100
Glyphosate 100 a 43 b 88,9 a 53,6 a 3,7 b 36,8 a
SE 9,8
Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)
Growth stage Early Middle Late Early Middle Late
Untreated 100 100
Glyphosate 29,5 b 16,9 b 100,0 a 6,8 b 12,1 b 48,4 a
SE 7,1

25. 1 2 3 4 1 2 3 4
Early 3-4 leaf Middle 6-8
leaf
1. Untreated
2. 1080 g
3. 1620 g Recommended
4. 2160 g dose 3 weeks
after treatment
Late 10-13
leaf 1 2 3 4

26. Effect of weed growth stage on the efficacy of
glyphosate on Portulaca oleracea
Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)
Growth stage Early Middle Late Early Middle Late
Untreated 100 100
Glyphosate 2,7 c 25,0 b 52,9 a 1,4 c 23,1 b 49,8 a
SE 4,0
Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)
Growth stage Early Middle Late Early Middle Late
Untreated 100 100
Glyphosate 5,3 c 100,0 a 86,3 b 3,5 c 86,3 a 60,4 b
SE 9,0

27. 1 2 3 4 1 2 3 4
Early Middle
3-4 branches 5-6 branches
1. Untreated
Late Beginning of 2. 1080 g
flowering 3. 1620 g
4. 2160 g
Half dose 2 weeks
after treatment 1 2 3 4

28. RESULT
All investigated factors influenced the
performance of glyphosate on all weed species
Early growth stages, low water volume and
clean spray water affected the glyphosate
performance positively
Herbicide formulation was not important
Recommended dose provided in most cases
reliable weed control

29. Problem weeds reported by Monsanto people in Turkey
Johnsongrass:
Quite sensitive to glyphosate even at the larger growth stages.
Problems can be attributed to misapplications, low doses in
combination with wrong water volumes and low water quality
Common purslane:
Quite sensitive to glyphosate only at early growth stages, but
the sensitivity is lower as plants become older. Water volume
and quality affected the glyphosate performance on this weed
slightly
Problems can be associated with wrong application timings
(larger growth stages and/or low application doses

30. Purple nutsedge:
• Less sensitive than other two species, only recommended
dose with low water volume, good water quality and
suitable growth stages provide satisfactory weed control
•Problems can be associated with all investgated factors,
but still more investgations are needed to improve the
efficacy
Field bindweed: ???

31. Further Studies (Pot Experiments)
Effect of climatic factors during application time (time of day) on
glyphosate efficacy
In these experiments, interactions between the climatic conditions
during the application and glyphosate efficacy will be evaluated.
Herbicide treatments will be done in the morning early, during
midday and at the evening.
Temperature, humidity and light conditions will be recorded
Interactions among water volume, water quality, growth stages
and application time (time of day)

32. Further Studies (Field Experiments)
• Since results showed that purple nutsedge (C. rotundus) was
real problem, this weed will be aimed in field experiments
• Since it was not possible to work with field bind weed (C.
arvensis) in pot experiments, a field experiment will be also
conducted for this weed
• 2 glyphosate formulations X 2 water quality X 2 growth stages
X 2 application times (time of day) X 3 replications
• An experiment with C. arvensis has started on 11‐12th June
2011 in a fig orchard in Aydin ‐ Turkey

33. Significant thanks to Monsanto
for financial support
During field experiment, 10.06.2011

34. Thank you very much for your
attention