1. Efficacy of sterol-inhibiting fungicides and SAR chemicals for control of black root rot of cotton in the absence and presence of nematodes
Harun Toksoz

2. Outline Black root rot Sterol-inhibiting fungicides & SAR chemicals
Objective
Materials and methods
Results
Conclusions

3. Black Root Rot Caused by Thielaviopsis basicola
Found in almost all major production areas
Pathogen has a host range of more than 230 species
Rarely kills plants
Causes stunting
Results in less vigorous plants
Delays flowering
Reduces yield

4. Sterol-inhibiting fungicides and SAR chemicals
Myclobutanil and triadimenol
Triadimenol (Arthur, 1991)
Myclobutanil (Butler et al. 1996)
Bion (Acibenzolar-S-methyl)
Mondal et al. 2005

5. Effect of Bion on Disease Severity and Shoot Height
(Mondal et al. 2005)

6. Objective
Evaluate the efficacy of sterol-inhibiting fungicides and SAR chemicals alone and in combination on black root rot.
Systhane (Myclobutanil)
Bion (Acibenzolar-S-methyl)

7. Materials and Methods Artificially infested experiments
Controlled environmental experiments
Naturally infested experiments
Field experiments

8. Artificially Infested Experiments
Controlled environmental experiments
15 °C night
24 °C day
14 h daylight period
Infested with
M. incognita (16 eggs per g soil)
T. basicola (100 chlamydospores per g soil)
Both pathogens
None
15 different seed treatments
Terminate 28 DAP
2 experiments

9. Naturally Infested Experiments
1. Controlled environmental experiments
7 different treatments
4 replications
3 different soils
2. Field experiments
11 different treatments

10. Data Collection Disease assessments % Root discoloration (0-10)
Hypocotyl discoloration (1-4)
Galling (on root system and tap roots)
Percent colonization (0-10) / incidence

11. Results Artificially infested experiments
Naturally infested experiments
Controlled environmental experiments
Field experiments

12. Effect of seed treatments, artificially infested soil
Root Discoloration
Untreated
5.40 A
Dynasty CST
4.91 BA
Dynasty CST + Systhane
3.12 CDE
Dynasty CST + Bion
3.80 DCB
2.66 E
3.20 CDE
Dynasty Avicta Systhane
2.00 E
Dynasty Avicta Bion
3.72 BCD
3.83 BCD
3.41 DE
Dynasty Avicta
4.51 ABC

13. Effect of seed treatments, naturally infested soil; Tb+RN
RDI
Seed treatment
3.75 A
Systhane
2.87 B
Systhane (2x) + Avicta
2.94 B
Systhane Avicta Bion (0.6)
2.36 B
Systhane Avicta Bion (1.0)
2.31 B
Systhane (2x) + Avicta Bion (0.6)
1.26 C
24 ppg

14. Effect of seed treatments, naturally infested soil; Tb+RKN
RDI
Seed treatment
5.66 A
Systhane
5.00 A
Systhane (2x) + Avicta
4.82 A
Systhane Avicta + Bion (0.6)
5.28 A
Systhane Avicta + Bion (1.0)
5.25 A
Systhane (2x) + Avicta + Bion (0.6)
5.27 A
113 ppg

15. Effect of seed treatments, naturally infested soil; Tb+RKN
Node
Seed treatment
1.45 B
Systhane
1.75 A
Systhane (2x) Avicta
Systhane Avicta Bion (0.6)
1.91 A
Systhane Avicta Bion (1.0)
1.88 A
Systhane (2x) Avicta Bion (0.6)
Soil 3: 113 ppg

16. Effect of seed treatments, field experiment 2007
RDI
Seed treatment
4.60 a
Systhane
4.50 a
Systhane (2x) + Avicta
3.73 a
Systhane Avicta Bion (0.6)
4.17 a
Systhane Avicta Bion (1.0)
4.00 a
Systhane (2x) Avicta Bion (0.6)
4.33 a
Systhane (2x) Avicta Bion (1.0)
3.77 a
Systhane Temik
4.27 a

17. Effect of seed treatments, field experiments
Incidence
Seed treatment
88.0 a
Systhane
60.0 b
Systhane (2x) Avicta
57.3 b
Systhane Avicta Bion (0.6)
Systhane Avicta Bion (1.0)
52.0 b
Systhane (2x) Avicta Bion (0.6)
62.7 ab
Systhane (2x) Avicta Bion (1.0)
53.3 b
Systhane Temik

18. Effect of seed treatments, field experiments
Galling
Seed treatment
3.27 a
Systhane
2.73 ab
Systhane (2x) + Avicta
1.83 cd
Systhane Avicta Bion (0.6)
2.13 bc
Systhane Avicta Bion (1.0)
2.10 bc
Systhane (2x) + Avicta Bion (0.6)
2.03 bc
Systhane (2x) + Avicta Bion (1.0)
1.97 bcd
Systhane Temik
1.13 d

19. Conclusions Sterol-inhibiting fungicides are effective
Bion is effective
Population of pathogen
Plant growth, incidence…