Chemical control of diseases of plants by mr Allah Dad Khan Visiting professor he University of Agriculture Peshawar Pakistan

2. Chemical Control of
Diseases of Plants
By
Allah Dad Khan

3. Chemical Control
1. Protectant chemical
2. Eradicate chemical
3. Chemotherapeutants

4. Methods of Application
1. Spraying
2. Dusting
3. Fumigation

5. Merits of Spraying
1. Less cost of active ingredients per unit
2. Good coverage/deposition
3. Residual effect for more
4. Can spray in high wind velocity ( till 10 mile/hr)
5. Drop size can adjust
6. Better utilization of chemical & can reduce drift loss

6. Demerits of Spraying
1. More time & labour
2. Sprayers are heavy
3. Sprayers are costly
4. Have to prepare before use
5. Storage problem
6. No spraying in moist weather

7. Seed Treatment
1. Seed disinfectants
a. internally seed borne
b. Exp. Vitavax, Carbedazim
2. Seed disinfectants a. externally seed borne b. Exp. Copper carbonate
3. Seed protectants a. soil borne pathogen b. Exp. Thiram, Captan

8. Methods of Seed
Treatment
1. Dry seed dressing/ treatment
2. 2. Slurry treatment
3. Seed dip method 4. Planter hopper box seed treatment

9. Methods of Soil
Treatment
1. Soil drenching
2. Broadcasting of dust, powder or granules
3. Furrow application
4. Spot application
5. Strip application
6. Pits application
7. Plantation site application

10. Fungicides
Fungicide Latin word Fungus + caedo (to kill) “Fungicide
has been defined as a chemical substance which has the
ability to prevent damage caused by fungi to growing crops
and their products”

11. Classification of
Fungicides
(A). On the basis of chemical nature
(1). Protectants- Exp - Thiram Create a barrier b/w plant &
pathogen
(2). Eradicants- Exp- Tilt Remove the pathogen from
infection court
(3). Systemic & Non Systemic- Exp. Contaf

12. Classification of
Fungicides
(B). Base on the General Use
(1). Seed protectant – Exp. Thiram
(2). Soil Fungicide – Exp. Captan
(3). Foliage & Blossom Protectant – Exp. Ferbam
(4). Fruit Protectant- Exp. Captan
(5). Tree Wound Dressing- Exp. Bordeaux Mixture

13. Classification of
Fungicides
(C). Base on the Chemical Nature
(1). Sulphur compounds
(2). Copper Compounds
(3). Mercury Compounds
(4). Quinones
(5). Aromatic Compounds
(6). Heterocyclic Compounds
(7). Organotin Compounds
(8). Benzimidazoles
(9). Oxanthins
(10). Others

14. Characteristics of Ideal
Fungicide
1. High field performance
(i). Inherent fungi toxicity
(ii). Active constituents
(iii). Good coverage
(iv). Initial deposition
(v). Residual effect

15. Characteristics of Ideal
Fungicide
(2). Low Phytotoxicity
(3). Stability in Storage
(4). Stability after Dilution to Spray Strength
(5). Low Toxicity to Human beings & Cattles
(6). Cheap & Easily Available
(7). Compatibility
(8). Simple to Prepare & Easy to Apply

16. Formulations of
Fungicides
(1). Wettable Powders or WP
(2). Dust or Dustable Powder or DP- 4-10% AI
(3). Emulsifiable Concentration or EC
(4). Granules or G
(5). Suspension Concentrate or SC
(6). Slurries or Water Dispersible Powder for Slurry
Treatment or WS
(7). Solution

17. Sulphur Compounds S compounds
Inorganic Organic
• i. Elemental Sulphur
i. Ziram a). Dust sulphur
ii. Febam b). Wettable sulphur
iii. Thiram ii. Lime sulphur
iv. Menab vi. Nebam

18. Sulphur Dust
S - dust should be very fine
1. Particle size- 200-300 mesh or 47-74 µ
2. Natural ‘S’ from ores is grounded & used
3. Rate – 25 kg/ha – Rotary duster
4. S- control Powdery mildew
5. S- dust can be used as ST for sorghum smut

19. Wettable Sulphur
• Formulated as 80% WP
• T.N.- Thiovit, Cosan, Microsulf, Ultra sulphur
• Rate - 0.2- 0.25%
• Control- P. M. of Veg. & Fruits crops

20. Lime Sulphur
1. Calcium polysulphide = Ca S2
2. L. S used as spray – Use only in Fe/Zn pots Rock lime
= 20 lbs Sulphur = 15 lbs Water = 50 gallon • Method –
add water into lime & add S slowly & stir of suspension
continue – colour become golden yellow
3. Use supernatant
4. Dose- 0.75- 1.0 gallon/ 100 gallon water for cucurbits,
vegs. Pea etc.
5. 1.0 – 2.o gallon/ 100 gallon for woody trees * 1 gallon =
3.78541 Litre

21. Organic S fungicides
Derivatives of Dithiocarbamates (Dithiocarbamic acid)
Dithiocarbamic acid is methylated to unstable the fungicidal
property
Zn, Fe, are used to stabilize dimethyl dthiocarbamate
1. Ziram
Zincdimethyl dithiocarbamate
T. N. – Corozate, Hexazir, Zirberk, Zerlate
Used as spray- @ 0.15-0.25%
Diseases controlled- E. B. of potato, Alternaria sp.,
Colletotrichum sp. Rust etc.

22. 2. Ferbam
Ferric dimethyldithiocarbamate
• T. N. – Fermate, Hexferb, Ferberk, Coromet
• Dose - @ 0.1 - 0.3% as foliar spray
• Dis. controlled-Fungal diseases of veg & fruits
• 4. Zineb • Zinc ethylene bisdithiocarbamate • T. N. –
Indofil Z- 78, Lonacol, Parzate C, Dupont • Used as foliar
spray • Dose - @ 0.2 - 0.3% • Dis. controlled- Rust, D.M.,
Alternaria blight, L.B. of potato, Anthracanose,
cercospora leaf spot

23. 3. Thiram
Tetramethyal thirum disulphate
T. N. – Arasan, Hexathir, TMTD, Thylate,
Thiride
Used as S.T
Dose - @ 0.2 - 0.3% & as soil fungicide- 10-25
kg/ ha
Dis. Controlled- Damping off, stem gall of
coriander

24. 4. Zineb
Zinc ethylene bisdithiocarbamate
 T. N. – Indofil Z- 78, Lonacol, Parzate C, Dupont
 Used as foliar spray
 Dose - @ 0.2 - 0.3%
 Dis. controlled- Rust, D.M., Alternaria blight, L.B. of potato,
Anthracanose, cercospora leaf spot

25. 5. Maneb
Mengnese ethylenbisdithiocarbamate
 Not available in India
 In India- Dithane M-45 (Maneb 78% + Zinc 2%)
 More effective than Zineb
 Dose - @ 0.2 - 0.3% as foliar spray
 Dis. controlled- Anthracanose of tomato, tobacco, cucurbits,
D.M. of pea, rust of pea & wheat

26. 6. Nabam
Disodium ethylenebisdithiocarbamate
1. Not available in India
2. T. N. – Vapam, Chemvape
3. Used as fumigant fungicide
4. Dose - @ 1.5 – 2.5 litre for 10 SQM area
5. Used for – weed flora, fungi & nematode

27. 7. Copper Fungicides
1.Copper sulphate preparations
2. Copper carbonate preparations
3. Copper oxychloride preparations
4. Cuprous oxide preparations
5. Oxine copper preparations
1. Bordeaux Mixture
1. 1882 – Prof. Millardet
2. Bordeaux University France
3. D.M of grape–Medoc- till Oct. remain green
4. Published – 1885 but used 1887

28. Bordeaux Mixture
4 : 4 : 50 = 0.8% Copper sulphate : Lime : Water 5 : 5 : 50 = 1.0% Copper
sulphate : Lime : Water 6 : 6 : 50 = 1.2% Copper sulphate : Lime : Water
Mostly used – 4 : 4 : 50 (0.8%)
Objective – Prepare 1% Bordeaux Mixture Requirements – CuSO4, Lime,
Water, Earthen pots, Muslin cloth, Rod, Potassium feracynide Method – i).
Dissolve 5 kg CuSO4 in 250 Litre water in earthen/ wooden pot ii).
Dissolve 5 kg lime in 250 Litre water & filter in muslin cloth iii). Mixed both
mixture in other pot very well by shaking with rod
Testing for Phytotoxicity: • Take few amount of mixture in test tube • Add
few drops of potasium feracynide in tubes • If reddish brown deposit
appear than add lime Precautions : • Use immediately after preparation –
60 gm sugar in 500 lt. BM • Never use metallic container for B. M.
preparation (Fe/Zn) • Test the phytotoxicity level before use – leaf burning,
russeting Disease control: D.M., P.M., L.B., Anthracanose, Leaf spots,
citrus canker etc.,

29. 2,Bordeaux Paste
Bordeaux Paste CuSO4 : Lime : Water 450 gm : 450 gm : 4.5
Litre Uses - ↓ amount of water used as dressing Exp. Stem
Secretion of Coconut
3. Burgundy Mixture or Soda Bordeaux Mixture • Mason – 1887
• Burgundy in France • Sodium Carbonate (Na2CO3) used in
place of lime
i). 5 kg : 6.25 kg : 500 litre CuSO4 : NaCO3 : Water ii). 10 kg :
12.5 kg : 500 litre CuSO4 : NaCO3 : Water iii). 4 kg : 5 kg : 500
litre CuSO4 : NaCO3 : Water • Test acidity/alkalinity by litmus
paper before use • If blue litmus – become red – acidic – make
neutral • B. M. not used now a days because lime is available &
it is less effective & costly than B.M.

30. 3. Burgundy Mixture or Soda
Bordeaux Mixture
Mason – 1887
Burgundy in France
Sodium Carbonate (Na2CO3) used in place of lime
i). 5 kg : 6.25 kg : 500 litre CuSO4 : NaCO3 : Water ii). 10
kg : 12.5 kg : 500 litre CuSO4 : NaCO3 : Water iii). 4 kg : 5
kg : 500 litre CuSO4 : NaCO3 : Water
Test acidity/alkalinity by litmus paper before use
If blue litmus – become red – acidic – make neutral
B. M. not used now a days because lime is available & it is
less effective & costly than B.M.

31. 4. Cheshunt Compound
Bewley – 1921
Copper sulphate ( CuSO4. 5 H2O) = 2 parts
Ammonium carbonate (NH4)2CO3) = 11 parts
Mix above compounds
Keep the mixture in a bottle for 24 hrs before use
otherwise Ammonia will be loss
Add 30 gm mixture in 9 litre water
Used for- drenching for damping off for disinfection •
Not store in metallic containers

32. 5.Chaubattia Paste
Developed in Govt. Fruit Research Station Chaubattia i.
Copper carbonate = 800 gm
ii. Red Lead powder = 800 gm
iii. Raw Linseed oil = 1 litre • Prepare a paste in a earthen/
glass pots by mixing above
Used as wound dressing
Exp. – black stem of apple & pear, die back of peach, collor
rot of apple & peach

33. 6. Copper oxychloride
compounds
low soluble copper is available in the form of copper
oxychloride
Copper oxychloride CuCl2.3Cu(OH)2- reacting with air
4-12% - copper oxychloride – dust
50% copperoxychloride – spraying (WP)
T. N. – Blitox- 50, Fyttolan, Blue copper 50, Cupramar •
Used – Pernospoirales fungi
Spraying - @ 3-4 kg/1000 litre water & Dusting - @ 25-35
kg/ha

34. 7. Cuprous oxide
4-12% - – dust
50% – spraying (WP)
T. N. – Fungimar, Perenox, Cuprocide, Cuprous- 50 • Used – Blight, D.M., & Rust fungi
Spraying -@ 3-4 kg/1000 litre water & Dusting - @ 25-35 kg/ha
Dicarboximide Fungicides
1. Iprodione :
3-(3, 5-dichlorophenyl)-N-(1-Methyl,2,4-dioxo-1- imidazolidinecarboximide)
T. N. – Rovral, Glycophene, Chipco 26019
Contact fungicide • 50 WP or Dust
Used- Botrytis, Sclerotinia, Monilinia, Alternaria,
Vinclozolin:
3-(3, 5-dichlorophenyl)-5-ethenyl-5- methyl-2, 4-oxazolidinedione
T. N. – Ronilan, Ornalin, Vorlan
50 % WP
Contact fungicide
Used- Botritis, Sclerotinia & Monilinia etc.

35. Mercury Fungicides
Mercury fungicides Inorganic Organic
1. Mercuric chloride HgCl2
2. 1. Ethyl mercury chloride (EMC)
3. 2. Mercurus chloride Hg2Cl2
4. 2. Phenyl mercury acetate (PMA)
5. 3. Methoxyethyl mercury chloride (MMC)
Inorganic- HgCl2 was used earlier as ST but due to high toxicity now not used.
Organic- use is restricted only for ST
Are sold in India under the following names
Agrosan GN- pink colour- used as ST- Jowar, Maize, Bajara, Cotton etc. – 1% metallic mercury 1. Agallal-
radish colour- 3-6%- wet treatment – S. cane setts & potato 1. Ceresan - i. ceresan wet ii. Ceresan dry 1%
metalic used as ST.- Maize, Jowar, Bajara etc.
Aretan – T. N. Aretan-6, 6% metallic used for ST. of S. cane & potato

36. HETROCYCLIC NITROGEN
COMPOUNDS
1. Captan-
N- trichloromethyl-thio-4-cyclohexene-1, 2-dicarboximide
T. N. – Captan, Esso fungicide 406, Orthocide 406,
Vanicide 89 • Used as ST & SLT
Available as WP 83% in India
ST - @ 0.2 - 0.3%
SLT- @ 20 – 25 kg/ha
Dis. Cont. – Damping off of seedlings caused by Pythium

37. 2. Captafol
Cis - N- 1,1,2,2, tetrachloromethylthio - 4- cyclohexane 1-2,
dicarboximide
T. N. - Difolatan- 80 WP
Dis. Cont. – Alternaria blight & L. B. of potato
3. Folpet-
N- trichloromethylthiophthalimide
T. N. – Folpet, Pholtan, Orthophaltan
Used as Captan – this also act against P. M.

38. QUINONE FUNGICIDES
1. Chloronil –
2,3,5,6-tetrachloro-1, 4-benzequinone
T. N. – Spergan
Used as ST
Not available in India
Dis. Cont. – Smut & bunts
@4-8 auns/100 lbs

39. QUINONE FUNGICIDES
2. Dichlone
2,3 – dichloro 1,4 –napthoquinone
T. N. – Phygon, Phygon XL
Used as ST but as FS in apple scab
@ 1- 4 auns/100 lbs • Dis. Cont. - Smuts
• 48. BENZENE COMPOUNDS 1. Diazoben – • Sodium-p-
dimethylaminobenzene diazosulfonate • T. N. – Dexon • Used as ST
& SLT • Dis. Cont. – Damping off & root rot
• 49. 2. Chlorothalonil – • 2,4,5, 6-tetrachloro-isophthalonitrile • T. N. –
Kavach, Bravo, Termil- 75% WP & 20% dust • Used as F. S &
dusting • Dis. Cont. – E. B., D. M. Rust, scab etc. • @ 0.1- 0.2%
• 50. 3. Dinocap • Methyl heptyl dinitrophenyl • T. N. – Karathane,
Arathane, Mildex • Used as FS • Dis. Cont. – PM

40. BENZENE COMPOUNDS
1. Diazoben –
Sodium-p-dimethylaminobenzene diazosulfonate
T. N. – Dexon
Used as ST & SLT
Dis. Cont. – Damping off & root rot
2. Chlorothalonil –
2,4,5, 6-tetrachloro-isophthalonitrile
T. N. – Kavach, Bravo, Termil- 75% WP & 20% dust
Used as F. S & dusting
Dis. Cont. – E. B., D. M. Rust, scab etc.
@ 0.1- 0.2%
3. Dinocap
Methyl heptyl dinitrophenyl
T. N. – Karathane, Arathane, Mildex
Used as FS
Dis. Cont. – PM

41. BENZENE
COMPOUNDS
2. Carbendazim
Methyl-2-benzimidazole carbamate or MBC
T.N.- Bavistin, Derosal, Bengard, Dhanustein
More stable than Benomyl
50% or 60% WP & 25% Seed dressing powder
Used as ST & FS
Used for- PM, scab, dipping of fruits & roots
3. Thiabendazole
2, 4 – thiazolyl - benzimidazole or TBZ
T.N.- TBZ, Mertect, Thiabendazole W-7
60% WP
Used as ST, FS, soil drench, soil mix & fruit dip
Used for – rotting of fruits as post harvest dip or spray in apple, pear, banana & citrus
4. Thiophanates
1, 2 - bis (3 - ethoxycarbonyl 2- thioureido) benzene
T.N.- Topsin, Topsin M, Roko, Alert, Cercobin
60% or 70% WP
Used as FS
Used for- Cercospora leaf spot, PM, Sheath blight, Scab

42. Oxathins Compounds
1. Carboxin
5,6, dihydro-2-methyl-1,4-oxathin, 3 -carboximide
T.N.- Vitavax, Vitavax 200
75% WP, 10% dust
Used as ST for smut, bunt, R. solani, S. rolfsi
SLT- 1.5 kg/acre
2. Oxycarboxin
5, 6, dihydro – 2 – methyl - 1, 4 - oxathin, 4 - dioxide
T.N.- Plantvax, Plantvax L
Not as good as Vitavax, specialy for basidiomycotina
75% WP, 10% dust, 5% granules
ST - 0.1-0.5% - L.S. of wheat, barley, flag smut of wheat, smut of
sorghum, R. solani, S. rolfsi & rust pathogen
FS - 0.1 - 0.2% - rust pathogen – 2 - 3 sprays

43. Acylalanines or Acylanilides
1. Metalaxyl
N-(2-Dimethylphenyl)-N-(methoxyacetyl)-alanine
methylester
T.N.- Ridomil, Apron, Ridomil MZ-72
Specific to oomycetes – pernosporales
Used as ST, SLT & FS
25% & 50 % WP, granules – 1%, 2% & 5% and 5% EC
FS- L. B. of potato, DM of pea & cotton
Ridomil MZ- DM of mustard

44. Acylalanines or
Acylanilides
2. Furalaxyl
Methyl- N - 2, 6 dimethylphenyl-n-furoyl (2)
alaninate
T.N.- fongarid, fonganil
25% & 50% WP, 10% dust
Specific to Phytium & Phytophthora spp. – for soil
borne diseases

45. Pyrimidines
1. Dimethirimol
5-n-butyl-2-dimethylamino-4-hydroxy-6-methylpyrimidine
T.N.- Milcurb
1.25%, 10% & 12.5% liquid form & 5% granules
Used for PM of cucurbits & chrysanthimum
Cucurbits @ 1-4 kg/ha
2. Ethirimol
5-n-butyl-2-dimethylamino-4-hydroxy-6-methylpyrimidine
T.N.- Milstem
80% WP & 20% aqueous solution
Used for PM of cereals (wheat & barley) @ 0.25%
64. Morpholines 1. Tridemorph • N-tridecyl-2,5-demethylmorpholine • T.N.-
Calixin • 75% EC • Used for PM of various crops • Effective against PM of
various crops but higher dose is phototoxic • PM of barley, Cucurbits ,
beetlvine & rust of g.nut

46. Morpholines
• 1. Tridemorph
N-tridecyl-2,5-demethylmorpholine
T.N.- Calixin
75% EC
Used for PM of various crops
Effective against PM of various crops but higher dose is
phototoxic
PM of barley, Cucurbits , beetlvine & rust of g.nut

47. Organophosphates
1. Kitazine
O,o-diisopropyl-s-benzylthiophosphate
T.N.- Kitazin P
Insecticidal properties – leaf & plant hopper
48% EC , 17% granules & 2% dust
Used for brown spot of maize, leaf blight of onion,
verticillum wilt of egg plant & blast of rice

48. Alkyl Phosphates
1. Fosetyl- AL
Aluminium tris-o-ethyl-phosphonate
T.N.- Aliette, EPAL
80% WP & 10% granules
Translocated both upward & downward
Toxic to honey bees, fish & birds
Effective to oomycetes- Pythium, Phytophthora, DM

49. Piperazine
1. Propiconazole
1-(2- (2, 4-dichlorophenyl) - 4propyl-1,3 - dioxolan - 2- ylmethyl)
1H-1, 2, 4 - trizole
T.N.- Tilt 3.6 E & Tilt 250 E
Effective against- karnal bunt, rust, sheath blight of rice, PM of
grape.
2. Tricyclazole
5 – methyl - 1, 2, 4 - trizole (3, 4 - b) benzothiazole
Beam, Blaside
20% & 75% WP, 1% dust & 4% granules
Used as soil drench & FS
Effective against- blast of rice

50. Antibiotics
Alexander Flaming – 1929 Penicillin from Penicillum
notatum “A chemical compound produced by one
microorganism that is able to kill or inhibit the growth of
other microorganisms”
Properties of Antibiotics 1. Effective in small amount 2.
Specific 3. Mostly antibacterial but also antifungal 4.
Systemic in action 5. May be Tem. Sensitive or not be
Mode of Action 1. Direct action on plant surface 2. Direct
action inside plant tissues 3. Action after transformation
within the plant 4. Action direct on host

51. Antibiotic Production
(A). Antibiotics derived from amino acids
1. Penicillin - Pencillium notatum
2. Chloromietin – Streptomyces venezuelae
3. Bacitracin – Bacillus licheniformis & B. subtilis
4. Viomycin – S. puniceus & S. floridae
B. Antibiotic derived from sugars
1. Streptomycin- S. griseus
2. Neomycin- S. fradiae
3. Gentamicin- S. spp.
4. Paranomycin – S. rimosus
C. Antibiotics derived from Acetate
1. Tetracycline – S. spp.
2. Puromycin – S. alboniger
3. Griseofulvin – P. griseofulvum
4. Fumagillin – Aspergillus fumigatus