Chemical control of plant disease

CHEMICAL CONTROL OF PLANT DISEASES

DR. RAJBIR SINGH Assistant Professor

Department of Plant Pathology Gochar Mahavidyalaya, Rampur Maniharan, Saharanpur (UP), India Affiliated to Ch. Charan Singh University, Meerut (UP), India

Email: rajbir25805@yahoo.com, rajbirsingh2810@gmail.com

Cell No. 91-9456613374

CHEMICAL CONTROL

1. Protectant chemical

2. Eradicant chemical

3. Chemotherapeutants

Methods of Application

1. Spraying

2. Dusting

3. Fumigation

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

Demerits of Spraying1. 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

Seed Treatment1. Seed disinfectants - a. internally seed borne b. Exp. Vitavax, Carbedazim

2. Seed disinfestants

a. externally seed borne

b. Exp. Copper corbonate

3. Seed protectants

a. soil borne pathogen

b. Exp. Thiram, Captan

Methods of Seed Treatment

1. Dry seed dressing/ treatment

2. Slurry treatment

3. Seed dip method

4. Planter hopper box seed treatment

Methods of Soil Treatment1. 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

8. Soil fumigation

FungicideLatin 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”

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

(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

(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

Characteristics of Ideal Fungicide1. High field performance

(i). Inherent fungitoxicity

(ii). Active constituents

(iii). Good coverage

(iv). Initial deposition

(v). Residual effect

(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

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

Sulphur Compounds

S compounds Inorganic Organic

i. Elemental Sulphur i. Ziram a). Dust sulphur ii. Febam b). Wettable sulphur iii. Thiramii. Lime sulphur iv. Menab vi. Nebam

Sulphur Dust• S - dust should be very fine

• Particle size- 200-300 mesh or 47-74 µ

• Natural ‘S’ from ores is grounded & used

• Rate – 25 kg/ha – Rotary duster

• S- control Powdery mildew

• S- dust can be used as ST for sorghum smut

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

Lime Sulphur• Calcium polysulphide = Ca S2• 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

• Use supernatant• Dose- 0.75- 1.0 gallon/ 100 gallon water for

cucurbits, vegs. Pea etc.• 1.0 – 2.o gallon/ 100 gallon for woody trees

* 1 gallon = 3.78541 Litre

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.

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

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

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

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

6. Nabam

• Disodium ethylenebisdithiocarbamate

• Not available in India

• T. N. – Vapam, Chemvape

• Used as fumigant fungicide

• Dose - @ 1.5 – 2.5 litre for 10 SQM area

• Used for – weed flora, fungi & nematode

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

• 1882 – Prof. Millardet

• Bordeaux University France

• D.M of grape–Medoc- till Oct. remain green

• Published – 1885 but used 1887

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.,

2. 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.

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

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

6. Copper oxychloride compounds

• In India 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

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,

Fusarium, Rhizoctonia etc.

2. 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.

Mercury Fungicides

Mercury fungicides Inorganic Organic

1. Mercuric chloride HgCl2 1. Ethyl mercury chloride (EMC)

2. Mercurus chloride Hg2Cl2 2. Phenyl mercury acetate (PMA) 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

1. 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.

4. Aretan – T. N. Aretan-6, 6% metallic used for ST. of S.

cane & potato

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

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.

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

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

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

Systemic Fungicide

1966 - Von Schemeling and Kulka

Systemic fungicides on application to various plant parts absorbed by plant tissues, Tranlocated upward or downward, control plant diseases away from place of application are detectable in plants in its form or as metabolites.

Advantage

• Control when pathogen already established

• Cover foliage & inflorescence more effectively

• Away from place of application

• More specific inhibitors of biosynthetic process

• Translocated hence used at low con.

• Effectivity of non systemic governed by correct placement

of chemical but not in SF

• Not subject to prolong weathering after spray as in non SF

Movement of Fungicides in Plants1. Apoplastic trsnslocation

upward movement

by Xylem

2. Symplastic translocation

downward movment

by phloem

3. Ambimobile

up & down both side movement

4. Toxophere

many S.F. are metabolized or degraded inside plants

Benzimidazole Compounds

1. Benomyl

• Methyl -N-(1-butylcarbamoyl)-2 benzimidazole carbamate

• T.N.- Benlate, Tersan 1991, Krimenomyl

• 50% WP

• Used as ST, FS

• Used for- Smut, PM, Scab, Blast etc.

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

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

Acylalanines or Acylanilides1. 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

• Apron 35 SD- seed dressing – collar rot & damping off

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

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%

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

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

Alkyl Phosphates1. 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

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

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

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

Thank You