Fungicides, Classification, FRAC MoA.pptx

Detailed classification of fungicides, Mode of action, Strobilurins, Banned fungicides

1. T h e r a p y - Groups o f F u n gicides Th er apy : A tr ea tment o r an a tt em pt t o cu re t he disease . ✓The word ‘fungicide’ originated from two latin words, viz, ‘fungus’ and 'caedo '. 'f un gu s' m ea ns "a mushroom" ' an d caedo ' means ' to kill' . Thus the fungicide is any agency /chemical which has the ability to kill the fungus. ✓ According to this meaning, physical agents like ultra violet light and heat should also be considered as fungicides. ✓ However, in common usage, the meaning is restricted to chemicals only .

2. Characters of an ideal fungicide 1. It should n ot c a u s e phytotoxicity . 2. It should have lon g shelf life . 3. Stability during dilution . 4. It should be less t o x i c to human being, cattle, earth worms , microorganisms etc. 5. It should be a target specific in its action . 6. It m u s t s h o w compatibility with other agrochemicals . 7 . It must be a cheaper one . 8 . It should be available in different formulations . 9 . E as y to transport .

3. Classification of Fungicides . Fungicides can be broadly grouped based on their (i) mode of action (ii) general use and (iii) chemical composition. I. Based on Mode of Action . Protectant(Prophylactic) :Fungicide which is effective only if applied prior to fungal infection is called a protectant, eg., Zineb, Sulphur . Therapeutant :Fungicide which is capable of eradicating a fungus after it has caused an infection,eg :Carboxin, Aureofungin . Usually chemotherapeutant are systemic in their action. Eradicant :those which remove pathogenic fungi from an infection court. eg. Organo-Mercurials , lime sulphur .

4. II. Based on G eneral U ses . 1. Seed P rotectants : Eg. Captan, T hiram, Carbendazim . 2. Soil Fungicides (preplant) : Eg.Chloropicrin, Formaldehyde , Vapam . 3. Soil Fungicides (for growing plants) : Eg. Bordeaux mixture, C opper oxy chloride, PCNB . 4. Foliage and B lossom : Eg. Ferbam , Zineb , Mancozeb , Chlorothalonil . 5. Fruit Protectants : Eg. Captan, Maneb , Mancozeb .

5. 6. Eradicants : Eg. Organomercurials, L ime Sulphur . 7. Tree wound dressers : Eg. Bordeaux paste, C haubattia paste. G e n erally t h e s e a r e applied to the trees and s h r ubs a f t e r t r a i n ing and Pruning operation . 8. Antibiotics : Eg. Actidione, Griseofulvin, Streptomycin, Streptocycline .

6. III. Based on Chemical Composition . Major group of fungicides used include salts of toxic metals and organic acids, organic compounds of sulphur , quin o nes and heterocyclic nitrogenous compounds. Copper, Mercury , Z inc, T i n and N i ckel are some of the metals used as base for inorganic and organic fungicides. ✓ F u n g i cides m a d e u p of N on metal s l i k e sulphur, chlorine , phosphorous a r e a l so t h ere . ✓ C o m m o n Groups of Fungicides – Copper Fungicides, Sulphur Fungicides and Mercury Fungicides , B e n z e n e a n d S y s t e m i c F u n g i c ides .

7. S u l p hur F ungicides. Co n t a c t a n d P r o tective i n a c t i o n . 1. I n o r g a n i c S u l p h ur : • E l e m e n t a l S u l p h ur • L i m e S u l p h u r ✓ B o t h a r e u s e f u l t o c o n t rol Powdery Mildew a n d A p p l e s c a b d i s e ase . 2 . O r ganic Sulphur : D i t h i o c a r b a m a t e s i ) M o n o a l k y l : Z i n e b , M a n e b , M a n c o z e b , N a b a m ( A l g a e a n d l e a f s p o t ) , Vapam ( Effective on S o i l B o r n e P a t h o gens a n d a l s o a c t s a s a H e rbicide , N ematicide ) . i i ) D i a l k y l : Z i r a m ( A n t h r a c n o s e ) , F e r b a m , T h i r a m ( c a n b e u s e d in s e e d t r e a t m e n t both as dry p owder or as a s l urry ) .

8. Co pp er Fungicides : F ir st M en tioned by P re vo st t o co nt ro l wh ea t bu nt disease . ✓Bor de aux Mixture: contains 8 lbs of CuSO4 + 8 lbs of lime + 10 0 gallons of water. Developed by P MA M il le rd et t o co ntrol D ow ny m il de w of g ra pe s. CuSO4 + Ca (OH)2 -- -> Cu(OH)2 + CaSO4. Cupric h ydroxide is the active principle and is toxic t o fungal spores. ✓ Burgundy mixture: In this mixture lime is replaced by sodium carbonate or washing soda . developed by M as on . It s a go od s ub st it ute fo r bo rd ea ux m ix tu re an d us ed i n co pp er se ns itive crops . it contains 1 kg of copper sulphate and 1 kg of sodium carbonate in 100 litres of water.

9. ✓ C h aubattia Paste : Developed by V. B Singh. Prepared b y mixing 800g of copper carbonate and 800g of red lead in litre of raw linseed oi l . Act's a s a w o u n d dresser . ✓ C O C : Copper O x y c h l o r i d e e f f e ctive against Oomycetes f u n g i a n d h a s A n t i b a c t erial p roperty . T h i s c a n b e a p p lied a s f o l i a r fungicide as w ell a s s o i l f ungicide . ✓ C u p r o u s h y d r o x i de : Protective f u n g i c i d e m a i n l y u s e d in Seed t r e atment .

10. •Phytotoxicity of Bordeaux is reduced by increasing the ratio of hydrated lime to copper sulfate. •For spraying young, actively growing plants, the amounts of both copper sulfate and hydrated lime are reduced. •In “fixed” or “insoluble” copper compounds, the copper ion is less soluble than that in the Bordeaux mixture. Therefore, less phytotoxic than Bordeaux but are effective as fungicides. ex: CuSO4,Copper oxides . •Inorganic Sulphur may cause injury in hot (temperatures above 30°C), dryweather, especially to sulfur-sensitive plants such as tomato, melons, and grapes .

11. M er cury F un gicides : ✓ H ig hl y fu ng it ox ic ,due to their residual toxicity in soil and plants and their extreme toxicity nature to animal and human beings, the use of mercury fungicides is being discouraged. • In most of the countries, the use of mercury fungicides is banned and in countries like India , the use of mercury fungicides is restricted only in seed treatment for certain crops. I. Inorganic Mercur ia l Fungicides: • Mercuric chloride (t re at in g tu be rs a nd p ro pa ga ti ve m at er ia ls of o th er ro ot c ro ps ) • Mercurous chloride ( l im ited to Soil ap pl ication on ly ). Because it c auses p hy to toxicity .

12. II. Organomercurials . ✓ Methoxy ethyl mercury c hloride ✓ Ethyl Mercury Chloride ✓ Phenyl mercury chloride . mainly u s e d for treatment of seeds and planting materials . Heterocyclic Nitrogen Compound s . ✓ Captan (Kittleson ' s Killer) : u s e d s e e d d r e s s ing f u n g i c i d e . ✓ Captafol : Protective fungicide . Benzene compounds . ✓ Quintozene (PCN B) : u s e d f o r s e e d treatment and soil a p p l ication . ✓ Dinocap : C o n t a ct , A c a r i c i d e a n d P o w d ery M i l d e w f u n g i c i d e .

13. Organo–Phosphorous . ✓ E d i f e n p h o s : e f f e c tive a g a inst Rice B l a s t a n d Brown s p o t . ✓ I p r o b e n f o s : S h e a t h b l i g h t o f r i c e . Organo Tin compounds . ✓ Fentin hydroxide a n d F e n t i n a c e t a t e : t o control f o l i a r diseases . Systemic Fungicides . Any compound capable of being freely translocated after penetrating the plant is called systemic . H owever, have not been very successful in the cases of trees and shrubs . 1 ) O x a t h i i n : The first systemic fungicide Carboxin was developed by Von Schmeling and Kulka in 1966. C a r b o x i n e f f ective a g a i nst s m u t d i s e a s e s . Trade name is Vitavax .

14. (ii) Oxycarboxin : Trade name Plantvax , used against rusts . B e n z i m i d a z o l e s . ✓ B e n o m y l ✓Bavistin - superior fungicide s which acts a s a good eradica n t and protectant . It is used as spray, seedling dip, seed treatment, soil drench and as post harvest treatment of fruits. Thiophanates : i t h a s t h i o u r e a g r o u p . ✓ T h i o p h a n a t e ✓ T h i o p h a n a t e M e t h y l : B r o a d S p e ctrum Fungicides . Morpholines ✓ Tridemorph : fungicide with S ystemic a n d Eradicant action , highly effective against P o w d e r y m i l d e w s .

15. Phenylamides : ✓Metalaxyl : Ef fe ctive ag ai ns t Oo my cetes fu ng i. Triazoles : Most active on powdery mildews, rusts and leaf spot fungi. e x: Tr ic yc la zo le (specific fungicide used against paddy blast fungus ) an d Propiconazole. Pyrimidines. ✓ Triadimefon ✓Triadimenol : T he se a re u se fu l to control P ow dery M il de ws a nd r us ts . Hydroxy Pyrim idines . ✓Ethirimol ✓ Dimethirimol: e ff ective a ga inst Powdery Mi ldews . Phenol derivative . ✓Chloroneb : Ac ti ve a ga in st s to ra ge d is ea se s of f ru its .

16. ✓ F o s e t y l Aluminium i s a systemic fungicide effective against Oom y c e tes fungi which s h o w s A c r o p e t a l m o v e m ent w h e n a p p l ied t o p l a n t s u r f a ce belongs to O r g a n o p h o s p h o r u s c o m p o u n d .

17. Strobilurin g r o u p of Fungicides ✓This group contains the newest and most important fungicides. The first such fungicide was isolated from the wood-rotting mushroom fungi Strobilurus tenacellu s.✓There are now 10 major strobilurin fungicides on the market, which account for 23-25 % of the global fungicide sales eg: Azoxystrobin, kresoxim-methyl, picoxystrobin. ✓Strobilurins are mostly contact fungicides,but some strobilurins,such as azoxystrobins, move trans-laminarly and systemically through the vascular system of the plant. Sometimes it shows growth-promoting effects also. ✓They have a unique mode of action like they inhibit electron transfer in mitochondria, disrupting metabolism and prevents growth of the target fungi.

18. In-vitro effect of newer fungicides on mycelial growth in biocontrol fungus Trichoderma harzianum . Dinesh1,*, Bisht KS2, Tewari AK2 ( 2 1 6 ) A b s t ract : T r i c h o derma harzia n um (Th 14) was tested in - vitro for its compatibility with different concentrations of commonly used newer fungicides. Six systemic viz., M e t a l a x y l , hexaconazole, t e bunaconazole, difenaconazole, propinconazole, carbendazim and two contact fungicides mancozeb and captan were used, each at concentrations of 25, 50 and 100 ppm .

19. A progressive increase in percent inhibition of radial growth in the fungus was observed as the concentrations of the fungicides increased. Among the systemic fungicides 100% growth inhibition was recorded at all the concentrations tested except metalaxyl. Toxicity of the contact fungicides was lower than the systemic fungicides, among t h i s Mancozeb was compatible, no inhibition was observed at lower concentration (25 ppm). The inhibition ranged from 8.75 to 23.75% for metalaxyl, B u t for o t h e r systemic f u n g i c i d e s it's m o r e t h an 8 % .

20. Fungicides group According to FRAC. • Group Name The Group Names listed are based on chemical relatedness of structures which are accepted in l i t erature (e.g. The Pesticide Manual). They are based on different sources (chemical structure, site o f action ). Chemical or Biological Group Grouping is based on chemical considerations. Nomenclature is according to IUPAC and Chemical a bstract name. Taxonomic information may be used for agents of biological origin.

21. C hemical name Trade name . Copper oxychloride. Blitox-50. Copper sulphate. Blue copper. Ethyl mercury chloride. Ceresan Methoxy ethyl mercuric chloride Aretan Benlate. Benomyl Carbendazim. Bavistin Maneb. Dithane M-22 Mancozeb. DithaneM-45,Indofil Zineb. Dithane Z-78. Propineb. Antracol Tebuconazole. Folicur

22. Thiocarbamate fungicides - Reliable tools in resistance management and future outlook-Tarlochan S Thind(2012) A bs tr act : Among contact fungicides, dithiocarbamates have remained successful and are used worldwide. Example mancozeb, zineb, ziram, and propineb which have a multi-site mode of action and broad-spectrum disease control . So it makes them the most common mixture partners with a number of single-site fungicides as part of resistance management strategies. Like ethylene-bis-dithiocarbamates such as mancozeb in delaying the evolution of phenylamide resistance in several oomycete phytopathogens that laid the groundwork for mixture strategies . Dithiocarbamates are only the surface protectants, and have to be applied prior to pathogen infection. Dithiocarbamates will likely to play a key role as reliable resistance management tools to prolong the efficacy of single-site fungicides.

23. ✓These multi-site fungicides are important components of resistance management strategies because they delay development of resistance to single-site fungicides in mixtures. ✓ Use as mixture partners and in rotations :Since dithiocarbamate fungicides are effective against both resistant and sensitive strains of the pathogen, such mixtures reduces the rate of evolution of resistance. ✓ Synergy with partner fungicides :A 1:6 ratio of azoxystrobin and propineb exhibited stronger synergistic action over the chilli fruit rot causing fungi Phytophthora capsici. ✓ Slow release of active ingredients :Using polyethylene glycol as a “capping agent”, a nanoformulation of mancozeb has been developed that shows a good control of target pathogens.

24. Resistance Management S trategie s . ✓ A v o i d repetitive u s e o f s a m e f u n g i c i d e . . ✓ L i mit t h e number of treatments . ✓ A pply protective sprays early in the epidemic . ✓ A p p l y recommended do s a ge o n l y . ✓ I ntegrate with non-chemical methods . i , e f o l l o w I D M p r a c t i ces .

25. R e f e r ences : • Thiocarbamate fungicides - Reliable tools in resistance management and future outlook Tarlochan S Thind and Derek W Ho Hollom. • h t t p : / / p p q s . g o v . i n • h t t p : / / e c o u r s e o n l i n e . i a s r i . i n • FRAC Code List ©*20 20 :Fungal control agents sorted by cross resistance pattern and mode of action . • An Overview of Strobilurin Fungicide Degradation:Current Status and Future Perspective Yanmei Feng, Yaohua Huang, Hui Zhan, Pankaj Bhatt and Shaohua Chen.