This document discusses fungicides, their classification, properties, and toxicity. It focuses on sulfur, pthalmides, and dithiocarbamates. Sulfur is a broad-spectrum fungicide and insecticide that can cause poisoning through ingestion or absorption. Its mechanism of action is not fully clear but may involve antagonizing essential metals. Pthalmides like captan have low mammalian toxicity and are degraded enzymatically. Dithiocarbamates have low acute toxicity in mammals and environmental persistence, and their mechanism may involve inhibiting sulfur-containing enzymes.

1. Ajay Raj Ojha
B. V. Sc. And A. H,6th sem
AFU,Rampur

2. FUNGICIDES
 Chemical used to prevent /eradicate
fungus infections
 Plants and seeds treated with fungicides
 Have low to moderate mammalian
toxicity
 Mainly toxic effects include
developmental defects and cancer etc.

3. CLASSIFICATION
 Mainly on the basis of chemical structure
and source
1.Inorganic Fungicides : sulphurs, metallic
salts etc.
2.Organic
Fungicides:Chlorphenols,Dithiocarbamae
s,Pthalmides,Benzimidazoles,
Organolin compounds, Organomercury
compounds , Azoles ,
Morpholines,Halogenated substituted
monocyclic amines etc.

4. SULPHUR(lime sulphur)
 Broad-spectrum fungicide and
insecticide
 Calcium polysulphide and barium
polysulphide preparations were used in
ancient times
 Poisoining may observed in all species

5. Properties
 Tasteless, odourless, multivalent
nonmetal, yellow crystalline solid
 Have suffocating odour burns with blue
flame(SO2)
 Insoluble in water but soluble in
carbondisulphide

6. Sources Of Toxicity
 Ingestion of storage sacs or sulphur
treated feeds
 Inadverent use of higher dose during
treatment of worms and infection as well
as tonic
 From the sources where sulphur is
used as raw materials
 Through volcanic emissions

7. Toxicity
 Sublimed/titrated sulphur is less toxic
but Micronized sulphur is more toxic
 Lethal Dose is 100-1000mg/kg in sheep
and in horses 1000-1500mg/kg

8. Toxicokinetics
 Good oral absorption- absorbed as
sulphides /amino acids-oxidized into
sulphate-kidney –excreted
 Topical absorption directly goes to
systemic circulation

9. Mechanism Of Action
 Exact MOA is not clear
Ingestion
Local effect on gut membrane
laxative effects
irritant action on GI mucosa
abdominal pain and colic

10. MOA cont…
 Antagonistof essential metals like Cu,
Ca, K
 Nerve degeneration,inflammatory
vascular/joint degeneration
 Crohn’s Disease

11. Clinical Signs
 GI effects- abdominal
pain,diarrhoea(haemorrhagic
often),anorexia,tympany,constipation etc.
 Neurological Effects-
dullness,laasitude,abnormal
behavior,mydriasis,convulsion,tremor etc.
 Respiratory effects-dyspnoea,pulmnary
edema,wheezing
 Miscellaneous signs-
Ataxia,jaundice ,skin
infections,sweating,death in acute cases
within several hours

12. Postmortem Findings
 Not significant but
congestion,haemorrhagic suffusions and
petechiae along GI tract,congestion on
lungs,urinary bladder may be noticed
DIAGNOSIS
By clinical signs,history,necropsy etc.
Treatment
Only symptomatic and supportive (GI
sedative Fluid therapy)

13. PTHALMIDES
 Broad spectrum fungicids
 Few acute toxicity only reported
 Low in mammalian toxicity
 Eg:Captan,captafol

14. Properties
 Less soluble in water and less volatility
 Pthalmide ring provides certain physical
properties but toxic effect is by side
chains(chlorine ,carbon etc.)
Toxicity
LD50 in rats is 900-12500mg/kg but 250-
500mg/kg produce acute toxicity in
ruminants cause toxicity depends upon
protein diet

15. Toxicokinetics
 Limited toxicity
 Degraded by non enzymatic as well
enzymatic chemical reaction in gut
 Absorption and elimination within 24-48
hours from the body

16. Mechanism Of Action
 Exact mechanism is not clear
Captan and Folpet
DNA
Point Mutations
Defective protein synthesis

17. Clinical signs
 Not specific but hydrothorax, gastro
enteritis,petechiae on gall bladder etc.
Treatment
no specific antidote but supportive and
symptomatic care

18. DITHIOCARBAMATES
 Broad chemical class
 Sulphur derivative of carbamates but poor
inhibitor of cholinesterase enzyme
 Two groups depending upon use of
monoamine during production
1.Monoalkyal dithiocarbamates-derived from
primary amines eg;metham
2.Dialkyl dithiocarbamates- derived from
secondary amines eg;thiram
 Low order of acute toxicity

19. Toxicity
 Low to moderate acute mammalian toxicity
 Low environmental persistence and low
cumulative potential
 Lethal dose is 2-5gm/kg in rats and
230mg/kg in cat
 500ppm in diet of quials and patridges
inhibit egg laying
 Thiram and Ziram used as bird and
mammal repellant

20. Toxicokinetics
 Limited absorption
 Metabolized by liver

21. Mechanism Of Action
 Have multiple actions but exact
mechanism is not clear
1.Inhibition of –SH containing enzymes(α-
ketoglutaroxidase,pyruvic dehydrogenase
,succinic dehydrogenase)
2. metal chelation(Cu of enzyme dopamine
β-hydroxylse
decrease in synthesis of noradrenalline
nerve transmission blockage

22. MOA contd….
3. Interfernce with the release of
gonadotrophin realeasing hormone
Thyroid gland dysfunction ,disrupt
hormonal control of ovulation
4.Inhibit the alcohol dehydrogenase
enzyeme potentiation of toxicity of
co-administered ethanol

23. Clinical Signs
1.Digestive Disorders-
nausea,vomiting,dyspnoea,ataxia,clonic
convulsions, carcinogenic in high dose
2.Ethylenethiourea- maneb and zineb like
compound break down to form ETU, which
is carcinogenic,mutagenic, teratogenic and
antithyroid etc.
Others toxicity are- loss of body weight,irritant
to mucus membrane,eyes,retardation in
growth and reproductive problems etc.

24. Post Mortem Findins
 Non specific
 Focal necrosis of GI tract,hapatic and
renal pathology,incraese in thyroid gland
etc
Treatment
Nonspecific treatment like supportive and
symptomatic therapy is recommended.