Fungicides: Benefits and Risks.

1. Name: Mohd Bilal Khan.
Cass: B.sc (Hons).
Year: Final.
This Photo by Unknown author is licensed under CC BY-SA.
Department of Botany (A.M.U).

2. Fungicides:
Benefits
and Risks

3. Contents.
Introduction.
Origin.
History.
Mechanism of Fungicides.
Benefits of Fungicides.
Risks of Fungicides.
Conclusions.

4. Introduction.
Q : What are fungicides ?
Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or
their spores.
A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses
of yield, quality, and profit.
Fungicides are used both in agriculture and to fight fungal infections in animals.
Chemicals used to control oomycetes, which are not fungi, are also referred to as fungicides, as oomycetes
use the same mechanisms as fungi to infect plants.
Fungicides can either be contact, translaminar or systemic.
Contact fungicides are not taken up into the plant tissue and protect only the plant where the spray is
deposited.
Translaminar fungicides redistribute the fungicide from the upper, sprayed leaf surface to the lower,
unsprayed surface.
Systemic fungicides are taken up and redistributed through the xylem vessels
Few fungicides move to all parts of a plant. Some are locally systemic, and some move upwardly.
Examples: Bordeaux mixture,
Captan , EBDCs , etc.

5. Introduction.
What are parasitic fungi ?Q :
The parasitic fungal species transmit diseases and form
relations with other organisms, in which the fungus
benefits from the association and damages the host
organism (human beings and plants).
Such fungi as Endothia parasitica, Ceratocystis
ulmi, Puccinia graminis are parasites of plants, while
fungi of the genus Aspergillus or Candida
albicans carry infections to the human organisms.

6. Origin and History.
Farmers have been at the mercy of plant diseases since plants were first domesticated.
The mysterious appearance of blights and mildews, apparently coming from nowhere, led
to theories of gods, vapors, demons, and decay as causes of disease.
Beginning in the early 1800s, plant scientists and chemists began the long journey to discover
and invent fungicides that would reduce disease losses.
1807 – The First Fungicide.
1885 – The First Foliar Fungicide.
1915 – Broad-Spectrum Control of Seed-Borne Disease.
1940 – The First Broad-Spectrum Protectant Fungicides.
1969 – The First Systemic Seed Treatment .
1976-1996 – Fungicides with Indirect Modes-of-Action.

7. F.R.A.C.
Established in 1927.
Fstands for FUNGICIDE.
Rstands for RESISTANCE.
A stands for ACTION.
C stands for COMMITTEE.
F.R.A.C is a specialist technical group of crop life International.

8. Mechanism
of
fungicide.
Example: TPTH and
sulphur.

9. Mechanism of
fungicides.
Systemic fungicides.
Example: Phenylamides FRAC A-1.

11. Mode of action.
The manner in which the fungicide affects the fungus is called the mode of action.
Fungicides are divided into chemical groups based on their mode of action.
Most of the fungicides used in pulse and cereal crops falls into five main chemical groups
based on their modes of action.
Benzimidazoles (Group 1).
Dicarboximides (Group 2).
DMI - Triazoles (Group 3).
SDHI (Succinate Dehydrogenase Inhibitors) (Group 7).
QoI (Quinone Outside Inhibitor) (Group 11).

12. Benefits of fungicides.
Protect young plants against Anthracnose leaf blight and eyespot, among other diseases.
Benefits of Fungicides on early seasoning.
Improve stalk strength with reduced risk of lodging and green snap for better
harvestability.
Promote greener plants with a better window of grain fill.
Improve yield results when combined with a tassel spray rather than
from a tassel spray alone.
Applying a fungicide such as Delaro or Stratego at this phase is not only convenient, it also
offers early season disease control and more complete plant coverage.

13. Benefits of fungicides.
Benefits of using fungicides in a dry season.
A plant becomes stressed when there is a lack of moisture which kick-starts their defense
mechanisms. Defense mechanisms of plants includes:
Premature ethylene production.
Ethylene is a chemical naturally produced by plants at many stages of life, typically
when maturity and ripening occurs.
Applying a fungicide will help a plant overcome drought and heat stress through
reducing the amount of ethylene produced and increasing its water use
efficiency.
When a plant is more effective at using the available water, it stays cooler and keeps the plant
from shutting down and aborting pods.

14. Benefits of Fungicides in a rainy season.
Benefits of fungicides.
It is true that most diseases require higher moisture levels, humidity and rainfall to help
spread disease through the crop canopy.
There are some diseases such as Powdery Mildew, that will actually break
down when there is high rainfall.
Fusarium Head Blight spores can be distributed with the wind
as well as rainfall and only requires high humidity to become
activated.
Crop canopies can trap disease, and fungicide can help plants reach their full
potential.

15. Risks of fungicides.
One side effect of fungicides is phytotoxicity, or a toxic effect on beneficial plants.
It's important to use the right type of fungicide on the right plant at
the right time, or you may have problems.
For instance, the fungicide Azoxystrobin, frequently used on grapes, can kill some
apple varieties, while Trifloxystrobin is harmful to certain grape cultivars but not
others.
Some fungicides are growth specific, such as triazole + QoI fungicides that can't
be applied to soybeans later than a growth stage known as R5.

16. Risks of fungicides.
Environmental toxicology.
The presence and persistence of fungicides in agricultural soils can cause adverse effects to
soil organisms, such as earthworms and micro-organisms, and the crucial functions these
organisms are responsible for (e.g. the breakdown of organic matter, facilitating nutrient
cycling).
Negative impacts caused by fungicide residues can have lasting impacts on the fertility and
health of agricultural soils.
Fungicide residues, which make their way into surface and ground waters, have the
potential to cause adverse effects to the structure (i.e. biodiversity) and functioning of
aquatic ecosystems.

17. Fungicides contains a variety of heavy metals such as :-
Risks of fungicides.
Copper.
Manganese.
Cobalt etc.
Excessive use of fungicides leads to Biomagnification.

18. Conclusions.
Fungicides are widely used in horticultural production systems to
ensure crop quality and production.
However, the use of such fungicides may cause adverse effects to
terrestrial and aquatic ecosystems if fungicide residues persist in soil,
or if they migrate off-site to surface and ground waters.
For efficient and safe use of fungicide,the problem has to be diagnosed correctly.
Before applying a fungicide make sure about the cause of the disease ( Is it a disease ? If so what
is causing it ? Fungi ? Which one ?) and when ( spring,fall etc.)
How often to apply the fungicide. The timing of the fungicide application can enhance the
effectiveness of the product and prevent additional sprays.

19. Conclusion.
• Smart use of fungicides not only
protect our plants,but it will also protect
our health and the environment.

20. Thank you.