Elimination of insect, disease ,vermin, and similar unwanted plagues of pests by chemical inputs. • Fungi and Bacteria – main cause. • Parasite (on living matter) / saprophytes (dead produce). • fungi - pH (2.5 – 6) ; bacteria - neutral • Chlorine & sulfur dioxide • Chlorine –sanitizer ; 50 to 200 ppm in water to reduce the number of microorganisms present on the surface of the fruit

1. CHEMICAL TREATMENT-
DISINFESTATION
PRESENTED BY:-
VIKAS TIWARI
16031

2. INTRODUCTION:-
• Elimination of insect, disease ,vermin, and similar unwanted plagues of pests by
chemical inputs.
• Fungi and Bacteria – main cause.
• Parasite (on living matter) / saprophytes (dead produce).
• fungi - pH (2.5 – 6) ; bacteria - neutral
• Chlorine & sulfur dioxide
• Chlorine –sanitizer ; 50 to 200 ppm in water to reduce the number of
microorganisms present on the surface of the fruit

3. Chlorination in a hydrocooler
(re-circulating)
Chlorination on a brush bed
(non-re-circulating)

4. • Mode of infection of micro organism
Fungal and bacterial - Mechanical injuries and cut surfaces of the crop, growth
cracks,pest damage, stomata, lenticels & cuticles
Viruses- Vectors
• Damage by micro organism
Physical loss - edible matter (partial or total )
Eg: Fungi Aspergillus flavus and A. parasitica produce aflatoxin like mycotoxin on
ground nut kernels & coconut
Mycotoxin -carcinogenic - maximum permitted levels - 50 ppb in fruit juices.

5. Disinfestation methods
• Field management
Sanitation, proper nutrition, wind breaks, resistant cultivars, care in handling ,irrigation
and harvesting time
• Pre-harvest spraying
Field sprays with fungicides
• Post harvest chemical treatments
Thiobendazole and Benomyl
Extracts of Eucalyptus globula & Punica granatum.
1-3% formaldehyde solution,hypochlorite or SOPP (Sodium ortho phenylphenate).

6. Methods of Chemical Application
• Dipping
Diluted chemicals + hot water at 55℃ -10 min. ‘Cascade’ application
Eg. Citrus, apples, pineapple & root vegetables.
• Spraying
Eg. Citrus, apple etc.
• Electrostatic Sprays / Thin film of Coating
Pesticides droplet + electric charge
Principle- Particle all have the same electrical charges hence, thus repel each other.
Eg.: Potato and crown rot of banana

7. Dipping Spraying Electrostatic Sprays

8. • Dusting
Wood ash + lime-Yam. Fungicides + talc - Potato.
• Fumigation / Vapour treatment
Product + gastight room + Gas.
0.5- 1% SO2 for 20 min followed by Ventillation.
Storage, periodic (every 7-10 days) fumigations at 0.25%.
Eg. 5-18 ppm SO2 -grapes for decay control
• Absorbent paper
fungicides soaked & dried pads- cut surfaces
Pads- absorbs latex from the cut surfaces & prevent patogen invasion
Potassium aluminum sulphate.
dichlorovos based pest strip -flowers export.

10. • Cold storage
Storing the produce at <1.6℃ for 16 days
• High temperature
40-55℃ - 15 minutes.
Eg- Mango anthracnose -dipping at 55 ℃ -5 min.
• Biological control –
yeast Candida guilliermondii -Penicillium spp. incorporated into citrus waxes
Bacillus subtilis - Mango anthracnose and stem end rot

11. The biocontrol Bio-Save is registered for
postharvest use.

12. Chemicals used to control spoilage and quality in fruit and
vegetables:-
ITEM CHEMICAL
Apple Sodium - phenyl phenate
Banana Thiobendazole, Benomyl
Citrus Sodium carbonate, Borax, SOPP, Biphenyl,
2,4- D, N Cl3 fumigation
Mango Hot water, Benomyl
Grapes SO2 Fumigation
Papaya Hot water
Pomegrenate Ethyl oleate
Potato Hypochlorite
Carrot & Cabbage Thiobendazole , Benomyl
Onion Benomyl
Sweet Potato & Tomato 2 , 6-dichloro-4-nitroaniline

13. List of post harvest diseases of fruits:-
Fruit Disease Causal Organism
Banana Crown rot Acremonium sp, Curvularia sp, Colletotrichum
musae, Fusarium semitectum, Verticillium sp
Ber Fruit rot Alternaria sp, Phomopsis sp, Colletotrichum sp.
Citrus Black rot Alternaria citri
Grey mold Botrytis cinerea
Green mold Penicillium digitatum
Stem-end rot Diaporthe citri, D. medusae, D. natalensis.
Guava Anthracnose Colletotrichum gloeosporioides
Kiwifruit Stem rot Botrytis cinerea
Litchi Skin injuries Aspergillus sp., Penicillium sp., Rhizopus sp.
Mango Anthracnose Colletotrichum gloeosporioides
Stem-end rot Botryodiplodia theobromae

14. Post harvest pests