Post Harvest Diseases.pptx

This slide tries to address status of Postharvest diseases of different vegetables, fruits, cereals and legumes, their symptoms, losses and
integrated management .
The disease which develops on harvested parts of the plants like seeds, fruits and also in vegetables are called post-harvest disease. It leads to measurable qualitative and quantitative food loss along the supply chain, starting at the time of harvest till its consumption or other end uses. In Nepal, different studies have shown the postharvest losses of fruits and vegetables are 20-50% (Gautam and Bhattarai, 2012) and 6-12% losses in worldwide.

1. The presentation on post harvest disease of fruits, vegetables, cereals, legumes and their management Sarad Pokhrel MSc.Ag Plant Pathology Agriculture and Forestry University

2. Postharvest Disease The disease which develops on harvested parts of the plants like seeds, fruits and also in vegetables are called post-harvest disease. It leads to measurable qualitative and quantitative food loss along the supply chain, starting at the time of harvest till its consumption or other end uses. .In  Nepal, different studies have shown the postharvest losses of fruits and vegetables are 20-50% ( Gautam and Bhattarai , 2012 ) and 6-12% losses in worldwide.

3. How grains, ripen fruits and vegetables become subject to attacks of various microorganisms upon harvesting?? Disease resistance weakens as a result of separation from the parent plant. Harvested fruits and vegetables are rich in moisture and nutrients, which suit the development of pathogens. Upon ripening the fruits and vegetables often become more susceptible to injury. series of physiological processes occurs during prolonged storage which leads to the senescence of tissues and, in parallel increased susceptibility to weak pathogens.

4. Factors affecting disease development Pre-harvest factors, harvesting and handling Cultivar Planting materials Environmental conditions Cultural practice Harvesting

5. Factors affecting disease development B. Inoculum level C. Storage conditions Temperature Relative humidity and moisture Storage atmosphere

6. Some major post-harvest disease of Cereals A. Ear and kernel molds of corn 1. Aspergillus   species ( A. flavus , A. parasiticus , etc.; Capable of producing an aflatoxin which is toxic to livestock and human.

7. Some major post-harvest disease of Cereals Ear and kernel molds of corn 2. Fusarium spp.: white to pink mold; Fumonisin  toxin, which is toxic to livestock (particularly horses), can be produced

8. Some major post-harvest disease of Cereals Ear and kernel molds of corn 3. Gibberella   zeae ( bright pink and red to white ), Potential mycotoxins include vomitoxin  or deoxynivalenol  (DON) and zearalenone (ZE), which are deadly to livestock.

9. Some major post-harvest disease of Cereals Ear and kernel molds of corn 4. Penicillium   spp : Powdery blue-green mold  .

10. Some major post-harvest disease of Cereals Ear and kernel molds of corn 5. Cladosporium   herbarum 6. Stenocarpella   maydis ( Diplodia ): White to gray mold 7. Nigrospora   sphaerica , synonym N.  oryzae ( ear or cob rot) .

11. Some major post-harvest disease of Cereals B. kernel molds of wheat 1. Penicillium verrucosum primarily produced Ochratoxin , 2. Fusarium graminearum produced DON and ZE   3. Aspergillus spp

12. Some major post-harvest disease of Cereals C. Aspergillus , Penicillium , and Fusarium genera are responsible for production of most important mycotoxins often occur in rice, which includes: Aflatoxins Citrinin DON Sterigmatocystin Patulin , etc.

13. Some major post-harvest disease of Fruits and Vegetables Fruit rot, dark spot, sooty mold Primary host : Stone and pome fruits, grapes, papaya, tomato, pepper, eggplant cucumber, melon, watermelon, squash, cabbage, cauliflower, broccoli, corn, pea, bean. carrot, potato, sweet potato, onion Pathogen : Alternaria alternata (Fr.) Keissler

14. Some major post-harvest disease of Fruits and Vegetables 2. Gray mold disease Primary host : strawberry , raspberry, cherry, grape, pome and stone fruits, persimmon, citrus fruits, tomato, pepper, eggplant, cucumber, squash, melon, pumpkin, artichoke, cabbage, cauliflower, lettuce, broccoli, pea, bean, carrot, onion, potato, sweet potato Pathogen : Botrytis cinerea Pers. ex Fr. Perfect state: Botryotinia fuckeliana (de Bary ) Whetzel

15. Some major post-harvest disease of Fruits and Vegetables 3. Anthracnose Primary host : Avocado, mango, papaya, guava, citrus fruits, Pome and stone fruits(Bitter rot), Banana( crown rot) Pathogen : Colletotrichum gloeosporioides ( Penz .) Sacc . Perfect state: Glomerella cingulata ( Stonem .) Spauld & V. Schrenk , Colletotrichum gloeosporioides , Colletotrichum musae

16. Some major post-harvest disease of Fruits and Vegetables 3. Dry or soft rot Primary host : tomato, pepper, eggplant, melon, squash, pumpkin, watermelon, cabbage, celery, artichoke, asparagus, corn, carrot, potato, sweet potato, onion, garlic Pathogen : Fusarium spp.

17. Some major post-harvest disease of Fruits and Vegetables 4. Green mold/Blue mold Primary host : citrus fruits ( green mold exclusively), Tomato, cucumber, melon , pome fruits mainly, but also stone fruits(Blue mold) Pathogen : Penicillium digitatum Sacc , Penicillium expansum (Link) Thom

18. Some major post-harvest disease of Fruits and Vegetables 5.Watery soft rot: Primary host : Stone and pome fruits. grape, avocado, papaya, strawberry, raspberry, cherry, tomato, pepper, eggplant, carrot, melon, pumpkin, squash, pea, bean, sweet potato Pathogen : Rhizopus stolonifer ( Ehr . ex Fr.) Lind

19. Some major post-harvest disease of Fruits and Vegetables 6. Bacterial Soft rot Primary host : tomato , pepper, melon, squash, pumpkin, cucumber, cabbage, cauliflower, lettuce, celery, broccoli, spinach, asparagus, pea, bean, potato, sweet potato, onion Pathogen : Erwinia carotovora spp . carotovora (Jones) Dye Erwinia spp ., Pseudomonas syringae ( Kleb .) Kleb . Pseudomonas spp

20. Some major post-harvest disease of Fruits and Vegetables 7. Watery white rot, cottony rot Primary host : Citrus fruits, cabbage, cauliflower, lettuce. celery, broccoli, artichoke, pea, bean, carrot, eggplant, melon, cucumber, pumpkin, squash, onion, garlic Pathogen : Sclerotinia sclerotiorum (Lib.) de Bary

21. Some major post-harvest disease of Fruits and Vegetables 8. Brown rot citrus caused by Phytophthora citrophthora (Smith & Smith) Leon . 9. stem-end and fruit rot, green-yellow mold of citrus caused by Trichoderma viride Pers. ex S.F. Gray 10. Brown rot of stone fruits mainly, but also pome fruits caused by Monilinia fructicola ( Wint .) Honey 11. stem-end rot, dry black rot of papaya caused by Phoma caricae-papayae ( Tarr ) Punith . And so on.

22. 1.Management of post harvest disease of fruits and vegetables Maintaining the host resistance Treatments and conditions that lead to delayed ripening and senescence Indirectly suppress postharvest disease development. Includes include low-temperature storage, low-O 2 and high-C0 2 atmospheres, ethylene removal from the atmosphere, growth regulators, calcium application

23. 1.Management of post harvest disease of fruits and vegetables Maintaining the host resistance Cold storage: Storage at low temperature is the main method for reducing deterioration of harvested fruits and vegetables inhibition of ripening and senescence of the host and extension of the period during which it maintains its resistance to disease. inhibition of pathogen development by subjecting it to a temperature unfavorable for its growth.

24. 1.Management of post harvest disease of fruits and vegetables Maintaining the host resistance 2. Modified and controlled atmosphere 'CA storage' generally implies precise control of O 2 and CO 2 concentrations in the atmosphere, MA storage' is broader and may indicate any synthetic atmosphere, arising intentionally or unintentionally, in which the composition of its constituent gases cannot be closely controlled.

25. 1.Management of post harvest disease of fruits and vegetables Maintaining the host resistance 2. Modified and controlled atmosphere controlled atmosphere i.e. low O 2 levels or high CO 2 levels suppress various stages of the pathogen growth, and its enzymatic activity. Maintains the resistance of the host to infection by keeping it in a superior physiological condition In order to obtain appreciable reduction of spore germination, mycelial growth and sporulation in many fungal species, O 2 concentrations of less than 1% are required

26. 1.Management of post harvest disease of fruits and vegetables Maintaining the host resistance 3. Growth regulators Suppress decay development indirectly, by retarding ripening and senescence processes in fruits and vegetables It may be of special importance mainly for fruits and vegetables that cannot be stored at low temperatures because of their cold sensitivity Applying the synthetic auxin 2,4-dichlorophenoxy acetic acid (2,4-D) to citrus fruits prior to storage , resulting in considerable reduction of stem-end rot.

27. 1.Management of post harvest disease of fruits and vegetables Maintaining the host resistance 4. Calcium Application Calcium contributes to preserve the structural integrity and functionality of membranes and the cell wall during fruit ripening and senescence Calcium treatment may reduce storage disorders, such as bitter pit and internal breakdown in apples It was thus found that pre-harvest calcium sprays reduced the rate of storage losses caused by Gloeosporium spp. in apples, or Botrytis and Geotrichum rots in stored grapes ( Miceli et al., 1999)

28. 1.Management of post harvest disease of fruits and vegetables B. Physical Methods Heat Treatments It may be applied by means of hot water dips and sprays, hot vapor or dry air, or infrared or microwave radiation It can be Short-term heating 40°C (generally 44-55°C) for a short time L ong-term heat treatments usually (38-46°C ), for a longer duration (12 h to 14 h) For example, postharvest decay of strawberries caused by Botrytis cinerea and Rhizopus stolonifer was controlled by exposure of the fruit to humid air at 44°C for 40-60 min.

29. 1.Management of post harvest disease of fruits and vegetables B. Physical Methods Ionizing radiation : may directly harm the genetic material of the living cell, leading to mutagenesis and eventually to cell death Due to deep penetration ability, it irradiates microorganisms in wounds, and also quiescent or active infections. Presence of oxygen and water content of the cell are major factors for its effectiveness. Low doses of UV-C light (wavelength of 190-280 nm) to induce disease resistance in a wide range of fruits and vegetables

30. 1.Management of post harvest disease of fruits and vegetables C . Biological methods refers to the use of naturally found microorganisms which antagonize the postharvest pathogens we wish to suppress Strains of Pseudomonas putida and Chryseobacterium indologenes were found to reduce the incidence of gray mold rot on fruits under field conditions Candida oleophila (Aspire) to control P. expansum , Botrytis cinerea , and R, stolonifer under various cold-storage conditions Pseudomonas syringae is a biological products for commercial postharvest applications to citrus fruits: Field sprays of strawberry flowers with antagonistic non-pathogenic Trichoderma viridae isolates resulted in a decreased incidence of gray rot ( B. cinerea ) during storage

31. 1.Management of post harvest disease of fruits and vegetables Chemical methods Pre-harvest chemical treatments application of broad-spectrum protective fungicides to the developing fruit on the plant, in order to prevent spore germination or infection establishment in the lenticels or in floral remnants of the fruit. Oranges are sprayed with benomyl before harvest, to prevent the development of stem-end rot, which arises from infections of Diplodia natalensis and Phomopsis citri .

32. 1.Management of post harvest disease of fruits and vegetables Chemical methods 2. Sanitation may be achieved through the immediate disposal of every rotted fruit or vegetable, or by immersing it in a disinfectant solution Use of chlorinated water at 38-43°C to wash tomatoes in the packinghouse prevents the buildup of inoculum in the water Formaldehyde, isopropyl alcohol, quadronic ammonium compounds, captan or other chemicals must be used for disinfecting packinghouse or store rooms.

33. 1.Management of post harvest disease of fruits and vegetables Chemical methods 3. Post harvest Chemical treatments selection of the appropriate chemical compound depends on the sensitivity of the pathogen to the chemical substance the ability of the substance to penetrate through surface barriers into the infection site the tolerance of the host, as expressed both by injury and other phytotoxic effects, and by any adverse effect upon the quality of the product

34. 1.Management of post harvest disease of fruits and vegetables Chemical methods 3. Post harvest Chemical treatments Captan (N-trichloromethylmercapto-4-cyclohexene-l,2-dicarboximide ), which is a bicarboximide fungicide, has been proven effective as a postharvest dip against decay development in various fruits and vegetables, such as strawberries, peaches, cherries, pears, figs and potatoes Dicloran (2,6-dichloro-4-nitroaniline, DCNA, botran ) is effective against several postharvest fungi Sulfur dioxide (SO2) is applied as a postharvest fumigation to grapes in order to eradicate spores of Botrytis cinerea

35. 1.Management of post harvest disease of fruits and vegetables Chemical methods 3. Post harvest Chemical treatments The benzimidazole compounds - thiabendazole (TBZ), benomyl.are active against a broad spectrum of pathogenic fungi . Like Penicillium digitatum , Monilinia fructicola , Colletotrichum gloeosporioides and so on Metalaxyl ( ridomil ), which is an acylalanine fungicide, acts as a strong inhibitor of the various developmental stages of Phytophthora spp. Essential oils and plant extracts are sources of antifungal activity against a wide range of fungi for eg . palmarosa ( Cymbopogon martini ) and red thyme ( Thymus zygis ) showed the greatest inhibitory effect on B. cinerea spore germination at the lowest concentration.

36. 1.Management of post harvest disease of fruits and vegetables Chemical methods 3. Post harvest Chemical treatments Gel derived from Aloe vera plants has been found to have antifungal activity against four common postharvest pathogens: Penicillium digitatum , P. expansum , B. cinerea and A. alternata . The natural gel suppressed both germination and mycelial growth, with P. digitatum and A. alternata being the most sensitive species

37. 2. Management of postharvest disease of cereals and pulses Avoid Infestation of through the use of fumigants. This helps to reduce rapid growth of storage fungi . The stored grain should not be unripe or too old; it should be clean , and be free of mechanical damage The moisture content should kept at levels below the minimum required for the growth of the common storage fungi i.e. below 12% The temperature of stored grain should kept as low as possible, . As it slows down the respiration of grain and prevents an increase of moisture in grain.

38. 2. Management of postharvest disease of cereals and pulses Ideally, grain should be cooled after drying and maintained at 1°C to 4 °C for the duration of storage, while during the summer months the grain temperature can be maintained between 10 and 15°C . Both reductions in oxygen tension and increase in carbon dioxide concentrations can have profound effects on the growth of fungi Decreasing O 2 to<0.14% and increasing CO 2 >50% is required for inhibition of mycelial growth and will prevent mycotoxin production.

39. Any Queries???

40. Thank you!!